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fs/eventpoll.c
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// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* fs/eventpoll.c (Efficient event retrieval implementation) * Copyright (C) 2001,...,2009 Davide Libenzi |
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* |
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* Davide Libenzi <davidel@xmailserver.org> |
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*/ |
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#include <linux/init.h> #include <linux/kernel.h> |
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#include <linux/sched/signal.h> |
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#include <linux/fs.h> #include <linux/file.h> #include <linux/signal.h> #include <linux/errno.h> #include <linux/mm.h> #include <linux/slab.h> #include <linux/poll.h> |
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#include <linux/string.h> #include <linux/list.h> #include <linux/hash.h> #include <linux/spinlock.h> #include <linux/syscalls.h> |
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#include <linux/rbtree.h> #include <linux/wait.h> #include <linux/eventpoll.h> #include <linux/mount.h> #include <linux/bitops.h> |
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#include <linux/mutex.h> |
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#include <linux/anon_inodes.h> |
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#include <linux/device.h> |
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#include <linux/uaccess.h> |
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#include <asm/io.h> #include <asm/mman.h> |
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#include <linux/atomic.h> |
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#include <linux/proc_fs.h> #include <linux/seq_file.h> |
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#include <linux/compat.h> |
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#include <linux/rculist.h> |
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#include <net/busy_poll.h> |
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/* * LOCKING: * There are three level of locking required by epoll : * |
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* 1) epmutex (mutex) |
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* 2) ep->mtx (mutex) |
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* 3) ep->lock (rwlock) |
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* * The acquire order is the one listed above, from 1 to 3. |
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* We need a rwlock (ep->lock) because we manipulate objects |
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* from inside the poll callback, that might be triggered from * a wake_up() that in turn might be called from IRQ context. * So we can't sleep inside the poll callback and hence we need * a spinlock. During the event transfer loop (from kernel to * user space) we could end up sleeping due a copy_to_user(), so * we need a lock that will allow us to sleep. This lock is a |
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* mutex (ep->mtx). It is acquired during the event transfer loop, * during epoll_ctl(EPOLL_CTL_DEL) and during eventpoll_release_file(). * Then we also need a global mutex to serialize eventpoll_release_file() * and ep_free(). * This mutex is acquired by ep_free() during the epoll file |
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* cleanup path and it is also acquired by eventpoll_release_file() * if a file has been pushed inside an epoll set and it is then |
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* close()d without a previous call to epoll_ctl(EPOLL_CTL_DEL). |
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* It is also acquired when inserting an epoll fd onto another epoll * fd. We do this so that we walk the epoll tree and ensure that this * insertion does not create a cycle of epoll file descriptors, which * could lead to deadlock. We need a global mutex to prevent two * simultaneous inserts (A into B and B into A) from racing and * constructing a cycle without either insert observing that it is * going to. |
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* It is necessary to acquire multiple "ep->mtx"es at once in the * case when one epoll fd is added to another. In this case, we * always acquire the locks in the order of nesting (i.e. after * epoll_ctl(e1, EPOLL_CTL_ADD, e2), e1->mtx will always be acquired * before e2->mtx). Since we disallow cycles of epoll file * descriptors, this ensures that the mutexes are well-ordered. In * order to communicate this nesting to lockdep, when walking a tree * of epoll file descriptors, we use the current recursion depth as * the lockdep subkey. |
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* It is possible to drop the "ep->mtx" and to use the global |
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* mutex "epmutex" (together with "ep->lock") to have it working, |
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* but having "ep->mtx" will make the interface more scalable. |
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* Events that require holding "epmutex" are very rare, while for |
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* normal operations the epoll private "ep->mtx" will guarantee * a better scalability. |
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*/ |
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/* Epoll private bits inside the event mask */ |
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#define EP_PRIVATE_BITS (EPOLLWAKEUP | EPOLLONESHOT | EPOLLET | EPOLLEXCLUSIVE) |
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|
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#define EPOLLINOUT_BITS (EPOLLIN | EPOLLOUT) |
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#define EPOLLEXCLUSIVE_OK_BITS (EPOLLINOUT_BITS | EPOLLERR | EPOLLHUP | \ |
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EPOLLWAKEUP | EPOLLET | EPOLLEXCLUSIVE) |
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/* Maximum number of nesting allowed inside epoll sets */ #define EP_MAX_NESTS 4 |
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#define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event)) |
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#define EP_UNACTIVE_PTR ((void *) -1L) |
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#define EP_ITEM_COST (sizeof(struct epitem) + sizeof(struct eppoll_entry)) |
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struct epoll_filefd { struct file *file; int fd; |
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} __packed; |
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|
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/* Wait structure used by the poll hooks */ struct eppoll_entry { /* List header used to link this structure to the "struct epitem" */ struct eppoll_entry *next; |
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/* The "base" pointer is set to the container "struct epitem" */ struct epitem *base; /* * Wait queue item that will be linked to the target file wait * queue head. */ wait_queue_entry_t wait; /* The wait queue head that linked the "wait" wait queue item */ wait_queue_head_t *whead; |
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}; /* |
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* Each file descriptor added to the eventpoll interface will * have an entry of this type linked to the "rbr" RB tree. |
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* Avoid increasing the size of this struct, there can be many thousands * of these on a server and we do not want this to take another cache line. |
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*/ struct epitem { |
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union { /* RB tree node links this structure to the eventpoll RB tree */ struct rb_node rbn; /* Used to free the struct epitem */ struct rcu_head rcu; }; |
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/* List header used to link this structure to the eventpoll ready list */ struct list_head rdllink; |
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/* * Works together "struct eventpoll"->ovflist in keeping the * single linked chain of items. */ struct epitem *next; |
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/* The file descriptor information this item refers to */ struct epoll_filefd ffd; |
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/* List containing poll wait queues */ |
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struct eppoll_entry *pwqlist; |
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/* The "container" of this item */ struct eventpoll *ep; |
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/* List header used to link this item to the "struct file" items list */ |
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struct hlist_node fllink; |
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/* wakeup_source used when EPOLLWAKEUP is set */ |
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struct wakeup_source __rcu *ws; |
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/* The structure that describe the interested events and the source fd */ struct epoll_event event; |
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}; /* |
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* This structure is stored inside the "private_data" member of the file |
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* structure and represents the main data structure for the eventpoll |
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* interface. */ struct eventpoll { |
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/* |
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* This mutex is used to ensure that files are not removed * while epoll is using them. This is held during the event * collection loop, the file cleanup path, the epoll file exit * code and the ctl operations. |
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*/ |
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struct mutex mtx; |
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/* Wait queue used by sys_epoll_wait() */ wait_queue_head_t wq; /* Wait queue used by file->poll() */ wait_queue_head_t poll_wait; /* List of ready file descriptors */ struct list_head rdllist; |
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/* Lock which protects rdllist and ovflist */ rwlock_t lock; |
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/* RB tree root used to store monitored fd structs */ |
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struct rb_root_cached rbr; |
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/* * This is a single linked list that chains all the "struct epitem" that |
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* happened while transferring ready events to userspace w/out |
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* holding ->lock. |
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*/ struct epitem *ovflist; |
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/* wakeup_source used when ep_scan_ready_list is running */ struct wakeup_source *ws; |
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/* The user that created the eventpoll descriptor */ struct user_struct *user; |
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struct file *file; /* used to optimize loop detection check */ |
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u64 gen; |
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struct hlist_head refs; |
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#ifdef CONFIG_NET_RX_BUSY_POLL /* used to track busy poll napi_id */ unsigned int napi_id; #endif |
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#ifdef CONFIG_DEBUG_LOCK_ALLOC /* tracks wakeup nests for lockdep validation */ u8 nests; #endif |
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}; |
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/* Wrapper struct used by poll queueing */ struct ep_pqueue { poll_table pt; struct epitem *epi; }; |
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/* |
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* Configuration options available inside /proc/sys/fs/epoll/ */ |
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/* Maximum number of epoll watched descriptors, per user */ |
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static long max_user_watches __read_mostly; |
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/* |
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* This mutex is used to serialize ep_free() and eventpoll_release_file(). |
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*/ |
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static DEFINE_MUTEX(epmutex); |
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|
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static u64 loop_check_gen = 0; |
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/* Used to check for epoll file descriptor inclusion loops */ |
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static struct eventpoll *inserting_into; |
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/* Slab cache used to allocate "struct epitem" */ |
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static struct kmem_cache *epi_cache __read_mostly; |
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/* Slab cache used to allocate "struct eppoll_entry" */ |
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static struct kmem_cache *pwq_cache __read_mostly; |
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|
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/* * List of files with newly added links, where we may need to limit the number * of emanating paths. Protected by the epmutex. */ |
