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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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|
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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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|
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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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|
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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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* Structure used to track possible nested calls, for too deep recursions * and loop cycles. |
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*/ |
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struct nested_call_node { |
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struct list_head llink; |
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void *cookie; |
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void *ctx; |
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}; /* |
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* This structure is used as collector for nested calls, to check for * maximum recursion dept and loop cycles. |
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*/ |
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struct nested_calls { struct list_head tasks_call_list; |
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spinlock_t lock; }; /* |
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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; /* Number of active wait queue attached to poll operations */ int nwait; /* List containing poll wait queues */ struct list_head pwqlist; /* 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 */ struct list_head 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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|
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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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|
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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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#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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}; /* Wait structure used by the poll hooks */ struct eppoll_entry { /* List header used to link this structure to the "struct epitem" */ struct list_head llink; /* The "base" pointer is set to the container "struct epitem" */ |
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struct epitem *base; |
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/* * Wait queue item that will be linked to the target file wait * queue head. */ |
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wait_queue_entry_t wait; |
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/* The wait queue head that linked the "wait" wait queue item */ wait_queue_head_t *whead; }; |
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/* Wrapper struct used by poll queueing */ struct ep_pqueue { poll_table pt; struct epitem *epi; }; |
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/* Used by the ep_send_events() function as callback private data */ struct ep_send_events_data { int maxevents; struct epoll_event __user *events; |
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int res; |
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}; |
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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 */ static struct nested_calls poll_loop_ncalls; |
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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. */ static LIST_HEAD(tfile_check_list); |
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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; } /* Get the "struct epitem" from an epoll queue wrapper */ |
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static inline struct epitem *ep_item_from_epqueue(poll_table *p) |
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{ return container_of(p, struct ep_pqueue, pt)->epi; } |
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/* Initialize the poll safe wake up structure */ |
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static void ep_nested_calls_init(struct nested_calls *ncalls) |
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{ |
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INIT_LIST_HEAD(&ncalls->tasks_call_list); spin_lock_init(&ncalls->lock); |
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} |