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struct epitems_head { struct hlist_head epitems; struct epitems_head *next; }; static struct epitems_head *tfile_check_list = EP_UNACTIVE_PTR; static struct kmem_cache *ephead_cache __read_mostly; static inline void free_ephead(struct epitems_head *head) { if (head) kmem_cache_free(ephead_cache, head); } static void list_file(struct file *file) { struct epitems_head *head; head = container_of(file->f_ep, struct epitems_head, epitems); if (!head->next) { head->next = tfile_check_list; tfile_check_list = head; } } static void unlist_file(struct epitems_head *head) { struct epitems_head *to_free = head; struct hlist_node *p = rcu_dereference(hlist_first_rcu(&head->epitems)); if (p) { struct epitem *epi= container_of(p, struct epitem, fllink); spin_lock(&epi->ffd.file->f_lock); if (!hlist_empty(&head->epitems)) to_free = NULL; head->next = NULL; spin_unlock(&epi->ffd.file->f_lock); } free_ephead(to_free); } |
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#ifdef CONFIG_SYSCTL #include <linux/sysctl.h> |
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static long long_zero; |
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static long long_max = LONG_MAX; |
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|
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struct ctl_table epoll_table[] = { |
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{ |
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.procname = "max_user_watches", .data = &max_user_watches, |
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.maxlen = sizeof(max_user_watches), |
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.mode = 0644, |
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.proc_handler = proc_doulongvec_minmax, |
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.extra1 = &long_zero, |
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.extra2 = &long_max, |
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}, |
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{ } |
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}; #endif /* CONFIG_SYSCTL */ |
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static const struct file_operations eventpoll_fops; static inline int is_file_epoll(struct file *f) { return f->f_op == &eventpoll_fops; } |
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/* Setup the structure that is used as key for the RB tree */ |
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static inline void ep_set_ffd(struct epoll_filefd *ffd, struct file *file, int fd) { ffd->file = file; ffd->fd = fd; } |
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/* Compare RB tree keys */ |
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static inline int ep_cmp_ffd(struct epoll_filefd *p1, struct epoll_filefd *p2) { return (p1->file > p2->file ? +1: (p1->file < p2->file ? -1 : p1->fd - p2->fd)); } |
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/* Tells us if the item is currently linked */ |
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static inline int ep_is_linked(struct epitem *epi) |
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{ |
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return !list_empty(&epi->rdllink); |
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} |
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static inline struct eppoll_entry *ep_pwq_from_wait(wait_queue_entry_t *p) |
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{ return container_of(p, struct eppoll_entry, wait); } |
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/* Get the "struct epitem" from a wait queue pointer */ |
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static inline struct epitem *ep_item_from_wait(wait_queue_entry_t *p) |
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{ return container_of(p, struct eppoll_entry, wait)->base; } |
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/** |
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* ep_events_available - Checks if ready events might be available. * * @ep: Pointer to the eventpoll context. * |
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* Return: a value different than %zero if ready events are available, * or %zero otherwise. |
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*/ static inline int ep_events_available(struct eventpoll *ep) { |
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return !list_empty_careful(&ep->rdllist) || READ_ONCE(ep->ovflist) != EP_UNACTIVE_PTR; |
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} |
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#ifdef CONFIG_NET_RX_BUSY_POLL static bool ep_busy_loop_end(void *p, unsigned long start_time) { struct eventpoll *ep = p; return ep_events_available(ep) || busy_loop_timeout(start_time); } |
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/* * Busy poll if globally on and supporting sockets found && no events, * busy loop will return if need_resched or ep_events_available. * * we must do our busy polling with irqs enabled */ |
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static bool ep_busy_loop(struct eventpoll *ep, int nonblock) |
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{ |
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unsigned int napi_id = READ_ONCE(ep->napi_id); |
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if ((napi_id >= MIN_NAPI_ID) && net_busy_loop_on()) { |
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napi_busy_loop(napi_id, nonblock ? NULL : ep_busy_loop_end, ep, false, BUSY_POLL_BUDGET); |
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if (ep_events_available(ep)) return true; /* * Busy poll timed out. Drop NAPI ID for now, we can add * it back in when we have moved a socket with a valid NAPI * ID onto the ready list. */ |
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ep->napi_id = 0; |
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return false; } return false; |
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} /* * Set epoll busy poll NAPI ID from sk. */ static inline void ep_set_busy_poll_napi_id(struct epitem *epi) { |
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struct eventpoll *ep; unsigned int napi_id; struct socket *sock; struct sock *sk; |
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if (!net_busy_loop_on()) return; |
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sock = sock_from_file(epi->ffd.file); |
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if (!sock) return; sk = sock->sk; if (!sk) return; napi_id = READ_ONCE(sk->sk_napi_id); ep = epi->ep; /* Non-NAPI IDs can be rejected * or * Nothing to do if we already have this ID */ if (napi_id < MIN_NAPI_ID || napi_id == ep->napi_id) return; /* record NAPI ID for use in next busy poll */ ep->napi_id = napi_id; |
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} |
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#else |
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static inline bool ep_busy_loop(struct eventpoll *ep, int nonblock) |
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{ |
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return false; |
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} static inline void ep_set_busy_poll_napi_id(struct epitem *epi) { } #endif /* CONFIG_NET_RX_BUSY_POLL */ |
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/* * As described in commit 0ccf831cb lockdep: annotate epoll * the use of wait queues used by epoll is done in a very controlled * manner. Wake ups can nest inside each other, but are never done * with the same locking. For example: * * dfd = socket(...); * efd1 = epoll_create(); * efd2 = epoll_create(); * epoll_ctl(efd1, EPOLL_CTL_ADD, dfd, ...); * epoll_ctl(efd2, EPOLL_CTL_ADD, efd1, ...); * * When a packet arrives to the device underneath "dfd", the net code will * issue a wake_up() on its poll wake list. Epoll (efd1) has installed a * callback wakeup entry on that queue, and the wake_up() performed by the * "dfd" net code will end up in ep_poll_callback(). At this point epoll * (efd1) notices that it may have some event ready, so it needs to wake up * the waiters on its poll wait list (efd2). So it calls ep_poll_safewake() * that ends up in another wake_up(), after having checked about the * recursion constraints. That are, no more than EP_MAX_POLLWAKE_NESTS, to * avoid stack blasting. * * When CONFIG_DEBUG_LOCK_ALLOC is enabled, make sure lockdep can handle * this special case of epoll. */ |
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#ifdef CONFIG_DEBUG_LOCK_ALLOC |
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|
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static void ep_poll_safewake(struct eventpoll *ep, struct epitem *epi) |
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{ |
efcdd350d fs/epoll: make ne... |
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struct eventpoll *ep_src; |
f6520c520 epoll: simplify e... |
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unsigned long flags; |
efcdd350d fs/epoll: make ne... |
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u8 nests = 0; /* * To set the subclass or nesting level for spin_lock_irqsave_nested() * it might be natural to create a per-cpu nest count. However, since * we can recurse on ep->poll_wait.lock, and a non-raw spinlock can * schedule() in the -rt kernel, the per-cpu variable are no longer * protected. Thus, we are introducing a per eventpoll nest field. * If we are not being call from ep_poll_callback(), epi is NULL and * we are at the first level of nesting, 0. Otherwise, we are being * called from ep_poll_callback() and if a previous wakeup source is * not an epoll file itself, we are at depth 1 since the wakeup source * is depth 0. If the wakeup source is a previous epoll file in the * wakeup chain then we use its nests value and record ours as * nests + 1. The previous epoll file nests value is stable since its * already holding its own poll_wait.lock. */ if (epi) { if ((is_file_epoll(epi->ffd.file))) { ep_src = epi->ffd.file->private_data; nests = ep_src->nests; } else { nests = 1; } } spin_lock_irqsave_nested(&ep->poll_wait.lock, flags, nests); ep->nests = nests + 1; wake_up_locked_poll(&ep->poll_wait, EPOLLIN); ep->nests = 0; spin_unlock_irqrestore(&ep->poll_wait.lock, flags); |
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} |
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#else |
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static void ep_poll_safewake(struct eventpoll *ep, struct epitem *epi) |
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{ |
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wake_up_poll(&ep->poll_wait, EPOLLIN); |
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497 498 499 |
} #endif |
971316f05 epoll: ep_unregis... |
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static void ep_remove_wait_queue(struct eppoll_entry *pwq) { wait_queue_head_t *whead; rcu_read_lock(); |
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/* * If it is cleared by POLLFREE, it should be rcu-safe. * If we read NULL we need a barrier paired with * smp_store_release() in ep_poll_callback(), otherwise * we rely on whead->lock. */ whead = smp_load_acquire(&pwq->whead); |
971316f05 epoll: ep_unregis... |
512 513 514 515 |
if (whead) remove_wait_queue(whead, &pwq->wait); rcu_read_unlock(); } |
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/* |
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* This function unregisters poll callbacks from the associated file * descriptor. Must be called with "mtx" held (or "epmutex" if called from * ep_free). |
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520 |
*/ |
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static void ep_unregister_pollwait(struct eventpoll *ep, struct epitem *epi) |
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{ |
80285b75c epoll: switch epi... |
523 |
struct eppoll_entry **p = &epi->pwqlist; |
7699acd13 epoll cleanups: e... |
524 |
struct eppoll_entry *pwq; |
1da177e4c Linux-2.6.12-rc2 |
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|
80285b75c epoll: switch epi... |
526 527 |
while ((pwq = *p) != NULL) { *p = pwq->next; |
971316f05 epoll: ep_unregis... |
528 |
ep_remove_wait_queue(pwq); |
d1bc90dd5 epoll: remove unn... |
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kmem_cache_free(pwq_cache, pwq); |
1da177e4c Linux-2.6.12-rc2 |
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} |
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} |
eea1d5859 epoll: use RCU to... |
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/* call only when ep->mtx is held */ static inline struct wakeup_source *ep_wakeup_source(struct epitem *epi) { return rcu_dereference_check(epi->ws, lockdep_is_held(&epi->ep->mtx)); } /* call only when ep->mtx is held */ static inline void ep_pm_stay_awake(struct epitem *epi) { struct wakeup_source *ws = ep_wakeup_source(epi); if (ws) __pm_stay_awake(ws); } static inline bool ep_has_wakeup_source(struct epitem *epi) { return rcu_access_pointer(epi->ws) ? true : false; } /* call when ep->mtx cannot be held (ep_poll_callback) */ static inline void ep_pm_stay_awake_rcu(struct epitem *epi) { struct wakeup_source *ws; rcu_read_lock(); ws = rcu_dereference(epi->ws); if (ws) __pm_stay_awake(ws); rcu_read_unlock(); } |
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|
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/* * ep->mutex needs to be held because we could be hit by * eventpoll_release_file() and epoll_ctl(). |
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*/ |
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static void ep_start_scan(struct eventpoll *ep, struct list_head *txlist) |
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{ |
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/* * Steal the ready list, and re-init the original one to the * empty list. Also, set ep->ovflist to NULL so that events * happening while looping w/out locks, are not lost. We cannot * have the poll callback to queue directly on ep->rdllist, * because we want the "sproc" callback to be able to do it * in a lockless way. */ |
57804b1cc lift locking/unlo... |
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lockdep_assert_irqs_enabled(); |
a218cc491 epoll: use rwlock... |
579 |
write_lock_irq(&ep->lock); |
db502f8a3 ep_scan_ready_lis... |
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list_splice_init(&ep->rdllist, txlist); |
c5a282e96 fs/epoll: reduce ... |
581 |
WRITE_ONCE(ep->ovflist, NULL); |
a218cc491 epoll: use rwlock... |
582 |
write_unlock_irq(&ep->lock); |
db502f8a3 ep_scan_ready_lis... |
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} |
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|
db502f8a3 ep_scan_ready_lis... |
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static void ep_done_scan(struct eventpoll *ep, |
db502f8a3 ep_scan_ready_lis... |
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struct list_head *txlist) { struct epitem *epi, *nepi; |
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589 |
|
a218cc491 epoll: use rwlock... |
590 |
write_lock_irq(&ep->lock); |
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/* * During the time we spent inside the "sproc" callback, some * other events might have been queued by the poll callback. * We re-insert them inside the main ready-list here. */ |
c5a282e96 fs/epoll: reduce ... |
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for (nepi = READ_ONCE(ep->ovflist); (epi = nepi) != NULL; |
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597 598 599 600 601 602 603 |
nepi = epi->next, epi->next = EP_UNACTIVE_PTR) { /* * We need to check if the item is already in the list. * During the "sproc" callback execution time, items are * queued into ->ovflist but the "txlist" might already * contain them, and the list_splice() below takes care of them. */ |
992991c03 fs/eventpoll.c: s... |
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if (!ep_is_linked(epi)) { |
c141175d0 epoll: make sure ... |
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/* * ->ovflist is LIFO, so we have to reverse it in order * to keep in FIFO. */ list_add(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
610 |
ep_pm_stay_awake(epi); |
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} |
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} /* * We need to set back ep->ovflist to EP_UNACTIVE_PTR, so that after * releasing the lock, events will be queued in the normal way inside * ep->rdllist. */ |
c5a282e96 fs/epoll: reduce ... |
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WRITE_ONCE(ep->ovflist, EP_UNACTIVE_PTR); |
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/* * Quickly re-inject items left on "txlist". */ |
db502f8a3 ep_scan_ready_lis... |
623 |
list_splice(txlist, &ep->rdllist); |
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624 |
__pm_relax(ep->ws); |
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if (!list_empty(&ep->rdllist)) { if (waitqueue_active(&ep->wq)) wake_up(&ep->wq); } |
a218cc491 epoll: use rwlock... |
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write_unlock_irq(&ep->lock); |
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} |
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static void epi_rcu_free(struct rcu_head *head) { struct epitem *epi = container_of(head, struct epitem, rcu); kmem_cache_free(epi_cache, epi); } |
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/* |
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* Removes a "struct epitem" from the eventpoll RB tree and deallocates |
c7ea76302 epoll locks chang... |
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* all the associated resources. Must be called with "mtx" held. |
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*/ static int ep_remove(struct eventpoll *ep, struct epitem *epi) { |
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struct file *file = epi->ffd.file; |
319c15174 epoll: take epite... |
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struct epitems_head *to_free; struct hlist_head *head; |
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|
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lockdep_assert_irqs_enabled(); |
1da177e4c Linux-2.6.12-rc2 |
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/* |
ee8ef0a4b epoll: use the wa... |
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* Removes poll wait queue hooks. |
1da177e4c Linux-2.6.12-rc2 |
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*/ |
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ep_unregister_pollwait(ep, epi); |
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|
7699acd13 epoll cleanups: e... |
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/* Remove the current item from the list of epoll hooks */ |
684999149 Rename struct fil... |
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spin_lock(&file->f_lock); |
319c15174 epoll: take epite... |
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to_free = NULL; head = file->f_ep; if (head->first == &epi->fllink && !epi->fllink.next) { file->f_ep = NULL; if (!is_file_epoll(file)) { struct epitems_head *v; v = container_of(head, struct epitems_head, epitems); if (!smp_load_acquire(&v->next)) to_free = v; } } |
44cdc1d95 convert ->f_ep_li... |
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hlist_del_rcu(&epi->fllink); |
684999149 Rename struct fil... |
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spin_unlock(&file->f_lock); |
319c15174 epoll: take epite... |
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free_ephead(to_free); |
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|
b2ac2ea62 fs/epoll: use fas... |
670 |
rb_erase_cached(&epi->rbn, &ep->rbr); |
1da177e4c Linux-2.6.12-rc2 |
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|
a218cc491 epoll: use rwlock... |
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write_lock_irq(&ep->lock); |
992991c03 fs/eventpoll.c: s... |
673 |
if (ep_is_linked(epi)) |
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list_del_init(&epi->rdllink); |
a218cc491 epoll: use rwlock... |
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write_unlock_irq(&ep->lock); |
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|
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wakeup_source_unregister(ep_wakeup_source(epi)); |
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/* * At this point it is safe to free the eventpoll item. Use the union * field epi->rcu, since we are trying to minimize the size of * 'struct epitem'. The 'rbn' field is no longer in use. Protected by * ep->mtx. The rcu read side, reverse_path_check_proc(), does not make * use of the rbn field. */ call_rcu(&epi->rcu, epi_rcu_free); |
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|
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percpu_counter_dec(&ep->user->epoll_watches); |
7ef9964e6 epoll: introduce ... |
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|
c7ea76302 epoll locks chang... |
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return 0; |
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690 |
} |
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static void ep_free(struct eventpoll *ep) |
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{ |
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struct rb_node *rbp; struct epitem *epi; |
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|
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/* We need to release all tasks waiting for these file */ if (waitqueue_active(&ep->poll_wait)) |
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ep_poll_safewake(ep, NULL); |
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|
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/* * We need to lock this because we could be hit by * eventpoll_release_file() while we're freeing the "struct eventpoll". |
d47de16c7 fix epoll single ... |
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* We do not need to hold "ep->mtx" here because the epoll file |
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* is on the way to be removed and no one has references to it * anymore. The only hit might come from eventpoll_release_file() but |
25985edce Fix common misspe... |
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* holding "epmutex" is sufficient here. |
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*/ mutex_lock(&epmutex); |
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/* |
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* Walks through the whole tree by unregistering poll callbacks. |
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*/ |
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for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
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epi = rb_entry(rbp, struct epitem, rbn); ep_unregister_pollwait(ep, epi); |
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cond_resched(); |
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} |
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/* |
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721 722 |
* Walks through the whole tree by freeing each "struct epitem". At this * point we are sure no poll callbacks will be lingering around, and also by |
d47de16c7 fix epoll single ... |
723 |
* holding "epmutex" we can be sure that no file cleanup code will hit |
a218cc491 epoll: use rwlock... |
724 |
* us during this operation. So we can avoid the lock on "ep->lock". |
ddf676c38 epoll: lock ep->m... |
725 726 |
* We do not need to lock ep->mtx, either, we only do it to prevent * a lockdep warning. |
1da177e4c Linux-2.6.12-rc2 |
727 |
*/ |
ddf676c38 epoll: lock ep->m... |
728 |
mutex_lock(&ep->mtx); |
b2ac2ea62 fs/epoll: use fas... |
729 |
while ((rbp = rb_first_cached(&ep->rbr)) != NULL) { |
7699acd13 epoll cleanups: e... |
730 731 |
epi = rb_entry(rbp, struct epitem, rbn); ep_remove(ep, epi); |
91cf5ab60 epoll: add a resc... |
732 |
cond_resched(); |
7699acd13 epoll cleanups: e... |
733 |
} |
ddf676c38 epoll: lock ep->m... |
734 |
mutex_unlock(&ep->mtx); |
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735 |
|
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736 |
mutex_unlock(&epmutex); |
d47de16c7 fix epoll single ... |
737 |
mutex_destroy(&ep->mtx); |
7ef9964e6 epoll: introduce ... |
738 |
free_uid(ep->user); |
4d7e30d98 epoll: Add a flag... |
739 |
wakeup_source_unregister(ep->ws); |
f0ee9aabb epoll: move kfree... |
740 |
kfree(ep); |
7699acd13 epoll cleanups: e... |
741 |
} |
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742 |
|
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743 744 745 |
static int ep_eventpoll_release(struct inode *inode, struct file *file) { struct eventpoll *ep = file->private_data; |
1da177e4c Linux-2.6.12-rc2 |
746 |
|
f0ee9aabb epoll: move kfree... |
747 |
if (ep) |
7699acd13 epoll cleanups: e... |
748 |
ep_free(ep); |
7699acd13 epoll cleanups: e... |
749 |
|
7699acd13 epoll cleanups: e... |
750 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
751 |
} |
2c0b71c1e fold ep_read_even... |
752 |
static __poll_t ep_item_poll(const struct epitem *epi, poll_table *pt, int depth); |
37b5e5212 epoll: remove ep_... |
753 |
|
ad9366b13 take the common p... |
754 |
static __poll_t __ep_eventpoll_poll(struct file *file, poll_table *wait, int depth) |
5071f97ec epoll: fix epoll'... |
755 |
{ |
ad9366b13 take the common p... |
756 757 |
struct eventpoll *ep = file->private_data; LIST_HEAD(txlist); |
5071f97ec epoll: fix epoll'... |
758 |
struct epitem *epi, *tmp; |
626cf2366 poll: add poll_re... |
759 |
poll_table pt; |
2c0b71c1e fold ep_read_even... |
760 |
__poll_t res = 0; |
5071f97ec epoll: fix epoll'... |
761 |
|
626cf2366 poll: add poll_re... |
762 |
init_poll_funcptr(&pt, NULL); |
450d89ec0 epoll: cleanup: h... |
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|
ad9366b13 take the common p... |
764 765 766 767 768 769 770 771 772 |
/* Insert inside our poll wait queue */ poll_wait(file, &ep->poll_wait, wait); /* * Proceed to find out if wanted events are really available inside * the ready list. */ mutex_lock_nested(&ep->mtx, depth); ep_start_scan(ep, &txlist); |
2c0b71c1e fold ep_read_even... |
773 774 775 776 |
list_for_each_entry_safe(epi, tmp, &txlist, rdllink) { if (ep_item_poll(epi, &pt, depth + 1)) { res = EPOLLIN | EPOLLRDNORM; break; |
37b5e5212 epoll: remove ep_... |
777 |
} else { |
5071f97ec epoll: fix epoll'... |
778 779 780 781 782 |
/* * Item has been dropped into the ready list by the poll * callback, but it's not actually ready, as far as * caller requested events goes. We can remove it here. */ |
eea1d5859 epoll: use RCU to... |
783 |
__pm_relax(ep_wakeup_source(epi)); |
5071f97ec epoll: fix epoll'... |
784 |
list_del_init(&epi->rdllink); |
296e236e9 epoll: fix epoll'... |
785 |
} |
5071f97ec epoll: fix epoll'... |
786 |
} |
ad9366b13 take the common p... |
787 788 789 |
ep_done_scan(ep, &txlist); mutex_unlock(&ep->mtx); return res; |
5071f97ec epoll: fix epoll'... |
790 |
} |
37b5e5212 epoll: remove ep_... |
791 792 793 794 795 |
/* * Differs from ep_eventpoll_poll() in that internal callers already have * the ep->mtx so we need to start from depth=1, such that mutex_lock_nested() * is correctly annotated. */ |
d85e2aa2e annotate ep_scan_... |
796 |
static __poll_t ep_item_poll(const struct epitem *epi, poll_table *pt, |
bec1a502d eventpoll: consti... |
797 |
int depth) |
11c5ad0ec eventpoll: switch... |
798 |
{ |
ad9366b13 take the common p... |
799 |
struct file *file = epi->ffd.file; |
1ec09974d lift the calls of... |
800 |
__poll_t res; |
7699acd13 epoll cleanups: e... |
801 |
|
450d89ec0 epoll: cleanup: h... |
802 |
pt->_key = epi->event.events; |
ad9366b13 take the common p... |
803 804 805 806 |
if (!is_file_epoll(file)) res = vfs_poll(file, pt); else res = __ep_eventpoll_poll(file, pt, depth); |