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/** |
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* ep_events_available - Checks if ready events might be available. * * @ep: Pointer to the eventpoll context. * * Returns: Returns a value different than zero if ready events are available, * or zero otherwise. */ 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 */ static void ep_busy_loop(struct eventpoll *ep, int nonblock) { |
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unsigned int napi_id = READ_ONCE(ep->napi_id); if ((napi_id >= MIN_NAPI_ID) && net_busy_loop_on()) napi_busy_loop(napi_id, nonblock ? NULL : ep_busy_loop_end, ep); |
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} static inline void ep_reset_busy_poll_napi_id(struct eventpoll *ep) { |
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if (ep->napi_id) ep->napi_id = 0; |
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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; int err; if (!net_busy_loop_on()) return; sock = sock_from_file(epi->ffd.file, &err); 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 static inline void ep_busy_loop(struct eventpoll *ep, int nonblock) { } static inline void ep_reset_busy_poll_napi_id(struct eventpoll *ep) { } static inline void ep_set_busy_poll_napi_id(struct epitem *epi) { } #endif /* CONFIG_NET_RX_BUSY_POLL */ |
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/** |
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* ep_call_nested - Perform a bound (possibly) nested call, by checking * that the recursion limit is not exceeded, and that * the same nested call (by the meaning of same cookie) is * no re-entered. * * @ncalls: Pointer to the nested_calls structure to be used for this call. |
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* @nproc: Nested call core function pointer. * @priv: Opaque data to be passed to the @nproc callback. * @cookie: Cookie to be used to identify this nested call. |
3fe4a975d epoll: fix nested... |
441 |
* @ctx: This instance context. |
5071f97ec epoll: fix epoll'... |
442 443 444 |
* * Returns: Returns the code returned by the @nproc callback, or -1 if * the maximum recursion limit has been exceeded. |
1da177e4c Linux-2.6.12-rc2 |
445 |
*/ |
74bdc1298 fs/epoll: remove ... |
446 |
static int ep_call_nested(struct nested_calls *ncalls, |
5071f97ec epoll: fix epoll'... |
447 |
int (*nproc)(void *, void *, int), void *priv, |
3fe4a975d epoll: fix nested... |
448 |
void *cookie, void *ctx) |
1da177e4c Linux-2.6.12-rc2 |
449 |
{ |
5071f97ec epoll: fix epoll'... |
450 |
int error, call_nests = 0; |
1da177e4c Linux-2.6.12-rc2 |
451 |
unsigned long flags; |
5071f97ec epoll: fix epoll'... |
452 453 454 |
struct list_head *lsthead = &ncalls->tasks_call_list; struct nested_call_node *tncur; struct nested_call_node tnode; |
1da177e4c Linux-2.6.12-rc2 |
455 |
|
5071f97ec epoll: fix epoll'... |
456 |
spin_lock_irqsave(&ncalls->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
457 |
|
5071f97ec epoll: fix epoll'... |
458 459 460 461 462 |
/* * Try to see if the current task is already inside this wakeup call. * We use a list here, since the population inside this set is always * very much limited. */ |
b70c39409 fs/eventpoll.c: u... |
463 |
list_for_each_entry(tncur, lsthead, llink) { |
3fe4a975d epoll: fix nested... |
464 |
if (tncur->ctx == ctx && |
74bdc1298 fs/epoll: remove ... |
465 |
(tncur->cookie == cookie || ++call_nests > EP_MAX_NESTS)) { |
1da177e4c Linux-2.6.12-rc2 |
466 467 468 469 |
/* * Ops ... loop detected or maximum nest level reached. * We abort this wake by breaking the cycle itself. */ |
abff55cee epoll: don't use ... |
470 471 |
error = -1; goto out_unlock; |
1da177e4c Linux-2.6.12-rc2 |
472 473 |
} } |
5071f97ec epoll: fix epoll'... |
474 |
/* Add the current task and cookie to the list */ |
3fe4a975d epoll: fix nested... |
475 |
tnode.ctx = ctx; |
5071f97ec epoll: fix epoll'... |
476 |
tnode.cookie = cookie; |
1da177e4c Linux-2.6.12-rc2 |
477 |
list_add(&tnode.llink, lsthead); |
5071f97ec epoll: fix epoll'... |
478 |
spin_unlock_irqrestore(&ncalls->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
479 |
|
5071f97ec epoll: fix epoll'... |
480 481 |
/* Call the nested function */ error = (*nproc)(priv, cookie, call_nests); |
1da177e4c Linux-2.6.12-rc2 |
482 483 |
/* Remove the current task from the list */ |
5071f97ec epoll: fix epoll'... |
484 |
spin_lock_irqsave(&ncalls->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
485 |
list_del(&tnode.llink); |
3fe4a975d epoll: fix nested... |
486 |
out_unlock: |
5071f97ec epoll: fix epoll'... |
487 488 489 490 |
spin_unlock_irqrestore(&ncalls->lock, flags); return error; } |
02edc6fc4 epoll: comment th... |
491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 |
/* * 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. */ |
2dfa4eeab epoll keyed wakeu... |
516 |
#ifdef CONFIG_DEBUG_LOCK_ALLOC |
57a173bdf epoll: avoid call... |
517 |
|
efcdd350d fs/epoll: make ne... |
518 |
static void ep_poll_safewake(struct eventpoll *ep, struct epitem *epi) |
5071f97ec epoll: fix epoll'... |
519 |
{ |
efcdd350d fs/epoll: make ne... |
520 |
struct eventpoll *ep_src; |
f6520c520 epoll: simplify e... |
521 |
unsigned long flags; |
efcdd350d fs/epoll: make ne... |
522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 |
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); |
1da177e4c Linux-2.6.12-rc2 |
552 |
} |
57a173bdf epoll: avoid call... |
553 |
#else |
efcdd350d fs/epoll: make ne... |
554 |
static void ep_poll_safewake(struct eventpoll *ep, struct epitem *epi) |
57a173bdf epoll: avoid call... |
555 |
{ |
efcdd350d fs/epoll: make ne... |
556 |
wake_up_poll(&ep->poll_wait, EPOLLIN); |
57a173bdf epoll: avoid call... |
557 558 559 |
} #endif |
971316f05 epoll: ep_unregis... |
560 561 562 563 564 |
static void ep_remove_wait_queue(struct eppoll_entry *pwq) { wait_queue_head_t *whead; rcu_read_lock(); |
138e4ad67 epoll: fix race b... |
565 566 567 568 569 570 571 |
/* * 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... |
572 573 574 575 |
if (whead) remove_wait_queue(whead, &pwq->wait); rcu_read_unlock(); } |
1da177e4c Linux-2.6.12-rc2 |
576 |
/* |
d1bc90dd5 epoll: remove unn... |
577 578 579 |
* This function unregisters poll callbacks from the associated file * descriptor. Must be called with "mtx" held (or "epmutex" if called from * ep_free). |
1da177e4c Linux-2.6.12-rc2 |
580 |
*/ |
7699acd13 epoll cleanups: e... |
581 |
static void ep_unregister_pollwait(struct eventpoll *ep, struct epitem *epi) |
1da177e4c Linux-2.6.12-rc2 |
582 |
{ |
7699acd13 epoll cleanups: e... |
583 584 |
struct list_head *lsthead = &epi->pwqlist; struct eppoll_entry *pwq; |
1da177e4c Linux-2.6.12-rc2 |
585 |
|
d1bc90dd5 epoll: remove unn... |
586 587 |
while (!list_empty(lsthead)) { pwq = list_first_entry(lsthead, struct eppoll_entry, llink); |
1da177e4c Linux-2.6.12-rc2 |
588 |
|
d1bc90dd5 epoll: remove unn... |
589 |
list_del(&pwq->llink); |
971316f05 epoll: ep_unregis... |
590 |
ep_remove_wait_queue(pwq); |
d1bc90dd5 epoll: remove unn... |
591 |
kmem_cache_free(pwq_cache, pwq); |
1da177e4c Linux-2.6.12-rc2 |
592 |
} |
1da177e4c Linux-2.6.12-rc2 |
593 |
} |
eea1d5859 epoll: use RCU to... |
594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 |
/* 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(); } |
5071f97ec epoll: fix epoll'... |
625 626 627 628 629 630 631 632 |
/** * ep_scan_ready_list - Scans the ready list in a way that makes possible for * the scan code, to call f_op->poll(). Also allows for * O(NumReady) performance. * * @ep: Pointer to the epoll private data structure. * @sproc: Pointer to the scan callback. * @priv: Private opaque data passed to the @sproc callback. |
d8805e633 epoll: fix spurio... |
633 |
* @depth: The current depth of recursive f_op->poll calls. |
67347fe4e epoll: do not tak... |
634 |
* @ep_locked: caller already holds ep->mtx |
5071f97ec epoll: fix epoll'... |
635 636 637 |
* * Returns: The same integer error code returned by the @sproc callback. */ |
d85e2aa2e annotate ep_scan_... |
638 639 |
static __poll_t ep_scan_ready_list(struct eventpoll *ep, __poll_t (*sproc)(struct eventpoll *, |
5071f97ec epoll: fix epoll'... |
640 |
struct list_head *, void *), |
67347fe4e epoll: do not tak... |
641 |
void *priv, int depth, bool ep_locked) |
5071f97ec epoll: fix epoll'... |
642 |
{ |
d85e2aa2e annotate ep_scan_... |
643 |
__poll_t res; |
5071f97ec epoll: fix epoll'... |
644 |
struct epitem *epi, *nepi; |
296e236e9 epoll: fix epoll'... |
645 |
LIST_HEAD(txlist); |
5071f97ec epoll: fix epoll'... |
646 |
|
92e641784 s/epoll: robustif... |
647 |
lockdep_assert_irqs_enabled(); |
5071f97ec epoll: fix epoll'... |
648 649 |
/* * We need to lock this because we could be hit by |
e057e15ff epoll: clean up e... |
650 |
* eventpoll_release_file() and epoll_ctl(). |
5071f97ec epoll: fix epoll'... |
651 |
*/ |
67347fe4e epoll: do not tak... |
652 653 654 |
if (!ep_locked) mutex_lock_nested(&ep->mtx, depth); |
5071f97ec epoll: fix epoll'... |
655 656 657 658 659 660 661 662 663 |
/* * 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. */ |
a218cc491 epoll: use rwlock... |
664 |
write_lock_irq(&ep->lock); |
296e236e9 epoll: fix epoll'... |
665 |
list_splice_init(&ep->rdllist, &txlist); |
c5a282e96 fs/epoll: reduce ... |
666 |
WRITE_ONCE(ep->ovflist, NULL); |
a218cc491 epoll: use rwlock... |
667 |
write_unlock_irq(&ep->lock); |