1ec09974d lift the calls of... |
807 |
return res & epi->event.events; |
450d89ec0 epoll: cleanup: h... |
808 |
} |
a11e1d432 Revert changes to... |
809 |
|
a11e1d432 Revert changes to... |
810 |
static __poll_t ep_eventpoll_poll(struct file *file, poll_table *wait) |
11c5ad0ec eventpoll: switch... |
811 |
{ |
ad9366b13 take the common p... |
812 |
return __ep_eventpoll_poll(file, wait, 0); |
7699acd13 epoll cleanups: e... |
813 |
} |
138d22b58 fs, epoll: add pr... |
814 |
#ifdef CONFIG_PROC_FS |
a3816ab0e fs: Convert show_... |
815 |
static void ep_show_fdinfo(struct seq_file *m, struct file *f) |
138d22b58 fs, epoll: add pr... |
816 817 818 |
{ struct eventpoll *ep = f->private_data; struct rb_node *rbp; |
138d22b58 fs, epoll: add pr... |
819 820 |
mutex_lock(&ep->mtx); |
b2ac2ea62 fs/epoll: use fas... |
821 |
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
138d22b58 fs, epoll: add pr... |
822 |
struct epitem *epi = rb_entry(rbp, struct epitem, rbn); |
77493f04b procfs: fdinfo: e... |
823 |
struct inode *inode = file_inode(epi->ffd.file); |
138d22b58 fs, epoll: add pr... |
824 |
|
77493f04b procfs: fdinfo: e... |
825 826 827 |
seq_printf(m, "tfd: %8d events: %8x data: %16llx " " pos:%lli ino:%lx sdev:%x ", |
a3816ab0e fs: Convert show_... |
828 |
epi->ffd.fd, epi->event.events, |
77493f04b procfs: fdinfo: e... |
829 830 831 |
(long long)epi->event.data, (long long)epi->ffd.file->f_pos, inode->i_ino, inode->i_sb->s_dev); |
a3816ab0e fs: Convert show_... |
832 |
if (seq_has_overflowed(m)) |
138d22b58 fs, epoll: add pr... |
833 834 835 |
break; } mutex_unlock(&ep->mtx); |
138d22b58 fs, epoll: add pr... |
836 837 |
} #endif |
7699acd13 epoll cleanups: e... |
838 839 |
/* File callbacks that implement the eventpoll file behaviour */ static const struct file_operations eventpoll_fops = { |
138d22b58 fs, epoll: add pr... |
840 841 842 |
#ifdef CONFIG_PROC_FS .show_fdinfo = ep_show_fdinfo, #endif |
7699acd13 epoll cleanups: e... |
843 |
.release = ep_eventpoll_release, |
a11e1d432 Revert changes to... |
844 |
.poll = ep_eventpoll_poll, |
6038f373a llseek: automatic... |
845 |
.llseek = noop_llseek, |
7699acd13 epoll cleanups: e... |
846 |
}; |
b611967de [PATCH] epoll_pwa... |
847 |
/* |
7699acd13 epoll cleanups: e... |
848 849 850 |
* This is called from eventpoll_release() to unlink files from the eventpoll * interface. We need to have this facility to cleanup correctly files that are * closed without being removed from the eventpoll interface. |
b611967de [PATCH] epoll_pwa... |
851 |
*/ |
7699acd13 epoll cleanups: e... |
852 |
void eventpoll_release_file(struct file *file) |
b611967de [PATCH] epoll_pwa... |
853 |
{ |
7699acd13 epoll cleanups: e... |
854 |
struct eventpoll *ep; |
44cdc1d95 convert ->f_ep_li... |
855 856 |
struct epitem *epi; struct hlist_node *next; |
b611967de [PATCH] epoll_pwa... |
857 858 |
/* |
684999149 Rename struct fil... |
859 |
* We don't want to get "file->f_lock" because it is not |
7699acd13 epoll cleanups: e... |
860 |
* necessary. It is not necessary because we're in the "struct file" |
25985edce Fix common misspe... |
861 |
* cleanup path, and this means that no one is using this file anymore. |
5071f97ec epoll: fix epoll'... |
862 |
* So, for example, epoll_ctl() cannot hit here since if we reach this |
67647d0fb epoll: fix some c... |
863 |
* point, the file counter already went to zero and fget() would fail. |
d47de16c7 fix epoll single ... |
864 |
* The only hit might come from ep_free() but by holding the mutex |
7699acd13 epoll cleanups: e... |
865 |
* will correctly serialize the operation. We do need to acquire |
d47de16c7 fix epoll single ... |
866 |
* "ep->mtx" after "epmutex" because ep_remove() requires it when called |
7699acd13 epoll cleanups: e... |
867 |
* from anywhere but ep_free(). |
684999149 Rename struct fil... |
868 869 |
* * Besides, ep_remove() acquires the lock, so we can't hold it here. |
b611967de [PATCH] epoll_pwa... |
870 |
*/ |
7699acd13 epoll cleanups: e... |
871 |
mutex_lock(&epmutex); |
319c15174 epoll: take epite... |
872 873 874 875 876 |
if (unlikely(!file->f_ep)) { mutex_unlock(&epmutex); return; } hlist_for_each_entry_safe(epi, next, file->f_ep, fllink) { |
7699acd13 epoll cleanups: e... |
877 |
ep = epi->ep; |
d8805e633 epoll: fix spurio... |
878 |
mutex_lock_nested(&ep->mtx, 0); |
7699acd13 epoll cleanups: e... |
879 |
ep_remove(ep, epi); |
d47de16c7 fix epoll single ... |
880 |
mutex_unlock(&ep->mtx); |
b611967de [PATCH] epoll_pwa... |
881 |
} |
7699acd13 epoll cleanups: e... |
882 |
mutex_unlock(&epmutex); |
b611967de [PATCH] epoll_pwa... |
883 |
} |
53d2be79d [PATCH] epoll: fi... |
884 |
static int ep_alloc(struct eventpoll **pep) |
1da177e4c Linux-2.6.12-rc2 |
885 |
{ |
7ef9964e6 epoll: introduce ... |
886 887 888 |
int error; struct user_struct *user; struct eventpoll *ep; |
1da177e4c Linux-2.6.12-rc2 |
889 |
|
7ef9964e6 epoll: introduce ... |
890 |
user = get_current_user(); |
7ef9964e6 epoll: introduce ... |
891 892 893 894 |
error = -ENOMEM; ep = kzalloc(sizeof(*ep), GFP_KERNEL); if (unlikely(!ep)) goto free_uid; |
1da177e4c Linux-2.6.12-rc2 |
895 |
|
d47de16c7 fix epoll single ... |
896 |
mutex_init(&ep->mtx); |
a218cc491 epoll: use rwlock... |
897 |
rwlock_init(&ep->lock); |
1da177e4c Linux-2.6.12-rc2 |
898 899 900 |
init_waitqueue_head(&ep->wq); init_waitqueue_head(&ep->poll_wait); INIT_LIST_HEAD(&ep->rdllist); |
b2ac2ea62 fs/epoll: use fas... |
901 |
ep->rbr = RB_ROOT_CACHED; |
d47de16c7 fix epoll single ... |
902 |
ep->ovflist = EP_UNACTIVE_PTR; |
7ef9964e6 epoll: introduce ... |
903 |
ep->user = user; |
1da177e4c Linux-2.6.12-rc2 |
904 |
|
53d2be79d [PATCH] epoll: fi... |
905 |
*pep = ep; |
1da177e4c Linux-2.6.12-rc2 |
906 |
|
1da177e4c Linux-2.6.12-rc2 |
907 |
return 0; |
7ef9964e6 epoll: introduce ... |
908 909 910 911 |
free_uid: free_uid(user); return error; |
1da177e4c Linux-2.6.12-rc2 |
912 |
} |
1da177e4c Linux-2.6.12-rc2 |
913 |
/* |
c7ea76302 epoll locks chang... |
914 915 916 |
* Search the file inside the eventpoll tree. The RB tree operations * are protected by the "mtx" mutex, and ep_find() must be called with * "mtx" held. |
1da177e4c Linux-2.6.12-rc2 |
917 918 919 920 |
*/ static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd) { int kcmp; |
1da177e4c Linux-2.6.12-rc2 |
921 922 923 |
struct rb_node *rbp; struct epitem *epi, *epir = NULL; struct epoll_filefd ffd; |
b030a4dd6 [PATCH] Remove ev... |
924 |
ep_set_ffd(&ffd, file, fd); |
b2ac2ea62 fs/epoll: use fas... |
925 |
for (rbp = ep->rbr.rb_root.rb_node; rbp; ) { |
1da177e4c Linux-2.6.12-rc2 |
926 |
epi = rb_entry(rbp, struct epitem, rbn); |
b030a4dd6 [PATCH] Remove ev... |
927 |
kcmp = ep_cmp_ffd(&ffd, &epi->ffd); |
1da177e4c Linux-2.6.12-rc2 |
928 929 930 931 932 |
if (kcmp > 0) rbp = rbp->rb_right; else if (kcmp < 0) rbp = rbp->rb_left; else { |
1da177e4c Linux-2.6.12-rc2 |
933 934 935 936 |
epir = epi; break; } } |
1da177e4c Linux-2.6.12-rc2 |
937 |
|
1da177e4c Linux-2.6.12-rc2 |
938 939 |
return epir; } |
bfe3911a9 kcmp: Support sel... |
940 |
#ifdef CONFIG_KCMP |
0791e3644 kcmp: add KCMP_EP... |
941 942 943 944 |
static struct epitem *ep_find_tfd(struct eventpoll *ep, int tfd, unsigned long toff) { struct rb_node *rbp; struct epitem *epi; |
b2ac2ea62 fs/epoll: use fas... |
945 |
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
0791e3644 kcmp: add KCMP_EP... |
946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 |
epi = rb_entry(rbp, struct epitem, rbn); if (epi->ffd.fd == tfd) { if (toff == 0) return epi; else toff--; } cond_resched(); } return NULL; } struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long toff) { struct file *file_raw; struct eventpoll *ep; struct epitem *epi; if (!is_file_epoll(file)) return ERR_PTR(-EINVAL); ep = file->private_data; mutex_lock(&ep->mtx); epi = ep_find_tfd(ep, tfd, toff); if (epi) file_raw = epi->ffd.file; else file_raw = ERR_PTR(-ENOENT); mutex_unlock(&ep->mtx); return file_raw; } |
bfe3911a9 kcmp: Support sel... |
981 |
#endif /* CONFIG_KCMP */ |
0791e3644 kcmp: add KCMP_EP... |
982 |
|
a6c67fee9 fs: eventpoll: fi... |
983 |
/* |
a218cc491 epoll: use rwlock... |
984 985 986 987 988 989 990 991 992 993 994 |
* Adds a new entry to the tail of the list in a lockless way, i.e. * multiple CPUs are allowed to call this function concurrently. * * Beware: it is necessary to prevent any other modifications of the * existing list until all changes are completed, in other words * concurrent list_add_tail_lockless() calls should be protected * with a read lock, where write lock acts as a barrier which * makes sure all list_add_tail_lockless() calls are fully * completed. * * Also an element can be locklessly added to the list only in one |
a6c67fee9 fs: eventpoll: fi... |
995 |
* direction i.e. either to the tail or to the head, otherwise |
a218cc491 epoll: use rwlock... |
996 997 |
* concurrent access will corrupt the list. * |
a6c67fee9 fs: eventpoll: fi... |
998 |
* Return: %false if element has been already added to the list, %true |
a218cc491 epoll: use rwlock... |
999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 |
* otherwise. */ static inline bool list_add_tail_lockless(struct list_head *new, struct list_head *head) { struct list_head *prev; /* * This is simple 'new->next = head' operation, but cmpxchg() * is used in order to detect that same element has been just * added to the list from another CPU: the winner observes * new->next == new. */ if (cmpxchg(&new->next, new, head) != new) return false; /* * Initially ->next of a new element must be updated with the head * (we are inserting to the tail) and only then pointers are atomically * exchanged. XCHG guarantees memory ordering, thus ->next should be * updated before pointers are actually swapped and pointers are * swapped before prev->next is updated. */ prev = xchg(&head->prev, new); /* * It is safe to modify prev->next and new->prev, because a new element * is added only to the tail and new->next is updated before XCHG. */ prev->next = new; new->prev = prev; return true; } |
a6c67fee9 fs: eventpoll: fi... |
1035 |
/* |
a218cc491 epoll: use rwlock... |
1036 1037 1038 |
* Chains a new epi entry to the tail of the ep->ovflist in a lockless way, * i.e. multiple CPUs are allowed to call this function concurrently. * |
a6c67fee9 fs: eventpoll: fi... |
1039 |
* Return: %false if epi element has been already chained, %true otherwise. |
a218cc491 epoll: use rwlock... |
1040 1041 1042 1043 |
*/ static inline bool chain_epi_lockless(struct epitem *epi) { struct eventpoll *ep = epi->ep; |
0c54a6a44 eventpoll: fix mi... |
1044 1045 1046 |
/* Fast preliminary check */ if (epi->next != EP_UNACTIVE_PTR) return false; |
a218cc491 epoll: use rwlock... |
1047 1048 1049 1050 1051 1052 1053 1054 1055 |
/* Check that the same epi has not been just chained from another CPU */ if (cmpxchg(&epi->next, EP_UNACTIVE_PTR, NULL) != EP_UNACTIVE_PTR) return false; /* Atomically exchange tail */ epi->next = xchg(&ep->ovflist, epi); return true; } |
1da177e4c Linux-2.6.12-rc2 |
1056 |
/* |
7699acd13 epoll cleanups: e... |
1057 |
* This is the callback that is passed to the wait queue wakeup |
bf6a41db7 fs/eventpoll.c: f... |
1058 |
* mechanism. It is called by the stored file descriptors when they |
7699acd13 epoll cleanups: e... |
1059 |
* have events to report. |
a218cc491 epoll: use rwlock... |
1060 |
* |
a6c67fee9 fs: eventpoll: fi... |
1061 1062 |
* This callback takes a read lock in order not to contend with concurrent * events from another file descriptor, thus all modifications to ->rdllist |
a218cc491 epoll: use rwlock... |
1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 |
* or ->ovflist are lockless. Read lock is paired with the write lock from * ep_scan_ready_list(), which stops all list modifications and guarantees * that lists state is seen correctly. * * Another thing worth to mention is that ep_poll_callback() can be called * concurrently for the same @epi from different CPUs if poll table was inited * with several wait queues entries. Plural wakeup from different CPUs of a * single wait queue is serialized by wq.lock, but the case when multiple wait * queues are used should be detected accordingly. This is detected using * cmpxchg() operation. |
1da177e4c Linux-2.6.12-rc2 |
1073 |
*/ |
ac6424b98 sched/wait: Renam... |
1074 |
static int ep_poll_callback(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) |
1da177e4c Linux-2.6.12-rc2 |
1075 |
{ |
7699acd13 epoll cleanups: e... |
1076 |
int pwake = 0; |
7699acd13 epoll cleanups: e... |
1077 1078 |
struct epitem *epi = ep_item_from_wait(wait); struct eventpoll *ep = epi->ep; |
3ad6f93e9 annotate poll-rel... |
1079 |
__poll_t pollflags = key_to_poll(key); |
a218cc491 epoll: use rwlock... |
1080 |
unsigned long flags; |
df0108c5d epoll: add EPOLLE... |
1081 |
int ewake = 0; |
1da177e4c Linux-2.6.12-rc2 |
1082 |
|
a218cc491 epoll: use rwlock... |
1083 |
read_lock_irqsave(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1084 |
|
bf3b9f637 epoll: Add busy p... |
1085 |
ep_set_busy_poll_napi_id(epi); |
7699acd13 epoll cleanups: e... |
1086 1087 1088 1089 1090 1091 1092 |
/* * If the event mask does not contain any poll(2) event, we consider the * descriptor to be disabled. This condition is likely the effect of the * EPOLLONESHOT bit that disables the descriptor when an event is received, * until the next EPOLL_CTL_MOD will be issued. */ if (!(epi->event.events & ~EP_PRIVATE_BITS)) |
d47de16c7 fix epoll single ... |
1093 1094 1095 |
goto out_unlock; /* |
2dfa4eeab epoll keyed wakeu... |
1096 1097 1098 1099 1100 |
* Check the events coming with the callback. At this stage, not * every device reports the events in the "key" parameter of the * callback. We need to be able to handle both cases here, hence the * test for "key" != NULL before the event match test. */ |
3ad6f93e9 annotate poll-rel... |
1101 |
if (pollflags && !(pollflags & epi->event.events)) |
2dfa4eeab epoll keyed wakeu... |
1102 1103 1104 |
goto out_unlock; /* |
bf6a41db7 fs/eventpoll.c: f... |
1105 |
* If we are transferring events to userspace, we can hold no locks |
d47de16c7 fix epoll single ... |
1106 |
* (because we're accessing user memory, and because of linux f_op->poll() |
bf6a41db7 fs/eventpoll.c: f... |
1107 |
* semantics). All the events that happen during that period of time are |
d47de16c7 fix epoll single ... |
1108 1109 |
* chained in ep->ovflist and requeued later on. */ |
c5a282e96 fs/epoll: reduce ... |
1110 |
if (READ_ONCE(ep->ovflist) != EP_UNACTIVE_PTR) { |
0c54a6a44 eventpoll: fix mi... |
1111 1112 1113 1114 1115 |
if (chain_epi_lockless(epi)) ep_pm_stay_awake_rcu(epi); } else if (!ep_is_linked(epi)) { /* In the usual case, add event to ready list. */ if (list_add_tail_lockless(&epi->rdllink, &ep->rdllist)) |
c3e320b61 epoll: unify awak... |
1116 |
ep_pm_stay_awake_rcu(epi); |
4d7e30d98 epoll: Add a flag... |
1117 |
} |
7699acd13 epoll cleanups: e... |
1118 |
|
7699acd13 epoll cleanups: e... |
1119 1120 1121 1122 |
/* * Wake up ( if active ) both the eventpoll wait list and the ->poll() * wait list. */ |
df0108c5d epoll: add EPOLLE... |
1123 |
if (waitqueue_active(&ep->wq)) { |
b6a515c8a epoll: restrict E... |
1124 |
if ((epi->event.events & EPOLLEXCLUSIVE) && |
3ad6f93e9 annotate poll-rel... |
1125 1126 |
!(pollflags & POLLFREE)) { switch (pollflags & EPOLLINOUT_BITS) { |
a9a08845e vfs: do bulk POLL... |
1127 1128 |
case EPOLLIN: if (epi->event.events & EPOLLIN) |
b6a515c8a epoll: restrict E... |
1129 1130 |
ewake = 1; break; |
a9a08845e vfs: do bulk POLL... |
1131 1132 |
case EPOLLOUT: if (epi->event.events & EPOLLOUT) |
b6a515c8a epoll: restrict E... |
1133 1134 1135 1136 1137 1138 1139 |
ewake = 1; break; case 0: ewake = 1; break; } } |
a218cc491 epoll: use rwlock... |
1140 |
wake_up(&ep->wq); |
df0108c5d epoll: add EPOLLE... |
1141 |
} |
7699acd13 epoll cleanups: e... |
1142 1143 |
if (waitqueue_active(&ep->poll_wait)) pwake++; |
d47de16c7 fix epoll single ... |
1144 |
out_unlock: |
a218cc491 epoll: use rwlock... |
1145 |
read_unlock_irqrestore(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1146 |
|
7699acd13 epoll cleanups: e... |
1147 1148 |
/* We have to call this outside the lock */ if (pwake) |
efcdd350d fs/epoll: make ne... |
1149 |
ep_poll_safewake(ep, epi); |
7699acd13 epoll cleanups: e... |
1150 |
|
138e4ad67 epoll: fix race b... |
1151 1152 |
if (!(epi->event.events & EPOLLEXCLUSIVE)) ewake = 1; |
3ad6f93e9 annotate poll-rel... |
1153 |
if (pollflags & POLLFREE) { |
138e4ad67 epoll: fix race b... |
1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 |
/* * If we race with ep_remove_wait_queue() it can miss * ->whead = NULL and do another remove_wait_queue() after * us, so we can't use __remove_wait_queue(). */ list_del_init(&wait->entry); /* * ->whead != NULL protects us from the race with ep_free() * or ep_remove(), ep_remove_wait_queue() takes whead->lock * held by the caller. Once we nullify it, nothing protects * ep/epi or even wait. */ smp_store_release(&ep_pwq_from_wait(wait)->whead, NULL); } |
df0108c5d epoll: add EPOLLE... |
1168 |
|
138e4ad67 epoll: fix race b... |
1169 |
return ewake; |
7699acd13 epoll cleanups: e... |
1170 |
} |
1da177e4c Linux-2.6.12-rc2 |
1171 1172 1173 1174 1175 1176 1177 1178 |
/* * This is the callback that is used to add our wait queue to the * target file wakeup lists. */ static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead, poll_table *pt) { |
364f374f2 epoll: get rid of... |
1179 1180 |
struct ep_pqueue *epq = container_of(pt, struct ep_pqueue, pt); struct epitem *epi = epq->epi; |
1da177e4c Linux-2.6.12-rc2 |
1181 |
struct eppoll_entry *pwq; |
364f374f2 epoll: get rid of... |
1182 1183 1184 1185 1186 1187 1188 |
if (unlikely(!epi)) // an earlier allocation has failed return; pwq = kmem_cache_alloc(pwq_cache, GFP_KERNEL); if (unlikely(!pwq)) { epq->epi = NULL; return; |
296e236e9 epoll: fix epoll'... |
1189 |
} |
364f374f2 epoll: get rid of... |
1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 |
init_waitqueue_func_entry(&pwq->wait, ep_poll_callback); pwq->whead = whead; pwq->base = epi; if (epi->event.events & EPOLLEXCLUSIVE) add_wait_queue_exclusive(whead, &pwq->wait); else add_wait_queue(whead, &pwq->wait); pwq->next = epi->pwqlist; epi->pwqlist = pwq; |
1da177e4c Linux-2.6.12-rc2 |
1200 |
} |
1da177e4c Linux-2.6.12-rc2 |
1201 1202 1203 |
static void ep_rbtree_insert(struct eventpoll *ep, struct epitem *epi) { int kcmp; |
b2ac2ea62 fs/epoll: use fas... |
1204 |
struct rb_node **p = &ep->rbr.rb_root.rb_node, *parent = NULL; |
1da177e4c Linux-2.6.12-rc2 |
1205 |
struct epitem *epic; |
b2ac2ea62 fs/epoll: use fas... |
1206 |
bool leftmost = true; |
1da177e4c Linux-2.6.12-rc2 |
1207 1208 1209 1210 |
while (*p) { parent = *p; epic = rb_entry(parent, struct epitem, rbn); |
b030a4dd6 [PATCH] Remove ev... |
1211 |
kcmp = ep_cmp_ffd(&epi->ffd, &epic->ffd); |
b2ac2ea62 fs/epoll: use fas... |
1212 |
if (kcmp > 0) { |
1da177e4c Linux-2.6.12-rc2 |
1213 |
p = &parent->rb_right; |
b2ac2ea62 fs/epoll: use fas... |
1214 1215 |
leftmost = false; } else |
1da177e4c Linux-2.6.12-rc2 |
1216 1217 1218 |
p = &parent->rb_left; } rb_link_node(&epi->rbn, parent, p); |
b2ac2ea62 fs/epoll: use fas... |
1219 |
rb_insert_color_cached(&epi->rbn, &ep->rbr, leftmost); |
1da177e4c Linux-2.6.12-rc2 |
1220 |
} |
a80a6b85b revert "epoll: su... |
1221 |
|
28d82dc1c epoll: limit paths |
1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 |
#define PATH_ARR_SIZE 5 /* * These are the number paths of length 1 to 5, that we are allowing to emanate * from a single file of interest. For example, we allow 1000 paths of length * 1, to emanate from each file of interest. This essentially represents the * potential wakeup paths, which need to be limited in order to avoid massive * uncontrolled wakeup storms. The common use case should be a single ep which * is connected to n file sources. In this case each file source has 1 path * of length 1. Thus, the numbers below should be more than sufficient. These * path limits are enforced during an EPOLL_CTL_ADD operation, since a modify * and delete can't add additional paths. Protected by the epmutex. */ static const int path_limits[PATH_ARR_SIZE] = { 1000, 500, 100, 50, 10 }; static int path_count[PATH_ARR_SIZE]; static int path_count_inc(int nests) { |
93dc6107a Don't limit non-n... |
1239 1240 1241 |
/* Allow an arbitrary number of depth 1 paths */ if (nests == 0) return 0; |
28d82dc1c epoll: limit paths |
1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 |
if (++path_count[nests] > path_limits[nests]) return -1; return 0; } static void path_count_init(void) { int i; for (i = 0; i < PATH_ARR_SIZE; i++) path_count[i] = 0; } |
319c15174 epoll: take epite... |
1254 |
static int reverse_path_check_proc(struct hlist_head *refs, int depth) |
28d82dc1c epoll: limit paths |
1255 1256 |
{ int error = 0; |
28d82dc1c epoll: limit paths |
1257 |
struct epitem *epi; |
0c320f776 reverse_path_chec... |
1258 |
if (depth > EP_MAX_NESTS) /* too deep nesting */ |
99d84d433 untangling ep_cal... |
1259 |
return -1; |
ae10b2b4e epoll: optimize E... |
1260 |
/* CTL_DEL can remove links here, but that can't increase our count */ |
319c15174 epoll: take epite... |
1261 1262 1263 |
hlist_for_each_entry_rcu(epi, refs, fllink) { struct hlist_head *refs = &epi->ep->refs; if (hlist_empty(refs)) |
d16312a46 clean reverse_pat... |
1264 1265 |
error = path_count_inc(depth); else |
319c15174 epoll: take epite... |
1266 |
error = reverse_path_check_proc(refs, depth + 1); |
d16312a46 clean reverse_pat... |
1267 1268 |
if (error != 0) break; |
28d82dc1c epoll: limit paths |
1269 1270 1271 1272 1273 |
} return error; } /** |
319c15174 epoll: take epite... |
1274 |
* reverse_path_check - The tfile_check_list is list of epitem_head, which have |
28d82dc1c epoll: limit paths |
1275 1276 1277 1278 1279 |
* links that are proposed to be newly added. We need to * make sure that those added links don't add too many * paths such that we will spend all our time waking up * eventpoll objects. * |
a6c67fee9 fs: eventpoll: fi... |
1280 1281 |
* Return: %zero if the proposed links don't create too many paths, * %-1 otherwise. |
28d82dc1c epoll: limit paths |
1282 1283 1284 |
*/ static int reverse_path_check(void) { |
319c15174 epoll: take epite... |
1285 |
struct epitems_head *p; |
28d82dc1c epoll: limit paths |
1286 |
|
319c15174 epoll: take epite... |
1287 1288 |
for (p = tfile_check_list; p != EP_UNACTIVE_PTR; p = p->next) { int error; |
28d82dc1c epoll: limit paths |
1289 |
path_count_init(); |
b62d2706a lift rcu_read_loc... |
1290 |
rcu_read_lock(); |
319c15174 epoll: take epite... |
1291 |
error = reverse_path_check_proc(&p->epitems, 0); |
b62d2706a lift rcu_read_loc... |
1292 |
rcu_read_unlock(); |
28d82dc1c epoll: limit paths |
1293 |
if (error) |
319c15174 epoll: take epite... |
1294 |
return error; |
28d82dc1c epoll: limit paths |
1295 |
} |
319c15174 epoll: take epite... |
1296 |
return 0; |
28d82dc1c epoll: limit paths |
1297 |
} |
4d7e30d98 epoll: Add a flag... |
1298 1299 |
static int ep_create_wakeup_source(struct epitem *epi) { |
3701cb59d ep_create_wakeup_... |
1300 |
struct name_snapshot n; |
eea1d5859 epoll: use RCU to... |
1301 |
struct wakeup_source *ws; |
4d7e30d98 epoll: Add a flag... |
1302 1303 |
if (!epi->ep->ws) { |
c8377adfa PM / wakeup: Show... |
1304 |
epi->ep->ws = wakeup_source_register(NULL, "eventpoll"); |
4d7e30d98 epoll: Add a flag... |
1305 1306 1307 |
if (!epi->ep->ws) return -ENOMEM; } |
3701cb59d ep_create_wakeup_... |
1308 1309 1310 |
take_dentry_name_snapshot(&n, epi->ffd.file->f_path.dentry); ws = wakeup_source_register(NULL, n.name.name); release_dentry_name_snapshot(&n); |
eea1d5859 epoll: use RCU to... |
1311 1312 |
if (!ws) |
4d7e30d98 epoll: Add a flag... |
1313 |
return -ENOMEM; |
eea1d5859 epoll: use RCU to... |
1314 |
rcu_assign_pointer(epi->ws, ws); |
4d7e30d98 epoll: Add a flag... |
1315 1316 1317 |
return 0; } |
eea1d5859 epoll: use RCU to... |
1318 1319 |
/* rare code path, only used when EPOLL_CTL_MOD removes a wakeup source */ static noinline void ep_destroy_wakeup_source(struct epitem *epi) |
4d7e30d98 epoll: Add a flag... |
1320 |
{ |
eea1d5859 epoll: use RCU to... |
1321 |
struct wakeup_source *ws = ep_wakeup_source(epi); |
d6d67e723 epoll: cleanup: u... |
1322 |
RCU_INIT_POINTER(epi->ws, NULL); |
eea1d5859 epoll: use RCU to... |
1323 1324 1325 1326 1327 1328 1329 1330 |
/* * wait for ep_pm_stay_awake_rcu to finish, synchronize_rcu is * used internally by wakeup_source_remove, too (called by * wakeup_source_unregister), so we cannot use call_rcu */ synchronize_rcu(); wakeup_source_unregister(ws); |
4d7e30d98 epoll: Add a flag... |
1331 |
} |
319c15174 epoll: take epite... |
1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 |
static int attach_epitem(struct file *file, struct epitem *epi) { struct epitems_head *to_free = NULL; struct hlist_head *head = NULL; struct eventpoll *ep = NULL; if (is_file_epoll(file)) ep = file->private_data; if (ep) { head = &ep->refs; } else if (!READ_ONCE(file->f_ep)) { allocate: to_free = kmem_cache_zalloc(ephead_cache, GFP_KERNEL); if (!to_free) return -ENOMEM; head = &to_free->epitems; } spin_lock(&file->f_lock); if (!file->f_ep) { if (unlikely(!head)) { spin_unlock(&file->f_lock); goto allocate; } file->f_ep = head; to_free = NULL; } hlist_add_head_rcu(&epi->fllink, file->f_ep); spin_unlock(&file->f_lock); free_ephead(to_free); return 0; } |
c7ea76302 epoll locks chang... |
1364 1365 1366 |
/* * Must be called with "mtx" held. */ |
bec1a502d eventpoll: consti... |
1367 |
static int ep_insert(struct eventpoll *ep, const struct epoll_event *event, |
67347fe4e epoll: do not tak... |
1368 |
struct file *tfile, int fd, int full_check) |
1da177e4c Linux-2.6.12-rc2 |
1369 |
{ |
d85e2aa2e annotate ep_scan_... |
1370 1371 |
int error, pwake = 0; __poll_t revents; |
1da177e4c Linux-2.6.12-rc2 |
1372 1373 |
struct epitem *epi; struct ep_pqueue epq; |
85353e919 ep_insert(): we o... |
1374 1375 1376 1377 |
struct eventpoll *tep = NULL; if (is_file_epoll(tfile)) tep = tfile->private_data; |
1da177e4c Linux-2.6.12-rc2 |
1378 |
|
92e641784 s/epoll: robustif... |
1379 |
lockdep_assert_irqs_enabled(); |
1e1c15839 fs/epoll: use a p... |
1380 1381 |
if (unlikely(percpu_counter_compare(&ep->user->epoll_watches, max_user_watches) >= 0)) |
7ef9964e6 epoll: introduce ... |
1382 |
return -ENOSPC; |
1e1c15839 fs/epoll: use a p... |
1383 1384 1385 1386 |
percpu_counter_inc(&ep->user->epoll_watches); if (!(epi = kmem_cache_zalloc(epi_cache, GFP_KERNEL))) { percpu_counter_dec(&ep->user->epoll_watches); |
7ef9964e6 epoll: introduce ... |
1387 |
return -ENOMEM; |
1e1c15839 fs/epoll: use a p... |
1388 |
} |
1da177e4c Linux-2.6.12-rc2 |
1389 1390 |
/* Item initialization follow here ... */ |
1da177e4c Linux-2.6.12-rc2 |
1391 |
INIT_LIST_HEAD(&epi->rdllink); |
1da177e4c Linux-2.6.12-rc2 |
1392 |
epi->ep = ep; |
b030a4dd6 [PATCH] Remove ev... |
1393 |
ep_set_ffd(&epi->ffd, tfile, fd); |
1da177e4c Linux-2.6.12-rc2 |
1394 |
epi->event = *event; |
d47de16c7 fix epoll single ... |
1395 |
epi->next = EP_UNACTIVE_PTR; |
1da177e4c Linux-2.6.12-rc2 |
1396 |
|
85353e919 ep_insert(): we o... |
1397 1398 |
if (tep) mutex_lock_nested(&tep->mtx, 1); |
f8d4f44df epoll: do not ins... |
1399 |
/* Add the current item to the list of active epoll hook for this file */ |
319c15174 epoll: take epite... |
1400 |
if (unlikely(attach_epitem(tfile, epi) < 0)) { |
319c15174 epoll: take epite... |
1401 1402 |
if (tep) mutex_unlock(&tep->mtx); |
1e1c15839 fs/epoll: use a p... |
1403 1404 |
kmem_cache_free(epi_cache, epi); percpu_counter_dec(&ep->user->epoll_watches); |
319c15174 epoll: take epite... |
1405 |
return -ENOMEM; |
d9f41e3c9 epoll: massage th... |
1406 |
} |
f8d4f44df epoll: do not ins... |
1407 |
|
319c15174 epoll: take epite... |
1408 1409 |
if (full_check && !tep) list_file(tfile); |
f8d4f44df epoll: do not ins... |
1410 1411 1412 1413 1414 |
/* * Add the current item to the RB tree. All RB tree operations are * protected by "mtx", and ep_insert() is called with "mtx" held. */ ep_rbtree_insert(ep, epi); |
85353e919 ep_insert(): we o... |