5071f97ec epoll: fix epoll'... |
668 669 670 671 |
/* * Now call the callback function. */ |
d85e2aa2e annotate ep_scan_... |
672 |
res = (*sproc)(ep, &txlist, priv); |
5071f97ec epoll: fix epoll'... |
673 |
|
a218cc491 epoll: use rwlock... |
674 |
write_lock_irq(&ep->lock); |
5071f97ec epoll: fix epoll'... |
675 676 677 678 679 |
/* * 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 ... |
680 |
for (nepi = READ_ONCE(ep->ovflist); (epi = nepi) != NULL; |
5071f97ec epoll: fix epoll'... |
681 682 683 684 685 686 687 |
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... |
688 |
if (!ep_is_linked(epi)) { |
c141175d0 epoll: make sure ... |
689 690 691 692 693 |
/* * ->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... |
694 |
ep_pm_stay_awake(epi); |
4d7e30d98 epoll: Add a flag... |
695 |
} |
5071f97ec epoll: fix epoll'... |
696 697 698 699 700 701 |
} /* * 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 ... |
702 |
WRITE_ONCE(ep->ovflist, EP_UNACTIVE_PTR); |
5071f97ec epoll: fix epoll'... |
703 704 705 706 707 |
/* * Quickly re-inject items left on "txlist". */ list_splice(&txlist, &ep->rdllist); |
4d7e30d98 epoll: Add a flag... |
708 |
__pm_relax(ep->ws); |
a218cc491 epoll: use rwlock... |
709 |
write_unlock_irq(&ep->lock); |
5071f97ec epoll: fix epoll'... |
710 |
|
67347fe4e epoll: do not tak... |
711 712 |
if (!ep_locked) mutex_unlock(&ep->mtx); |
5071f97ec epoll: fix epoll'... |
713 |
|
d85e2aa2e annotate ep_scan_... |
714 |
return res; |
5071f97ec epoll: fix epoll'... |
715 |
} |
ae10b2b4e epoll: optimize E... |
716 717 718 719 720 |
static void epi_rcu_free(struct rcu_head *head) { struct epitem *epi = container_of(head, struct epitem, rcu); kmem_cache_free(epi_cache, epi); } |
1da177e4c Linux-2.6.12-rc2 |
721 |
/* |
7699acd13 epoll cleanups: e... |
722 |
* Removes a "struct epitem" from the eventpoll RB tree and deallocates |
c7ea76302 epoll locks chang... |
723 |
* all the associated resources. Must be called with "mtx" held. |
7699acd13 epoll cleanups: e... |
724 725 726 |
*/ static int ep_remove(struct eventpoll *ep, struct epitem *epi) { |
7699acd13 epoll cleanups: e... |
727 |
struct file *file = epi->ffd.file; |
1da177e4c Linux-2.6.12-rc2 |
728 |
|
92e641784 s/epoll: robustif... |
729 |
lockdep_assert_irqs_enabled(); |
1da177e4c Linux-2.6.12-rc2 |
730 |
/* |
ee8ef0a4b epoll: use the wa... |
731 |
* Removes poll wait queue hooks. |
1da177e4c Linux-2.6.12-rc2 |
732 |
*/ |
7699acd13 epoll cleanups: e... |
733 |
ep_unregister_pollwait(ep, epi); |
1da177e4c Linux-2.6.12-rc2 |
734 |
|
7699acd13 epoll cleanups: e... |
735 |
/* Remove the current item from the list of epoll hooks */ |
684999149 Rename struct fil... |
736 |
spin_lock(&file->f_lock); |
ae10b2b4e epoll: optimize E... |
737 |
list_del_rcu(&epi->fllink); |
684999149 Rename struct fil... |
738 |
spin_unlock(&file->f_lock); |
1da177e4c Linux-2.6.12-rc2 |
739 |
|
b2ac2ea62 fs/epoll: use fas... |
740 |
rb_erase_cached(&epi->rbn, &ep->rbr); |
1da177e4c Linux-2.6.12-rc2 |
741 |
|
a218cc491 epoll: use rwlock... |
742 |
write_lock_irq(&ep->lock); |
992991c03 fs/eventpoll.c: s... |
743 |
if (ep_is_linked(epi)) |
c7ea76302 epoll locks chang... |
744 |
list_del_init(&epi->rdllink); |
a218cc491 epoll: use rwlock... |
745 |
write_unlock_irq(&ep->lock); |
1da177e4c Linux-2.6.12-rc2 |
746 |
|
eea1d5859 epoll: use RCU to... |
747 |
wakeup_source_unregister(ep_wakeup_source(epi)); |
ae10b2b4e epoll: optimize E... |
748 749 750 751 752 753 754 755 |
/* * 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); |
1da177e4c Linux-2.6.12-rc2 |
756 |
|
52bd19f76 epoll: convert ma... |
757 |
atomic_long_dec(&ep->user->epoll_watches); |
7ef9964e6 epoll: introduce ... |
758 |
|
c7ea76302 epoll locks chang... |
759 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
760 |
} |
7699acd13 epoll cleanups: e... |
761 |
static void ep_free(struct eventpoll *ep) |
1da177e4c Linux-2.6.12-rc2 |
762 |
{ |
7699acd13 epoll cleanups: e... |
763 764 |
struct rb_node *rbp; struct epitem *epi; |
1da177e4c Linux-2.6.12-rc2 |
765 |
|
7699acd13 epoll cleanups: e... |
766 767 |
/* We need to release all tasks waiting for these file */ if (waitqueue_active(&ep->poll_wait)) |
efcdd350d fs/epoll: make ne... |
768 |
ep_poll_safewake(ep, NULL); |
1da177e4c Linux-2.6.12-rc2 |
769 |
|
7699acd13 epoll cleanups: e... |
770 771 772 |
/* * 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 ... |
773 |
* We do not need to hold "ep->mtx" here because the epoll file |
7699acd13 epoll cleanups: e... |
774 775 |
* 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... |
776 |
* holding "epmutex" is sufficient here. |
7699acd13 epoll cleanups: e... |
777 778 |
*/ mutex_lock(&epmutex); |
1da177e4c Linux-2.6.12-rc2 |