1415 1416 |
if (tep) mutex_unlock(&tep->mtx); |
f8d4f44df epoll: do not ins... |
1417 1418 |
/* now check if we've created too many backpaths */ |
e3e096e7f ep_insert(): don'... |
1419 1420 1421 1422 |
if (unlikely(full_check && reverse_path_check())) { ep_remove(ep, epi); return -EINVAL; } |
f8d4f44df epoll: do not ins... |
1423 |
|
d1ec50adb ep_insert(): move... |
1424 1425 1426 1427 1428 1429 1430 |
if (epi->event.events & EPOLLWAKEUP) { error = ep_create_wakeup_source(epi); if (error) { ep_remove(ep, epi); return error; } } |
f8d4f44df epoll: do not ins... |
1431 |
|
1da177e4c Linux-2.6.12-rc2 |
1432 1433 1434 1435 1436 1437 1438 |
/* Initialize the poll table using the queue callback */ epq.epi = epi; init_poll_funcptr(&epq.pt, ep_ptable_queue_proc); /* * Attach the item to the poll hooks and get current event bits. * We can safely use the file* here because its usage count has |
c7ea76302 epoll locks chang... |
1439 1440 1441 |
* been increased by the caller of this function. Note that after * this operation completes, the poll callback can start hitting * the new item. |
1da177e4c Linux-2.6.12-rc2 |
1442 |
*/ |
37b5e5212 epoll: remove ep_... |
1443 |
revents = ep_item_poll(epi, &epq.pt, 1); |
1da177e4c Linux-2.6.12-rc2 |
1444 1445 1446 1447 1448 1449 |
/* * We have to check if something went wrong during the poll wait queue * install process. Namely an allocation for a wait queue failed due * high memory pressure. */ |
e3e096e7f ep_insert(): don'... |
1450 1451 1452 1453 |
if (unlikely(!epq.epi)) { ep_remove(ep, epi); return -ENOMEM; } |
1da177e4c Linux-2.6.12-rc2 |
1454 |
|
c7ea76302 epoll locks chang... |
1455 |
/* We have to drop the new item inside our item list to keep track of it */ |
a218cc491 epoll: use rwlock... |
1456 |
write_lock_irq(&ep->lock); |
c7ea76302 epoll locks chang... |
1457 |
|
bf3b9f637 epoll: Add busy p... |
1458 1459 |
/* record NAPI ID of new item if present */ ep_set_busy_poll_napi_id(epi); |
1da177e4c Linux-2.6.12-rc2 |
1460 |
/* If the file is already "ready" we drop it inside the ready list */ |
992991c03 fs/eventpoll.c: s... |
1461 |
if (revents && !ep_is_linked(epi)) { |
1da177e4c Linux-2.6.12-rc2 |
1462 |
list_add_tail(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
1463 |
ep_pm_stay_awake(epi); |
1da177e4c Linux-2.6.12-rc2 |
1464 1465 1466 |
/* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) |
a218cc491 epoll: use rwlock... |
1467 |
wake_up(&ep->wq); |
1da177e4c Linux-2.6.12-rc2 |
1468 1469 1470 |
if (waitqueue_active(&ep->poll_wait)) pwake++; } |
a218cc491 epoll: use rwlock... |
1471 |
write_unlock_irq(&ep->lock); |
1da177e4c Linux-2.6.12-rc2 |
1472 1473 1474 |
/* We have to call this outside the lock */ if (pwake) |
efcdd350d fs/epoll: make ne... |
1475 |
ep_poll_safewake(ep, NULL); |
1da177e4c Linux-2.6.12-rc2 |
1476 |
|
1da177e4c Linux-2.6.12-rc2 |
1477 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
1478 |
} |
1da177e4c Linux-2.6.12-rc2 |
1479 1480 |
/* * Modify the interest event mask by dropping an event if the new mask |
c7ea76302 epoll locks chang... |
1481 |
* has a match in the current file status. Must be called with "mtx" held. |
1da177e4c Linux-2.6.12-rc2 |
1482 |
*/ |
bec1a502d eventpoll: consti... |
1483 1484 |
static int ep_modify(struct eventpoll *ep, struct epitem *epi, const struct epoll_event *event) |
1da177e4c Linux-2.6.12-rc2 |
1485 1486 |
{ int pwake = 0; |
626cf2366 poll: add poll_re... |
1487 |
poll_table pt; |
92e641784 s/epoll: robustif... |
1488 |
lockdep_assert_irqs_enabled(); |
626cf2366 poll: add poll_re... |
1489 |
init_poll_funcptr(&pt, NULL); |
1da177e4c Linux-2.6.12-rc2 |
1490 1491 |
/* |
e057e15ff epoll: clean up e... |
1492 1493 1494 |
* Set the new event interest mask before calling f_op->poll(); * otherwise we might miss an event that happens between the * f_op->poll() call and the new event set registering. |
1da177e4c Linux-2.6.12-rc2 |
1495 |
*/ |
128dd1759 epoll: prevent mi... |
1496 |
epi->event.events = event->events; /* need barrier below */ |
e057e15ff epoll: clean up e... |
1497 |
epi->event.data = event->data; /* protected by mtx */ |
4d7e30d98 epoll: Add a flag... |
1498 |
if (epi->event.events & EPOLLWAKEUP) { |
eea1d5859 epoll: use RCU to... |
1499 |
if (!ep_has_wakeup_source(epi)) |
4d7e30d98 epoll: Add a flag... |
1500 |
ep_create_wakeup_source(epi); |
eea1d5859 epoll: use RCU to... |
1501 |
} else if (ep_has_wakeup_source(epi)) { |
4d7e30d98 epoll: Add a flag... |
1502 1503 |
ep_destroy_wakeup_source(epi); } |
1da177e4c Linux-2.6.12-rc2 |
1504 1505 |
/* |
128dd1759 epoll: prevent mi... |
1506 1507 1508 1509 1510 |
* The following barrier has two effects: * * 1) Flush epi changes above to other CPUs. This ensures * we do not miss events from ep_poll_callback if an * event occurs immediately after we call f_op->poll(). |
a218cc491 epoll: use rwlock... |
1511 |
* We need this because we did not take ep->lock while |
128dd1759 epoll: prevent mi... |
1512 |
* changing epi above (but ep_poll_callback does take |
a218cc491 epoll: use rwlock... |
1513 |
* ep->lock). |
128dd1759 epoll: prevent mi... |
1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 |
* * 2) We also need to ensure we do not miss _past_ events * when calling f_op->poll(). This barrier also * pairs with the barrier in wq_has_sleeper (see * comments for wq_has_sleeper). * * This barrier will now guarantee ep_poll_callback or f_op->poll * (or both) will notice the readiness of an item. */ smp_mb(); /* |
1da177e4c Linux-2.6.12-rc2 |
1526 1527 |
* Get current event bits. We can safely use the file* here because * its usage count has been increased by the caller of this function. |
c7ea76302 epoll locks chang... |
1528 |
* If the item is "hot" and it is not registered inside the ready |
67647d0fb epoll: fix some c... |
1529 |
* list, push it inside. |
1da177e4c Linux-2.6.12-rc2 |
1530 |
*/ |
69112736e eventpoll: no nee... |
1531 |
if (ep_item_poll(epi, &pt, 1)) { |
a218cc491 epoll: use rwlock... |
1532 |
write_lock_irq(&ep->lock); |
992991c03 fs/eventpoll.c: s... |
1533 |
if (!ep_is_linked(epi)) { |
c7ea76302 epoll locks chang... |
1534 |
list_add_tail(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
1535 |
ep_pm_stay_awake(epi); |
c7ea76302 epoll locks chang... |
1536 1537 1538 |
/* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) |
a218cc491 epoll: use rwlock... |
1539 |
wake_up(&ep->wq); |
c7ea76302 epoll locks chang... |
1540 1541 |
if (waitqueue_active(&ep->poll_wait)) pwake++; |
7699acd13 epoll cleanups: e... |
1542 |
} |
a218cc491 epoll: use rwlock... |
1543 |
write_unlock_irq(&ep->lock); |
7699acd13 epoll cleanups: e... |
1544 |
} |
1da177e4c Linux-2.6.12-rc2 |
1545 |
|
7699acd13 epoll cleanups: e... |
1546 1547 |
/* We have to call this outside the lock */ if (pwake) |
efcdd350d fs/epoll: make ne... |
1548 |
ep_poll_safewake(ep, NULL); |
1da177e4c Linux-2.6.12-rc2 |
1549 |
|
7699acd13 epoll cleanups: e... |
1550 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
1551 |
} |
ff07952ae ep_send_events_pr... |
1552 1553 |
static int ep_send_events(struct eventpoll *ep, struct epoll_event __user *events, int maxevents) |
1da177e4c Linux-2.6.12-rc2 |
1554 |
{ |
4e0982a00 fs/epoll: simplif... |
1555 |
struct epitem *epi, *tmp; |
ff07952ae ep_send_events_pr... |
1556 |
LIST_HEAD(txlist); |
626cf2366 poll: add poll_re... |
1557 |
poll_table pt; |
ff07952ae ep_send_events_pr... |
1558 |
int res = 0; |
626cf2366 poll: add poll_re... |
1559 |
|
cccd29bf0 epoll: pull fatal... |
1560 1561 1562 1563 1564 1565 1566 |
/* * Always short-circuit for fatal signals to allow threads to make a * timely exit without the chance of finding more events available and * fetching repeatedly. */ if (fatal_signal_pending(current)) return -EINTR; |
626cf2366 poll: add poll_re... |
1567 |
init_poll_funcptr(&pt, NULL); |
ff07952ae ep_send_events_pr... |
1568 |
|
57804b1cc lift locking/unlo... |
1569 1570 |
mutex_lock(&ep->mtx); ep_start_scan(ep, &txlist); |
1da177e4c Linux-2.6.12-rc2 |
1571 |
|
296e236e9 epoll: fix epoll'... |
1572 |
/* |
5071f97ec epoll: fix epoll'... |
1573 |
* We can loop without lock because we are passed a task private list. |
57804b1cc lift locking/unlo... |
1574 |
* Items cannot vanish during the loop we are holding ep->mtx. |
296e236e9 epoll: fix epoll'... |
1575 |
*/ |
ff07952ae ep_send_events_pr... |
1576 1577 1578 |
list_for_each_entry_safe(epi, tmp, &txlist, rdllink) { struct wakeup_source *ws; __poll_t revents; |
21877e1a5 fs/epoll: robusti... |
1579 |
|
ff07952ae ep_send_events_pr... |
1580 |
if (res >= maxevents) |
4e0982a00 fs/epoll: simplif... |
1581 |
break; |
d47de16c7 fix epoll single ... |
1582 |
|
4d7e30d98 epoll: Add a flag... |
1583 1584 1585 1586 1587 1588 1589 1590 1591 |
/* * Activate ep->ws before deactivating epi->ws to prevent * triggering auto-suspend here (in case we reactive epi->ws * below). * * This could be rearranged to delay the deactivation of epi->ws * instead, but then epi->ws would temporarily be out of sync * with ep_is_linked(). */ |
eea1d5859 epoll: use RCU to... |
1592 1593 1594 1595 1596 1597 |
ws = ep_wakeup_source(epi); if (ws) { if (ws->active) __pm_stay_awake(ep->ws); __pm_relax(ws); } |
d47de16c7 fix epoll single ... |
1598 |
list_del_init(&epi->rdllink); |
1da177e4c Linux-2.6.12-rc2 |
1599 |
|
296e236e9 epoll: fix epoll'... |
1600 |
/* |
5071f97ec epoll: fix epoll'... |
1601 |
* If the event mask intersect the caller-requested one, |
57804b1cc lift locking/unlo... |
1602 1603 |
* deliver the event to userspace. Again, we are holding ep->mtx, * so no operations coming from userspace can change the item. |
296e236e9 epoll: fix epoll'... |
1604 |
*/ |
4e0982a00 fs/epoll: simplif... |
1605 1606 1607 |
revents = ep_item_poll(epi, &pt, 1); if (!revents) continue; |
249dbe74d ARM: 9108/1: oabi... |
1608 1609 |
events = epoll_put_uevent(revents, epi->event.data, events); if (!events) { |
ff07952ae ep_send_events_pr... |
1610 |
list_add(&epi->rdllink, &txlist); |
4e0982a00 fs/epoll: simplif... |
1611 |
ep_pm_stay_awake(epi); |
ff07952ae ep_send_events_pr... |
1612 1613 1614 |
if (!res) res = -EFAULT; break; |
4e0982a00 fs/epoll: simplif... |
1615 |
} |
ff07952ae ep_send_events_pr... |
1616 |
res++; |
4e0982a00 fs/epoll: simplif... |
1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 |
if (epi->event.events & EPOLLONESHOT) epi->event.events &= EP_PRIVATE_BITS; else if (!(epi->event.events & EPOLLET)) { /* * If this file has been added with Level * Trigger mode, we need to insert back inside * the ready list, so that the next call to * epoll_wait() will check again the events * availability. At this point, no one can insert * into ep->rdllist besides us. The epoll_ctl() * callers are locked out by * ep_scan_ready_list() holding "mtx" and the * poll callback will queue them in ep->ovflist. */ list_add_tail(&epi->rdllink, &ep->rdllist); ep_pm_stay_awake(epi); |
296e236e9 epoll: fix epoll'... |
1633 1634 |
} } |
57804b1cc lift locking/unlo... |
1635 1636 |
ep_done_scan(ep, &txlist); mutex_unlock(&ep->mtx); |
5071f97ec epoll: fix epoll'... |
1637 |
|
ff07952ae ep_send_events_pr... |
1638 |
return res; |
1da177e4c Linux-2.6.12-rc2 |
1639 |
} |
7cdf7c20e epoll: convert in... |
1640 |
static struct timespec64 *ep_timeout_to_timespec(struct timespec64 *to, long ms) |
0781b909b epoll: epoll_wait... |
1641 |
{ |
7cdf7c20e epoll: convert in... |
1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 |
struct timespec64 now; if (ms < 0) return NULL; if (!ms) { to->tv_sec = 0; to->tv_nsec = 0; return to; } to->tv_sec = ms / MSEC_PER_SEC; to->tv_nsec = NSEC_PER_MSEC * (ms % MSEC_PER_SEC); |
0781b909b epoll: epoll_wait... |
1655 |
|
766b9f928 fs: poll/select/r... |
1656 |
ktime_get_ts64(&now); |
7cdf7c20e epoll: convert in... |
1657 1658 |
*to = timespec64_add_safe(now, *to); return to; |
0781b909b epoll: epoll_wait... |
1659 |
} |
9ccb5d391 epoll: autoremove... |
1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 |
/* * autoremove_wake_function, but remove even on failure to wake up, because we * know that default_wake_function/ttwu will only fail if the thread is already * woken, and in that case the ep_poll loop will remove the entry anyways, not * try to reuse it. */ static int ep_autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned int mode, int sync, void *key) { int ret = default_wake_function(wq_entry, mode, sync, key); list_del_init(&wq_entry->entry); return ret; } |
f4d93ad74 epoll: fix compil... |
1674 |
/** |
a6c67fee9 fs: eventpoll: fi... |
1675 |
* ep_poll - Retrieves ready events, and delivers them to the caller-supplied |
f4d93ad74 epoll: fix compil... |
1676 1677 1678 1679 1680 1681 1682 |
* event buffer. * * @ep: Pointer to the eventpoll context. * @events: Pointer to the userspace buffer where the ready events should be * stored. * @maxevents: Size (in terms of number of events) of the caller event buffer. * @timeout: Maximum timeout for the ready events fetch operation, in |
7cdf7c20e epoll: convert in... |
1683 1684 |
* timespec. If the timeout is zero, the function will not block, * while if the @timeout ptr is NULL, the function will block |
f4d93ad74 epoll: fix compil... |
1685 1686 1687 |
* until at least one event has been retrieved (or an error * occurred). * |
a6c67fee9 fs: eventpoll: fi... |
1688 |
* Return: the number of ready events which have been fetched, or an |
f4d93ad74 epoll: fix compil... |
1689 1690 |
* error code, in case of error. */ |
1da177e4c Linux-2.6.12-rc2 |
1691 |
static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events, |
7cdf7c20e epoll: convert in... |
1692 |
int maxevents, struct timespec64 *timeout) |
1da177e4c Linux-2.6.12-rc2 |
1693 |
{ |
e59d3c64c epoll: eliminate ... |
1694 |
int res, eavail, timed_out = 0; |
da8b44d5a timer: convert ti... |
1695 |
u64 slack = 0; |
ac6424b98 sched/wait: Renam... |
1696 |
wait_queue_entry_t wait; |
95aac7b1c epoll: make epoll... |
1697 |
ktime_t expires, *to = NULL; |
679abf381 fs/eventpoll.c: l... |
1698 |
lockdep_assert_irqs_enabled(); |
7cdf7c20e epoll: convert in... |
1699 1700 |