779 780 |
/* |
7699acd13 epoll cleanups: e... |
781 |
* Walks through the whole tree by unregistering poll callbacks. |
1da177e4c Linux-2.6.12-rc2 |
782 |
*/ |
b2ac2ea62 fs/epoll: use fas... |
783 |
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
7699acd13 epoll cleanups: e... |
784 785 786 |
epi = rb_entry(rbp, struct epitem, rbn); ep_unregister_pollwait(ep, epi); |
91cf5ab60 epoll: add a resc... |
787 |
cond_resched(); |
7699acd13 epoll cleanups: e... |
788 |
} |
1da177e4c Linux-2.6.12-rc2 |
789 790 |
/* |
7699acd13 epoll cleanups: e... |
791 792 |
* 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 ... |
793 |
* holding "epmutex" we can be sure that no file cleanup code will hit |
a218cc491 epoll: use rwlock... |
794 |
* us during this operation. So we can avoid the lock on "ep->lock". |
ddf676c38 epoll: lock ep->m... |
795 796 |
* We do not need to lock ep->mtx, either, we only do it to prevent * a lockdep warning. |
1da177e4c Linux-2.6.12-rc2 |
797 |
*/ |
ddf676c38 epoll: lock ep->m... |
798 |
mutex_lock(&ep->mtx); |
b2ac2ea62 fs/epoll: use fas... |
799 |
while ((rbp = rb_first_cached(&ep->rbr)) != NULL) { |
7699acd13 epoll cleanups: e... |
800 801 |
epi = rb_entry(rbp, struct epitem, rbn); ep_remove(ep, epi); |
91cf5ab60 epoll: add a resc... |
802 |
cond_resched(); |
7699acd13 epoll cleanups: e... |
803 |
} |
ddf676c38 epoll: lock ep->m... |
804 |
mutex_unlock(&ep->mtx); |
1da177e4c Linux-2.6.12-rc2 |
805 |
|
7699acd13 epoll cleanups: e... |
806 |
mutex_unlock(&epmutex); |
d47de16c7 fix epoll single ... |
807 |
mutex_destroy(&ep->mtx); |
7ef9964e6 epoll: introduce ... |
808 |
free_uid(ep->user); |
4d7e30d98 epoll: Add a flag... |
809 |
wakeup_source_unregister(ep->ws); |
f0ee9aabb epoll: move kfree... |
810 |
kfree(ep); |
7699acd13 epoll cleanups: e... |
811 |
} |
1da177e4c Linux-2.6.12-rc2 |
812 |
|
7699acd13 epoll cleanups: e... |
813 814 815 |
static int ep_eventpoll_release(struct inode *inode, struct file *file) { struct eventpoll *ep = file->private_data; |
1da177e4c Linux-2.6.12-rc2 |
816 |
|
f0ee9aabb epoll: move kfree... |
817 |
if (ep) |
7699acd13 epoll cleanups: e... |
818 |
ep_free(ep); |
7699acd13 epoll cleanups: e... |
819 |
|
7699acd13 epoll cleanups: e... |
820 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
821 |
} |
d85e2aa2e annotate ep_scan_... |
822 |
static __poll_t ep_read_events_proc(struct eventpoll *ep, struct list_head *head, |
37b5e5212 epoll: remove ep_... |
823 824 825 826 827 828 829 830 831 |
void *priv); static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead, poll_table *pt); /* * 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_... |
832 |
static __poll_t ep_item_poll(const struct epitem *epi, poll_table *pt, |
bec1a502d eventpoll: consti... |
833 |
int depth) |
450d89ec0 epoll: cleanup: h... |
834 |
{ |
37b5e5212 epoll: remove ep_... |
835 836 |
struct eventpoll *ep; bool locked; |
450d89ec0 epoll: cleanup: h... |
837 |
pt->_key = epi->event.events; |
37b5e5212 epoll: remove ep_... |
838 |
if (!is_file_epoll(epi->ffd.file)) |
9965ed174 fs: add new vfs_p... |
839 |
return vfs_poll(epi->ffd.file, pt) & epi->event.events; |
450d89ec0 epoll: cleanup: h... |
840 |
|
37b5e5212 epoll: remove ep_... |
841 842 843 |
ep = epi->ffd.file->private_data; poll_wait(epi->ffd.file, &ep->poll_wait, pt); locked = pt && (pt->_qproc == ep_ptable_queue_proc); |
450d89ec0 epoll: cleanup: h... |
844 |
|
37b5e5212 epoll: remove ep_... |
845 846 847 |
return ep_scan_ready_list(epi->ffd.file->private_data, ep_read_events_proc, &depth, depth, locked) & epi->event.events; |
450d89ec0 epoll: cleanup: h... |
848 |
} |
d85e2aa2e annotate ep_scan_... |
849 |
static __poll_t ep_read_events_proc(struct eventpoll *ep, struct list_head *head, |
296e236e9 epoll: fix epoll'... |
850 |
void *priv) |
5071f97ec epoll: fix epoll'... |
851 852 |
{ struct epitem *epi, *tmp; |
626cf2366 poll: add poll_re... |
853 |
poll_table pt; |
37b5e5212 epoll: remove ep_... |
854 |
int depth = *(int *)priv; |
5071f97ec epoll: fix epoll'... |
855 |
|
626cf2366 poll: add poll_re... |
856 |
init_poll_funcptr(&pt, NULL); |
37b5e5212 epoll: remove ep_... |
857 |
depth++; |
450d89ec0 epoll: cleanup: h... |
858 |
|
5071f97ec epoll: fix epoll'... |
859 |
list_for_each_entry_safe(epi, tmp, head, rdllink) { |
37b5e5212 epoll: remove ep_... |
860 |
if (ep_item_poll(epi, &pt, depth)) { |
a9a08845e vfs: do bulk POLL... |
861 |
return EPOLLIN | EPOLLRDNORM; |
37b5e5212 epoll: remove ep_... |
862 |
} else { |
5071f97ec epoll: fix epoll'... |
863 864 865 866 867 |
/* * 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... |
868 |
__pm_relax(ep_wakeup_source(epi)); |
5071f97ec epoll: fix epoll'... |
869 |
list_del_init(&epi->rdllink); |
296e236e9 epoll: fix epoll'... |
870 |
} |
5071f97ec epoll: fix epoll'... |
871 872 873 874 |
} return 0; } |
a11e1d432 Revert changes to... |
875 |
static __poll_t ep_eventpoll_poll(struct file *file, poll_table *wait) |
11c5ad0ec eventpoll: switch... |
876 877 878 |
{ struct eventpoll *ep = file->private_data; int depth = 0; |
7699acd13 epoll cleanups: e... |
879 |
|
a11e1d432 Revert changes to... |
880 881 |
/* Insert inside our poll wait queue */ poll_wait(file, &ep->poll_wait, wait); |
5071f97ec epoll: fix epoll'... |
882 883 |
/* * Proceed to find out if wanted events are really available inside |
37b5e5212 epoll: remove ep_... |
884 |
* the ready list. |
5071f97ec epoll: fix epoll'... |
885 |
*/ |
37b5e5212 epoll: remove ep_... |
886 887 |
return ep_scan_ready_list(ep, ep_read_events_proc, &depth, depth, false); |
7699acd13 epoll cleanups: e... |
888 |
} |
138d22b58 fs, epoll: add pr... |
889 |
#ifdef CONFIG_PROC_FS |
a3816ab0e fs: Convert show_... |
890 |
static void ep_show_fdinfo(struct seq_file *m, struct file *f) |
138d22b58 fs, epoll: add pr... |
891 892 893 |
{ struct eventpoll *ep = f->private_data; struct rb_node *rbp; |
138d22b58 fs, epoll: add pr... |
894 895 |
mutex_lock(&ep->mtx); |
b2ac2ea62 fs/epoll: use fas... |
896 |
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
138d22b58 fs, epoll: add pr... |
897 |
struct epitem *epi = rb_entry(rbp, struct epitem, rbn); |
77493f04b procfs: fdinfo: e... |
898 |
struct inode *inode = file_inode(epi->ffd.file); |
138d22b58 fs, epoll: add pr... |
899 |
|
77493f04b procfs: fdinfo: e... |
900 901 902 |
seq_printf(m, "tfd: %8d events: %8x data: %16llx " " pos:%lli ino:%lx sdev:%x ", |
a3816ab0e fs: Convert show_... |
903 |
epi->ffd.fd, epi->event.events, |
77493f04b procfs: fdinfo: e... |
904 905 906 |
(long long)epi->event.data, (long long)epi->ffd.file->f_pos, inode->i_ino, inode->i_sb->s_dev); |
a3816ab0e fs: Convert show_... |
907 |
if (seq_has_overflowed(m)) |
138d22b58 fs, epoll: add pr... |
908 909 910 |
break; } mutex_unlock(&ep->mtx); |
138d22b58 fs, epoll: add pr... |
911 912 |
} #endif |
7699acd13 epoll cleanups: e... |
913 914 |
/* File callbacks that implement the eventpoll file behaviour */ static const struct file_operations eventpoll_fops = { |
138d22b58 fs, epoll: add pr... |
915 916 917 |
#ifdef CONFIG_PROC_FS .show_fdinfo = ep_show_fdinfo, #endif |
7699acd13 epoll cleanups: e... |
918 |
.release = ep_eventpoll_release, |
a11e1d432 Revert changes to... |
919 |
.poll = ep_eventpoll_poll, |
6038f373a llseek: automatic... |
920 |
.llseek = noop_llseek, |
7699acd13 epoll cleanups: e... |
921 |
}; |
b611967de [PATCH] epoll_pwa... |
922 |
/* |
7699acd13 epoll cleanups: e... |
923 924 925 |
* 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... |
926 |
*/ |
7699acd13 epoll cleanups: e... |
927 |
void eventpoll_release_file(struct file *file) |
b611967de [PATCH] epoll_pwa... |
928 |
{ |
7699acd13 epoll cleanups: e... |
929 |
struct eventpoll *ep; |
ebe06187b epoll: fix use-af... |
930 |
struct epitem *epi, *next; |
b611967de [PATCH] epoll_pwa... |
931 932 |
/* |
684999149 Rename struct fil... |
933 |
* We don't want to get "file->f_lock" because it is not |
7699acd13 epoll cleanups: e... |
934 |
* necessary. It is not necessary because we're in the "struct file" |
25985edce Fix common misspe... |
935 |
* cleanup path, and this means that no one is using this file anymore. |
5071f97ec epoll: fix epoll'... |
936 |
* So, for example, epoll_ctl() cannot hit here since if we reach this |
67647d0fb epoll: fix some c... |
937 |
* point, the file counter already went to zero and fget() would fail. |
d47de16c7 fix epoll single ... |
938 |
* The only hit might come from ep_free() but by holding the mutex |
7699acd13 epoll cleanups: e... |
939 |
* will correctly serialize the operation. We do need to acquire |
d47de16c7 fix epoll single ... |
940 |
* "ep->mtx" after "epmutex" because ep_remove() requires it when called |
7699acd13 epoll cleanups: e... |
941 |
* from anywhere but ep_free(). |
684999149 Rename struct fil... |
942 943 |
* * Besides, ep_remove() acquires the lock, so we can't hold it here. |
b611967de [PATCH] epoll_pwa... |
944 |
*/ |
7699acd13 epoll cleanups: e... |
945 |
mutex_lock(&epmutex); |
ebe06187b epoll: fix use-af... |
946 |
list_for_each_entry_safe(epi, next, &file->f_ep_links, fllink) { |
7699acd13 epoll cleanups: e... |
947 |
ep = epi->ep; |
d8805e633 epoll: fix spurio... |
948 |
mutex_lock_nested(&ep->mtx, 0); |
7699acd13 epoll cleanups: e... |
949 |
ep_remove(ep, epi); |
d47de16c7 fix epoll single ... |
950 |
mutex_unlock(&ep->mtx); |
b611967de [PATCH] epoll_pwa... |
951 |
} |
7699acd13 epoll cleanups: e... |
952 |
mutex_unlock(&epmutex); |