if (timeout && (timeout->tv_sec | timeout->tv_nsec)) { slack = select_estimate_accuracy(timeout); |
95aac7b1c epoll: make epoll... |
1701 |
to = &expires; |
7cdf7c20e epoll: convert in... |
1702 1703 |
*to = timespec64_to_ktime(*timeout); } else if (timeout) { |
f4d93ad74 epoll: fix compil... |
1704 1705 |
/* * Avoid the unnecessary trip to the wait queue loop, if the |
e59d3c64c epoll: eliminate ... |
1706 |
* caller specified a non blocking operation. |
f4d93ad74 epoll: fix compil... |
1707 |
*/ |
95aac7b1c epoll: make epoll... |
1708 1709 |
timed_out = 1; } |
1da177e4c Linux-2.6.12-rc2 |
1710 |
|
e59d3c64c epoll: eliminate ... |
1711 1712 |
/* * This call is racy: We may or may not see events that are being added |
a6c67fee9 fs: eventpoll: fi... |
1713 |
* to the ready list under the lock (e.g., in IRQ callbacks). For cases |
e59d3c64c epoll: eliminate ... |
1714 |
* with a non-zero timeout, this thread will check the ready list under |
a6c67fee9 fs: eventpoll: fi... |
1715 |
* lock and will add to the wait queue. For cases with a zero |
e59d3c64c epoll: eliminate ... |
1716 1717 1718 1719 |
* timeout, the user by definition should not care and will have to * recheck again. */ eavail = ep_events_available(ep); |
00b27634b epoll: replace go... |
1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 |
while (1) { if (eavail) { /* * Try to transfer events to user space. In case we get * 0 events and there's still timeout left over, we go * trying again in search of more luck. */ res = ep_send_events(ep, events, maxevents); if (res) return res; } if (timed_out) return 0; |
00b27634b epoll: replace go... |
1734 |
eavail = ep_busy_loop(ep, timed_out); |
e8c85328b epoll: pull all c... |
1735 |
if (eavail) |
00b27634b epoll: replace go... |
1736 |
continue; |
1da177e4c Linux-2.6.12-rc2 |
1737 |
|
2efdaf766 epoll: simplify s... |
1738 1739 |
if (signal_pending(current)) return -EINTR; |
412895f03 epoll: atomically... |
1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 |
/* * Internally init_wait() uses autoremove_wake_function(), * thus wait entry is removed from the wait queue on each * wakeup. Why it is important? In case of several waiters * each new wakeup will hit the next waiter, giving it the * chance to harvest new event. Otherwise wakeup can be * lost. This is also good performance-wise, because on * normal wakeup path no need to call __remove_wait_queue() * explicitly, thus ep->lock is not taken, which halts the * event delivery. |
9ccb5d391 epoll: autoremove... |
1750 1751 1752 1753 1754 1755 |
* * In fact, we now use an even more aggressive function that * unconditionally removes, because we don't reuse the wait * entry between loop iterations. This lets us also avoid the * performance issue if a process is killed, causing all of its * threads to wake up without being removed normally. |
412895f03 epoll: atomically... |
1756 1757 |
*/ init_wait(&wait); |
9ccb5d391 epoll: autoremove... |
1758 |
wait.func = ep_autoremove_wake_function; |
1da177e4c Linux-2.6.12-rc2 |
1759 |
|
65759097d epoll: call final... |
1760 |
write_lock_irq(&ep->lock); |
1da177e4c Linux-2.6.12-rc2 |
1761 |
/* |
65759097d epoll: call final... |
1762 1763 1764 |
* Barrierless variant, waitqueue_active() is called under * the same lock on wakeup ep_poll_callback() side, so it * is safe to avoid an explicit barrier. |
bf3b9f637 epoll: Add busy p... |
1765 |
*/ |
65759097d epoll: call final... |
1766 |
__set_current_state(TASK_INTERRUPTIBLE); |
bf3b9f637 epoll: Add busy p... |
1767 |
/* |
65759097d epoll: call final... |
1768 1769 1770 1771 1772 |
* Do the final check under the lock. ep_scan_ready_list() * plays with two lists (->rdllist and ->ovflist) and there * is always a race when both lists are empty for short * period of time although events are pending, so lock is * important. |
1da177e4c Linux-2.6.12-rc2 |
1773 |
*/ |
65759097d epoll: call final... |
1774 |
eavail = ep_events_available(ep); |
2efdaf766 epoll: simplify s... |
1775 1776 |
if (!eavail) __add_wait_queue_exclusive(&ep->wq, &wait); |
65759097d epoll: call final... |
1777 |
write_unlock_irq(&ep->lock); |
95aac7b1c epoll: make epoll... |
1778 |
|
2efdaf766 epoll: simplify s... |
1779 |
if (!eavail) |
289caf5d8 epoll: check for ... |
1780 1781 |
timed_out = !schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS); |
e411596d4 epoll: move eavai... |
1782 |
__set_current_state(TASK_RUNNING); |
1da177e4c Linux-2.6.12-rc2 |
1783 |
|
289caf5d8 epoll: check for ... |
1784 1785 1786 1787 1788 |
/* * We were woken up, thus go and try to harvest some events. * If timed out and still on the wait queue, recheck eavail * carefully under lock, below. */ |
412895f03 epoll: atomically... |
1789 |
eavail = 1; |
1da177e4c Linux-2.6.12-rc2 |
1790 |
|
e8c85328b epoll: pull all c... |
1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 |
if (!list_empty_careful(&wait.entry)) { write_lock_irq(&ep->lock); /* * If the thread timed out and is not on the wait queue, * it means that the thread was woken up after its * timeout expired before it could reacquire the lock. * Thus, when wait.entry is empty, it needs to harvest * events. */ if (timed_out) eavail = list_empty(&wait.entry); __remove_wait_queue(&ep->wq, &wait); write_unlock_irq(&ep->lock); } |
00b27634b epoll: replace go... |
1805 |
} |
1da177e4c Linux-2.6.12-rc2 |
1806 |
} |
22bacca48 epoll: prevent cr... |
1807 |
/** |
773318edd untangling ep_cal... |
1808 |
* ep_loop_check_proc - verify that adding an epoll file inside another |
a6c67fee9 fs: eventpoll: fi... |
1809 |
* epoll structure does not violate the constraints, in |
22bacca48 epoll: prevent cr... |
1810 1811 1812 |
* terms of closed loops, or too deep chains (which can * result in excessive stack usage). * |
a6c67fee9 fs: eventpoll: fi... |
1813 |
* @ep: the &struct eventpoll to be currently checked. |
bde03c4c1 ep_loop_check_pro... |
1814 |
* @depth: Current depth of the path being checked. |
22bacca48 epoll: prevent cr... |
1815 |
* |
a6c67fee9 fs: eventpoll: fi... |
1816 1817 |
* Return: %zero if adding the epoll @file inside current epoll * structure @ep does not violate the constraints, or %-1 otherwise. |
22bacca48 epoll: prevent cr... |
1818 |
*/ |
bde03c4c1 ep_loop_check_pro... |
1819 |
static int ep_loop_check_proc(struct eventpoll *ep, int depth) |
22bacca48 epoll: prevent cr... |
1820 1821 |
{ int error = 0; |
22bacca48 epoll: prevent cr... |
1822 1823 |
struct rb_node *rbp; struct epitem *epi; |
773318edd untangling ep_cal... |
1824 |
mutex_lock_nested(&ep->mtx, depth + 1); |
18306c404 epoll: replace ->... |
1825 |
ep->gen = loop_check_gen; |
b2ac2ea62 fs/epoll: use fas... |
1826 |
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
22bacca48 epoll: prevent cr... |
1827 1828 |
epi = rb_entry(rbp, struct epitem, rbn); if (unlikely(is_file_epoll(epi->ffd.file))) { |
bde03c4c1 ep_loop_check_pro... |
1829 |
struct eventpoll *ep_tovisit; |
28d82dc1c epoll: limit paths |
1830 |
ep_tovisit = epi->ffd.file->private_data; |
18306c404 epoll: replace ->... |
1831 |
if (ep_tovisit->gen == loop_check_gen) |
28d82dc1c epoll: limit paths |
1832 |
continue; |
bde03c4c1 ep_loop_check_pro... |
1833 |
if (ep_tovisit == inserting_into || depth > EP_MAX_NESTS) |
56c428cac ep_loop_check_pro... |
1834 |
error = -1; |
bde03c4c1 ep_loop_check_pro... |
1835 1836 |
else error = ep_loop_check_proc(ep_tovisit, depth + 1); |
22bacca48 epoll: prevent cr... |
1837 1838 |
if (error != 0) break; |
28d82dc1c epoll: limit paths |
1839 1840 1841 1842 1843 1844 1845 1846 1847 |
} else { /* * If we've reached a file that is not associated with * an ep, then we need to check if the newly added * links are going to add too many wakeup paths. We do * this by adding it to the tfile_check_list, if it's * not already there, and calling reverse_path_check() * during ep_insert(). */ |
319c15174 epoll: take epite... |
1848 |
list_file(epi->ffd.file); |
22bacca48 epoll: prevent cr... |
1849 1850 1851 1852 1853 1854 1855 1856 |
} } mutex_unlock(&ep->mtx); return error; } /** |
bde03c4c1 ep_loop_check_pro... |
1857 |
* ep_loop_check - Performs a check to verify that adding an epoll file (@to) |
a6c67fee9 fs: eventpoll: fi... |
1858 |
* into another epoll file (represented by @ep) does not create |
22bacca48 epoll: prevent cr... |
1859 1860 |
* closed loops or too deep chains. * |
a6c67fee9 fs: eventpoll: fi... |
1861 |
* @ep: Pointer to the epoll we are inserting into. |
bde03c4c1 ep_loop_check_pro... |
1862 |
* @to: Pointer to the epoll to be inserted. |
22bacca48 epoll: prevent cr... |
1863 |
* |
a6c67fee9 fs: eventpoll: fi... |
1864 1865 |
* Return: %zero if adding the epoll @to inside the epoll @from * does not violate the constraints, or %-1 otherwise. |
22bacca48 epoll: prevent cr... |
1866 |
*/ |
bde03c4c1 ep_loop_check_pro... |
1867 |
static int ep_loop_check(struct eventpoll *ep, struct eventpoll *to) |
22bacca48 epoll: prevent cr... |
1868 |
{ |
6a3890c47 get rid of ep_pus... |
1869 |
inserting_into = ep; |
bde03c4c1 ep_loop_check_pro... |
1870 |
return ep_loop_check_proc(to, 0); |
28d82dc1c epoll: limit paths |
1871 1872 1873 1874 |
} static void clear_tfile_check_list(void) { |
319c15174 epoll: take epite... |
1875 1876 1877 1878 1879 |
rcu_read_lock(); while (tfile_check_list != EP_UNACTIVE_PTR) { struct epitems_head *head = tfile_check_list; tfile_check_list = head->next; unlist_file(head); |
28d82dc1c epoll: limit paths |
1880 |
} |
319c15174 epoll: take epite... |
1881 |
rcu_read_unlock(); |
22bacca48 epoll: prevent cr... |
1882 |
} |
7699acd13 epoll cleanups: e... |
1883 |
/* |
523723bb5 fs/eventpoll.c: f... |
1884 |
* Open an eventpoll file descriptor. |
7699acd13 epoll cleanups: e... |
1885 |
*/ |
791eb22ee fs: add do_epoll_... |
1886 |
static int do_epoll_create(int flags) |
7699acd13 epoll cleanups: e... |
1887 |
{ |
28d82dc1c epoll: limit paths |
1888 |
int error, fd; |
bb57c3edc epoll: remove deb... |
1889 |
struct eventpoll *ep = NULL; |
28d82dc1c epoll: limit paths |
1890 |
struct file *file; |
7699acd13 epoll cleanups: e... |
1891 |
|
e38b36f32 flag parameters: ... |
1892 1893 |
/* Check the EPOLL_* constant for consistency. */ BUILD_BUG_ON(EPOLL_CLOEXEC != O_CLOEXEC); |
296e236e9 epoll: fix epoll'... |
1894 1895 |
if (flags & ~EPOLL_CLOEXEC) return -EINVAL; |
7699acd13 epoll cleanups: e... |
1896 |
/* |
bb57c3edc epoll: remove deb... |
1897 |
* Create the internal data structure ("struct eventpoll"). |
7699acd13 epoll cleanups: e... |
1898 |
*/ |
9fe5ad9c8 flag parameters a... |
1899 |
error = ep_alloc(&ep); |
bb57c3edc epoll: remove deb... |
1900 1901 |
if (error < 0) return error; |
7699acd13 epoll cleanups: e... |
1902 1903 |
/* * Creates all the items needed to setup an eventpoll file. That is, |
2030a42ce [PATCH] sanitize ... |
1904 |
* a file structure and a free file descriptor. |
7699acd13 epoll cleanups: e... |
1905 |
*/ |
28d82dc1c epoll: limit paths |
1906 1907 1908 1909 1910 1911 |
fd = get_unused_fd_flags(O_RDWR | (flags & O_CLOEXEC)); if (fd < 0) { error = fd; goto out_free_ep; } file = anon_inode_getfile("[eventpoll]", &eventpoll_fops, ep, |
628ff7c1d anonfd: Allow mak... |
1912 |
O_RDWR | (flags & O_CLOEXEC)); |
28d82dc1c epoll: limit paths |
1913 1914 1915 1916 |
if (IS_ERR(file)) { error = PTR_ERR(file); goto out_free_fd; } |
28d82dc1c epoll: limit paths |
1917 |
ep->file = file; |
98022748f eventpoll: use-af... |
1918 |
fd_install(fd, file); |
28d82dc1c epoll: limit paths |
1919 1920 1921 1922 1923 1924 |
return fd; out_free_fd: put_unused_fd(fd); out_free_ep: ep_free(ep); |
bb57c3edc epoll: remove deb... |
1925 |
return error; |
7699acd13 epoll cleanups: e... |
1926 |
} |
791eb22ee fs: add do_epoll_... |
1927 1928 1929 1930 |
SYSCALL_DEFINE1(epoll_create1, int, flags) { return do_epoll_create(flags); } |
5a8a82b1d [CVE-2009-0029] S... |
1931 |
SYSCALL_DEFINE1(epoll_create, int, size) |
a0998b50c flag parameters: ... |
1932 |
{ |
bfe3891a5 epoll: fix size c... |
1933 |
if (size <= 0) |
9fe5ad9c8 flag parameters a... |
1934 |
return -EINVAL; |
791eb22ee fs: add do_epoll_... |
1935 |
return do_epoll_create(0); |
a0998b50c flag parameters: ... |
1936 |
} |
39220e8d4 eventpoll: suppor... |
1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 |
static inline int epoll_mutex_lock(struct mutex *mutex, int depth, bool nonblock) { if (!nonblock) { mutex_lock_nested(mutex, depth); return 0; } if (mutex_trylock(mutex)) return 0; return -EAGAIN; } int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds, bool nonblock) |
7699acd13 epoll cleanups: e... |
1951 1952 |
{ int error; |
67347fe4e epoll: do not tak... |
1953 |
int full_check = 0; |
7e3fb5842 switch epoll_ctl(... |
1954 |
struct fd f, tf; |
7699acd13 epoll cleanups: e... |
1955 1956 |
struct eventpoll *ep; struct epitem *epi; |
67347fe4e epoll: do not tak... |
1957 |
struct eventpoll *tep = NULL; |
7699acd13 epoll cleanups: e... |
1958 |
|
7699acd13 epoll cleanups: e... |
1959 |
error = -EBADF; |
7e3fb5842 switch epoll_ctl(... |
1960 1961 |
f = fdget(epfd); if (!f.file) |
7699acd13 epoll cleanups: e... |
1962 1963 1964 |
goto error_return; /* Get the "struct file *" for the target file */ |
7e3fb5842 switch epoll_ctl(... |
1965 1966 |
tf = fdget(fd); if (!tf.file) |
7699acd13 epoll cleanups: e... |
1967 1968 1969 1970 |
goto error_fput; /* The target file descriptor must support poll */ error = -EPERM; |
9965ed174 fs: add new vfs_p... |
1971 |
if (!file_can_poll(tf.file)) |
7699acd13 epoll cleanups: e... |
1972 |
goto error_tgt_fput; |
4d7e30d98 epoll: Add a flag... |
1973 |
/* Check if EPOLLWAKEUP is allowed */ |
c680e41b3 eventpoll: fix un... |
1974 |
if (ep_op_has_event(op)) |
58e41a44c eventpoll: abstra... |
1975 |
ep_take_care_of_epollwakeup(epds); |
4d7e30d98 epoll: Add a flag... |
1976 |
|
7699acd13 epoll cleanups: e... |
1977 1978 1979 1980 1981 1982 |
/* * We have to check that the file structure underneath the file descriptor * the user passed to us _is_ an eventpoll file. And also we do not permit * adding an epoll file descriptor inside itself. */ error = -EINVAL; |
7e3fb5842 switch epoll_ctl(... |
1983 |