b611967de [PATCH] epoll_pwa... |
953 |
} |
53d2be79d [PATCH] epoll: fi... |
954 |
static int ep_alloc(struct eventpoll **pep) |
1da177e4c Linux-2.6.12-rc2 |
955 |
{ |
7ef9964e6 epoll: introduce ... |
956 957 958 |
int error; struct user_struct *user; struct eventpoll *ep; |
1da177e4c Linux-2.6.12-rc2 |
959 |
|
7ef9964e6 epoll: introduce ... |
960 |
user = get_current_user(); |
7ef9964e6 epoll: introduce ... |
961 962 963 964 |
error = -ENOMEM; ep = kzalloc(sizeof(*ep), GFP_KERNEL); if (unlikely(!ep)) goto free_uid; |
1da177e4c Linux-2.6.12-rc2 |
965 |
|
d47de16c7 fix epoll single ... |
966 |
mutex_init(&ep->mtx); |
a218cc491 epoll: use rwlock... |
967 |
rwlock_init(&ep->lock); |
1da177e4c Linux-2.6.12-rc2 |
968 969 970 |
init_waitqueue_head(&ep->wq); init_waitqueue_head(&ep->poll_wait); INIT_LIST_HEAD(&ep->rdllist); |
b2ac2ea62 fs/epoll: use fas... |
971 |
ep->rbr = RB_ROOT_CACHED; |
d47de16c7 fix epoll single ... |
972 |
ep->ovflist = EP_UNACTIVE_PTR; |
7ef9964e6 epoll: introduce ... |
973 |
ep->user = user; |
1da177e4c Linux-2.6.12-rc2 |
974 |
|
53d2be79d [PATCH] epoll: fi... |
975 |
*pep = ep; |
1da177e4c Linux-2.6.12-rc2 |
976 |
|
1da177e4c Linux-2.6.12-rc2 |
977 |
return 0; |
7ef9964e6 epoll: introduce ... |
978 979 980 981 |
free_uid: free_uid(user); return error; |
1da177e4c Linux-2.6.12-rc2 |
982 |
} |
1da177e4c Linux-2.6.12-rc2 |
983 |
/* |
c7ea76302 epoll locks chang... |
984 985 986 |
* 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 |
987 988 989 990 |
*/ static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd) { int kcmp; |
1da177e4c Linux-2.6.12-rc2 |
991 992 993 |
struct rb_node *rbp; struct epitem *epi, *epir = NULL; struct epoll_filefd ffd; |
b030a4dd6 [PATCH] Remove ev... |
994 |
ep_set_ffd(&ffd, file, fd); |
b2ac2ea62 fs/epoll: use fas... |
995 |
for (rbp = ep->rbr.rb_root.rb_node; rbp; ) { |
1da177e4c Linux-2.6.12-rc2 |
996 |
epi = rb_entry(rbp, struct epitem, rbn); |
b030a4dd6 [PATCH] Remove ev... |
997 |
kcmp = ep_cmp_ffd(&ffd, &epi->ffd); |
1da177e4c Linux-2.6.12-rc2 |
998 999 1000 1001 1002 |
if (kcmp > 0) rbp = rbp->rb_right; else if (kcmp < 0) rbp = rbp->rb_left; else { |
1da177e4c Linux-2.6.12-rc2 |
1003 1004 1005 1006 |
epir = epi; break; } } |
1da177e4c Linux-2.6.12-rc2 |
1007 |
|
1da177e4c Linux-2.6.12-rc2 |
1008 1009 |
return epir; } |
92ef6da3d kcmp: fs/epoll: w... |
1010 |
#ifdef CONFIG_CHECKPOINT_RESTORE |
0791e3644 kcmp: add KCMP_EP... |
1011 1012 1013 1014 |
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... |
1015 |
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
0791e3644 kcmp: add KCMP_EP... |
1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 |
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; } |
92ef6da3d kcmp: fs/epoll: w... |
1051 |
#endif /* CONFIG_CHECKPOINT_RESTORE */ |
0791e3644 kcmp: add KCMP_EP... |
1052 |
|
a218cc491 epoll: use rwlock... |
1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 |
/** * 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 * direction i.e. either to the tail either to the head, otherwise * concurrent access will corrupt the list. * * Returns %false if element has been already added to the list, %true * 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; } /** * 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. * * Returns %false if epi element has been already chained, %true otherwise. */ static inline bool chain_epi_lockless(struct epitem *epi) { struct eventpoll *ep = epi->ep; |
0c54a6a44 eventpoll: fix mi... |
1115 1116 1117 |
/* Fast preliminary check */ if (epi->next != EP_UNACTIVE_PTR) return false; |
a218cc491 epoll: use rwlock... |
1118 1119 1120 1121 1122 1123 1124 1125 1126 |
/* 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 |
1127 |
/* |
7699acd13 epoll cleanups: e... |
1128 |
* This is the callback that is passed to the wait queue wakeup |
bf6a41db7 fs/eventpoll.c: f... |
1129 |
* mechanism. It is called by the stored file descriptors when they |
7699acd13 epoll cleanups: e... |
1130 |
* have events to report. |
a218cc491 epoll: use rwlock... |
1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 |
* * This callback takes a read lock in order not to content with concurrent * events from another file descriptors, thus all modifications to ->rdllist * 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 |
1144 |
*/ |
ac6424b98 sched/wait: Renam... |
1145 |
static int ep_poll_callback(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) |
1da177e4c Linux-2.6.12-rc2 |
1146 |
{ |
7699acd13 epoll cleanups: e... |
1147 |
int pwake = 0; |
7699acd13 epoll cleanups: e... |
1148 1149 |
struct epitem *epi = ep_item_from_wait(wait); struct eventpoll *ep = epi->ep; |
3ad6f93e9 annotate poll-rel... |
1150 |