if (f.file == tf.file || !is_file_epoll(f.file)) |
7699acd13 epoll cleanups: e... |
1984 1985 1986 |
goto error_tgt_fput; /* |
df0108c5d epoll: add EPOLLE... |
1987 1988 1989 1990 |
* epoll adds to the wakeup queue at EPOLL_CTL_ADD time only, * so EPOLLEXCLUSIVE is not allowed for a EPOLL_CTL_MOD operation. * Also, we do not currently supported nested exclusive wakeups. */ |
58e41a44c eventpoll: abstra... |
1991 |
if (ep_op_has_event(op) && (epds->events & EPOLLEXCLUSIVE)) { |
b6a515c8a epoll: restrict E... |
1992 1993 1994 |
if (op == EPOLL_CTL_MOD) goto error_tgt_fput; if (op == EPOLL_CTL_ADD && (is_file_epoll(tf.file) || |
58e41a44c eventpoll: abstra... |
1995 |
(epds->events & ~EPOLLEXCLUSIVE_OK_BITS))) |
b6a515c8a epoll: restrict E... |
1996 1997 |
goto error_tgt_fput; } |
df0108c5d epoll: add EPOLLE... |
1998 1999 |
/* |
7699acd13 epoll cleanups: e... |
2000 2001 2002 |
* At this point it is safe to assume that the "private_data" contains * our own data structure. */ |
7e3fb5842 switch epoll_ctl(... |
2003 |
ep = f.file->private_data; |
7699acd13 epoll cleanups: e... |
2004 |
|
22bacca48 epoll: prevent cr... |
2005 |
/* |
a6c67fee9 fs: eventpoll: fi... |
2006 2007 |
* When we insert an epoll file descriptor inside another epoll file * descriptor, there is the chance of creating closed loops, which are |
28d82dc1c epoll: limit paths |
2008 2009 2010 2011 |
* better be handled here, than in more critical paths. While we are * checking for loops we also determine the list of files reachable * and hang them on the tfile_check_list, so we can check that we * haven't created too many possible wakeup paths. |
22bacca48 epoll: prevent cr... |
2012 |
* |
67347fe4e epoll: do not tak... |
2013 2014 2015 2016 2017 2018 |
* We do not need to take the global 'epumutex' on EPOLL_CTL_ADD when * the epoll file descriptor is attaching directly to a wakeup source, * unless the epoll file descriptor is nested. The purpose of taking the * 'epmutex' on add is to prevent complex toplogies such as loops and * deep wakeup paths from forming in parallel through multiple * EPOLL_CTL_ADD operations. |
22bacca48 epoll: prevent cr... |
2019 |
*/ |
39220e8d4 eventpoll: suppor... |
2020 2021 2022 |
error = epoll_mutex_lock(&ep->mtx, 0, nonblock); if (error) goto error_tgt_fput; |
28d82dc1c epoll: limit paths |
2023 |
if (op == EPOLL_CTL_ADD) { |
319c15174 epoll: take epite... |
2024 2025 |
if (READ_ONCE(f.file->f_ep) || ep->gen == loop_check_gen || is_file_epoll(tf.file)) { |
67347fe4e epoll: do not tak... |
2026 |
mutex_unlock(&ep->mtx); |
39220e8d4 eventpoll: suppor... |
2027 2028 2029 |
error = epoll_mutex_lock(&epmutex, 0, nonblock); if (error) goto error_tgt_fput; |
18306c404 epoll: replace ->... |
2030 |
loop_check_gen++; |
39220e8d4 eventpoll: suppor... |
2031 |
full_check = 1; |
67347fe4e epoll: do not tak... |
2032 |
if (is_file_epoll(tf.file)) { |
bde03c4c1 ep_loop_check_pro... |
2033 |
tep = tf.file->private_data; |
67347fe4e epoll: do not tak... |
2034 |
error = -ELOOP; |
bde03c4c1 ep_loop_check_pro... |
2035 |
if (ep_loop_check(ep, tep) != 0) |
67347fe4e epoll: do not tak... |
2036 |
goto error_tgt_fput; |
a9ed4a656 epoll: Keep a ref... |
2037 |
} |
39220e8d4 eventpoll: suppor... |
2038 |
error = epoll_mutex_lock(&ep->mtx, 0, nonblock); |
52c479697 do_epoll_ctl(): c... |
2039 |
if (error) |
39220e8d4 eventpoll: suppor... |
2040 |
goto error_tgt_fput; |
67347fe4e epoll: do not tak... |
2041 2042 |
} } |
7699acd13 epoll cleanups: e... |
2043 |
|
67647d0fb epoll: fix some c... |
2044 |
/* |
a6c67fee9 fs: eventpoll: fi... |
2045 |
* Try to lookup the file inside our RB tree. Since we grabbed "mtx" |
67647d0fb epoll: fix some c... |
2046 2047 2048 |
* above, we can be sure to be able to use the item looked up by * ep_find() till we release the mutex. */ |
7e3fb5842 switch epoll_ctl(... |
2049 |
epi = ep_find(ep, tf.file, fd); |
7699acd13 epoll cleanups: e... |
2050 2051 2052 2053 2054 |
error = -EINVAL; switch (op) { case EPOLL_CTL_ADD: if (!epi) { |
58e41a44c eventpoll: abstra... |
2055 2056 |
epds->events |= EPOLLERR | EPOLLHUP; error = ep_insert(ep, epds, tf.file, fd, full_check); |
7699acd13 epoll cleanups: e... |
2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 |
} else error = -EEXIST; break; case EPOLL_CTL_DEL: if (epi) error = ep_remove(ep, epi); else error = -ENOENT; break; case EPOLL_CTL_MOD: if (epi) { |
b6a515c8a epoll: restrict E... |
2068 |
if (!(epi->event.events & EPOLLEXCLUSIVE)) { |
58e41a44c eventpoll: abstra... |
2069 2070 |
epds->events |= EPOLLERR | EPOLLHUP; error = ep_modify(ep, epi, epds); |
b6a515c8a epoll: restrict E... |
2071 |
} |
7699acd13 epoll cleanups: e... |
2072 2073 2074 2075 |
} else error = -ENOENT; break; } |
d47de16c7 fix epoll single ... |
2076 |
mutex_unlock(&ep->mtx); |
7699acd13 epoll cleanups: e... |
2077 2078 |
error_tgt_fput: |
52c479697 do_epoll_ctl(): c... |
2079 2080 |
if (full_check) { clear_tfile_check_list(); |
18306c404 epoll: replace ->... |
2081 |
loop_check_gen++; |
22bacca48 epoll: prevent cr... |
2082 |
mutex_unlock(&epmutex); |
52c479697 do_epoll_ctl(): c... |
2083 |
} |
22bacca48 epoll: prevent cr... |
2084 |
|
7e3fb5842 switch epoll_ctl(... |
2085 |
fdput(tf); |
7699acd13 epoll cleanups: e... |
2086 |
error_fput: |
7e3fb5842 switch epoll_ctl(... |
2087 |
fdput(f); |
7699acd13 epoll cleanups: e... |
2088 |
error_return: |
7699acd13 epoll cleanups: e... |
2089 2090 2091 2092 2093 |
return error; } /* |
58e41a44c eventpoll: abstra... |
2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 |
* The following function implements the controller interface for * the eventpoll file that enables the insertion/removal/change of * file descriptors inside the interest set. */ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd, struct epoll_event __user *, event) { struct epoll_event epds; if (ep_op_has_event(op) && copy_from_user(&epds, event, sizeof(struct epoll_event))) return -EFAULT; |
39220e8d4 eventpoll: suppor... |
2106 |
return do_epoll_ctl(epfd, op, fd, &epds, false); |
58e41a44c eventpoll: abstra... |
2107 2108 2109 |
} /* |
7699acd13 epoll cleanups: e... |
2110 2111 2112 |
* Implement the event wait interface for the eventpoll file. It is the kernel * part of the user space epoll_wait(2). */ |
791eb22ee fs: add do_epoll_... |
2113 |
static int do_epoll_wait(int epfd, struct epoll_event __user *events, |
7cdf7c20e epoll: convert in... |
2114 |
int maxevents, struct timespec64 *to) |
7699acd13 epoll cleanups: e... |
2115 |
{ |
2903ff019 switch simple cas... |
2116 2117 |
int error; struct fd f; |
7699acd13 epoll cleanups: e... |
2118 |
struct eventpoll *ep; |
7699acd13 epoll cleanups: e... |
2119 2120 2121 2122 2123 |
/* The maximum number of event must be greater than zero */ if (maxevents <= 0 || maxevents > EP_MAX_EVENTS) return -EINVAL; /* Verify that the area passed by the user is writeable */ |
96d4f267e Remove 'type' arg... |
2124 |
if (!access_ok(events, maxevents * sizeof(struct epoll_event))) |
2903ff019 switch simple cas... |
2125 |
return -EFAULT; |
7699acd13 epoll cleanups: e... |
2126 2127 |
/* Get the "struct file *" for the eventpoll file */ |
2903ff019 switch simple cas... |
2128 2129 2130 |
f = fdget(epfd); if (!f.file) return -EBADF; |
7699acd13 epoll cleanups: e... |
2131 2132 2133 2134 2135 2136 |
/* * We have to check that the file structure underneath the fd * the user passed to us _is_ an eventpoll file. */ error = -EINVAL; |
2903ff019 switch simple cas... |
2137 |
if (!is_file_epoll(f.file)) |
7699acd13 epoll cleanups: e... |
2138 2139 2140 2141 2142 2143 |
goto error_fput; /* * At this point it is safe to assume that the "private_data" contains * our own data structure. */ |
2903ff019 switch simple cas... |
2144 |
ep = f.file->private_data; |
7699acd13 epoll cleanups: e... |
2145 2146 |
/* Time to fish for events ... */ |
7cdf7c20e epoll: convert in... |
2147 |
error = ep_poll(ep, events, maxevents, to); |
7699acd13 epoll cleanups: e... |
2148 2149 |
error_fput: |
2903ff019 switch simple cas... |
2150 |
fdput(f); |
7699acd13 epoll cleanups: e... |
2151 2152 |
return error; } |
791eb22ee fs: add do_epoll_... |
2153 2154 2155 |
SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events, int, maxevents, int, timeout) { |
7cdf7c20e epoll: convert in... |
2156 2157 2158 2159 |
struct timespec64 to; return do_epoll_wait(epfd, events, maxevents, ep_timeout_to_timespec(&to, timeout)); |
791eb22ee fs: add do_epoll_... |
2160 |
} |
7699acd13 epoll cleanups: e... |
2161 2162 2163 2164 |
/* * Implement the event wait interface for the eventpoll file. It is the kernel * part of the user space epoll_pwait(2). */ |
58169a52e epoll: add syscal... |
2165 2166 2167 |
static int do_epoll_pwait(int epfd, struct epoll_event __user *events, int maxevents, struct timespec64 *to, const sigset_t __user *sigmask, size_t sigsetsize) |
7699acd13 epoll cleanups: e... |
2168 2169 |
{ int error; |
7699acd13 epoll cleanups: e... |
2170 2171 2172 2173 2174 |
/* * If the caller wants a certain signal mask to be set during the wait, * we apply it here. */ |
b772434be signal: simplify ... |
2175 |
error = set_user_sigmask(sigmask, sigsetsize); |
ded653ccb signal: Add set_u... |
2176 2177 |
if (error) return error; |
7699acd13 epoll cleanups: e... |
2178 |
|
58169a52e epoll: add syscal... |
2179 |
error = do_epoll_wait(epfd, events, maxevents, to); |
7cdf7c20e epoll: convert in... |
2180 |
|
b772434be signal: simplify ... |
2181 |
restore_saved_sigmask_unless(error == -EINTR); |
7699acd13 epoll cleanups: e... |
2182 2183 2184 |
return error; } |
58169a52e epoll: add syscal... |
2185 2186 2187 |
SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events, int, maxevents, int, timeout, const sigset_t __user *, sigmask, size_t, sigsetsize) |
35280bd4a switch epoll_pwai... |
2188 |
{ |
7cdf7c20e epoll: convert in... |
2189 |
struct timespec64 to; |
58169a52e epoll: add syscal... |
2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 |
return do_epoll_pwait(epfd, events, maxevents, ep_timeout_to_timespec(&to, timeout), sigmask, sigsetsize); } SYSCALL_DEFINE6(epoll_pwait2, int, epfd, struct epoll_event __user *, events, int, maxevents, const struct __kernel_timespec __user *, timeout, const sigset_t __user *, sigmask, size_t, sigsetsize) { struct timespec64 ts, *to = NULL; if (timeout) { if (get_timespec64(&ts, timeout)) return -EFAULT; to = &ts; if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) return -EINVAL; } return do_epoll_pwait(epfd, events, maxevents, to, sigmask, sigsetsize); } #ifdef CONFIG_COMPAT static int do_compat_epoll_pwait(int epfd, struct epoll_event __user *events, int maxevents, struct timespec64 *timeout, const compat_sigset_t __user *sigmask, compat_size_t sigsetsize) { |
35280bd4a switch epoll_pwai... |
2220 |
long err; |
35280bd4a switch epoll_pwai... |
2221 2222 2223 2224 2225 |
/* * If the caller wants a certain signal mask to be set during the wait, * we apply it here. */ |
b772434be signal: simplify ... |
2226 |
err = set_compat_user_sigmask(sigmask, sigsetsize); |
ded653ccb signal: Add set_u... |
2227 2228 |
if (err) return err; |
35280bd4a switch epoll_pwai... |
2229 |
|
58169a52e epoll: add syscal... |
2230 |
err = do_epoll_wait(epfd, events, maxevents, timeout); |
7cdf7c20e epoll: convert in... |
2231 |
|
b772434be signal: simplify ... |
2232 |
restore_saved_sigmask_unless(err == -EINTR); |
35280bd4a switch epoll_pwai... |
2233 2234 2235 |
return err; } |
58169a52e epoll: add syscal... |
2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 |
COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events, int, maxevents, int, timeout, const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize) { struct timespec64 to; return do_compat_epoll_pwait(epfd, events, maxevents, ep_timeout_to_timespec(&to, timeout), sigmask, sigsetsize); } COMPAT_SYSCALL_DEFINE6(epoll_pwait2, int, epfd, struct epoll_event __user *, events, int, maxevents, const struct __kernel_timespec __user *, timeout, const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize) { struct timespec64 ts, *to = NULL; if (timeout) { if (get_timespec64(&ts, timeout)) return -EFAULT; to = &ts; if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) return -EINVAL; } return do_compat_epoll_pwait(epfd, events, maxevents, to, sigmask, sigsetsize); } |
35280bd4a switch epoll_pwai... |
2270 |
#endif |
1da177e4c Linux-2.6.12-rc2 |
2271 2272 |
static int __init eventpoll_init(void) { |
7ef9964e6 epoll: introduce ... |
2273 2274 2275 |
struct sysinfo si; si_meminfo(&si); |
9df04e1f2 epoll: drop max_u... |
2276 2277 2278 2279 |
/* * Allows top 4% of lomem to be allocated for epoll watches (per user). */ max_user_watches = (((si.totalram - si.totalhigh) / 25) << PAGE_SHIFT) / |
7ef9964e6 epoll: introduce ... |
2280 |
EP_ITEM_COST; |
52bd19f76 epoll: convert ma... |
2281 |
BUG_ON(max_user_watches < 0); |
1da177e4c Linux-2.6.12-rc2 |
2282 |
|
22bacca48 epoll: prevent cr... |
2283 |
/* |
39732ca5a epoll: trim epite... |
2284 2285 2286 2287 |
* We can have many thousands of epitems, so prevent this from * using an extra cache line on 64-bit (and smaller) CPUs */ BUILD_BUG_ON(sizeof(void *) <= 8 && sizeof(struct epitem) > 128); |
1da177e4c Linux-2.6.12-rc2 |
2288 2289 |
/* Allocates slab cache used to allocate "struct epitem" items */ epi_cache = kmem_cache_create("eventpoll_epi", sizeof(struct epitem), |
2ae928a94 epoll: account ep... |
2290 |
0, SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL); |
1da177e4c Linux-2.6.12-rc2 |
2291 2292 2293 |
/* Allocates slab cache used to allocate "struct eppoll_entry" */ pwq_cache = kmem_cache_create("eventpoll_pwq", |
2ae928a94 epoll: account ep... |
2294 |
sizeof(struct eppoll_entry), 0, SLAB_PANIC|SLAB_ACCOUNT, NULL); |
1da177e4c Linux-2.6.12-rc2 |
2295 |
|
319c15174 epoll: take epite... |
2296 2297 |
ephead_cache = kmem_cache_create("ep_head", sizeof(struct epitems_head), 0, SLAB_PANIC|SLAB_ACCOUNT, NULL); |
1da177e4c Linux-2.6.12-rc2 |
2298 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
2299 |
} |
cea692418 epoll cleanups: e... |
2300 |
fs_initcall(eventpoll_init); |