__poll_t pollflags = key_to_poll(key); |
a218cc491 epoll: use rwlock... |
1151 |
unsigned long flags; |
df0108c5d epoll: add EPOLLE... |
1152 |
int ewake = 0; |
1da177e4c Linux-2.6.12-rc2 |
1153 |
|
a218cc491 epoll: use rwlock... |
1154 |
read_lock_irqsave(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1155 |
|
bf3b9f637 epoll: Add busy p... |
1156 |
ep_set_busy_poll_napi_id(epi); |
7699acd13 epoll cleanups: e... |
1157 1158 1159 1160 1161 1162 1163 |
/* * 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 ... |
1164 1165 1166 |
goto out_unlock; /* |
2dfa4eeab epoll keyed wakeu... |
1167 1168 1169 1170 1171 |
* 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... |
1172 |
if (pollflags && !(pollflags & epi->event.events)) |
2dfa4eeab epoll keyed wakeu... |
1173 1174 1175 |
goto out_unlock; /* |
bf6a41db7 fs/eventpoll.c: f... |
1176 |
* If we are transferring events to userspace, we can hold no locks |
d47de16c7 fix epoll single ... |
1177 |
* (because we're accessing user memory, and because of linux f_op->poll() |
bf6a41db7 fs/eventpoll.c: f... |
1178 |
* semantics). All the events that happen during that period of time are |
d47de16c7 fix epoll single ... |
1179 1180 |
* chained in ep->ovflist and requeued later on. */ |
c5a282e96 fs/epoll: reduce ... |
1181 |
if (READ_ONCE(ep->ovflist) != EP_UNACTIVE_PTR) { |
0c54a6a44 eventpoll: fix mi... |
1182 1183 1184 1185 1186 |
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... |
1187 |
ep_pm_stay_awake_rcu(epi); |
4d7e30d98 epoll: Add a flag... |
1188 |
} |
7699acd13 epoll cleanups: e... |
1189 |
|
7699acd13 epoll cleanups: e... |
1190 1191 1192 1193 |
/* * Wake up ( if active ) both the eventpoll wait list and the ->poll() * wait list. */ |
df0108c5d epoll: add EPOLLE... |
1194 |
if (waitqueue_active(&ep->wq)) { |
b6a515c8a epoll: restrict E... |
1195 |
if ((epi->event.events & EPOLLEXCLUSIVE) && |
3ad6f93e9 annotate poll-rel... |
1196 1197 |
!(pollflags & POLLFREE)) { switch (pollflags & EPOLLINOUT_BITS) { |
a9a08845e vfs: do bulk POLL... |
1198 1199 |
case EPOLLIN: if (epi->event.events & EPOLLIN) |
b6a515c8a epoll: restrict E... |
1200 1201 |
ewake = 1; break; |
a9a08845e vfs: do bulk POLL... |
1202 1203 |
case EPOLLOUT: if (epi->event.events & EPOLLOUT) |
b6a515c8a epoll: restrict E... |
1204 1205 1206 1207 1208 1209 1210 |
ewake = 1; break; case 0: ewake = 1; break; } } |
a218cc491 epoll: use rwlock... |
1211 |
wake_up(&ep->wq); |
df0108c5d epoll: add EPOLLE... |
1212 |
} |
7699acd13 epoll cleanups: e... |
1213 1214 |
if (waitqueue_active(&ep->poll_wait)) pwake++; |
d47de16c7 fix epoll single ... |
1215 |
out_unlock: |
a218cc491 epoll: use rwlock... |
1216 |
read_unlock_irqrestore(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1217 |
|
7699acd13 epoll cleanups: e... |
1218 1219 |
/* We have to call this outside the lock */ if (pwake) |
efcdd350d fs/epoll: make ne... |
1220 |
ep_poll_safewake(ep, epi); |
7699acd13 epoll cleanups: e... |
1221 |
|
138e4ad67 epoll: fix race b... |
1222 1223 |
if (!(epi->event.events & EPOLLEXCLUSIVE)) ewake = 1; |
3ad6f93e9 annotate poll-rel... |
1224 |
if (pollflags & POLLFREE) { |
138e4ad67 epoll: fix race b... |
1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 |
/* * 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... |
1239 |
|
138e4ad67 epoll: fix race b... |
1240 |
return ewake; |
7699acd13 epoll cleanups: e... |
1241 |
} |
1da177e4c Linux-2.6.12-rc2 |
1242 1243 1244 1245 1246 1247 1248 1249 |
/* * 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) { |
b030a4dd6 [PATCH] Remove ev... |
1250 |
struct epitem *epi = ep_item_from_epqueue(pt); |
1da177e4c Linux-2.6.12-rc2 |
1251 |
struct eppoll_entry *pwq; |
e94b17660 [PATCH] slab: rem... |
1252 |
if (epi->nwait >= 0 && (pwq = kmem_cache_alloc(pwq_cache, GFP_KERNEL))) { |
1da177e4c Linux-2.6.12-rc2 |
1253 1254 1255 |
init_waitqueue_func_entry(&pwq->wait, ep_poll_callback); pwq->whead = whead; pwq->base = epi; |
df0108c5d epoll: add EPOLLE... |
1256 1257 1258 1259 |
if (epi->event.events & EPOLLEXCLUSIVE) add_wait_queue_exclusive(whead, &pwq->wait); else add_wait_queue(whead, &pwq->wait); |
1da177e4c Linux-2.6.12-rc2 |
1260 1261 |
list_add_tail(&pwq->llink, &epi->pwqlist); epi->nwait++; |
296e236e9 epoll: fix epoll'... |
1262 |
} else { |
1da177e4c Linux-2.6.12-rc2 |
1263 1264 |
/* We have to signal that an error occurred */ epi->nwait = -1; |
296e236e9 epoll: fix epoll'... |
1265 |
} |
1da177e4c Linux-2.6.12-rc2 |
1266 |
} |
1da177e4c Linux-2.6.12-rc2 |
1267 1268 1269 |
static void ep_rbtree_insert(struct eventpoll *ep, struct epitem *epi) { int kcmp; |
b2ac2ea62 fs/epoll: use fas... |
1270 |
struct rb_node **p = &ep->rbr.rb_root.rb_node, *parent = NULL; |
1da177e4c Linux-2.6.12-rc2 |
1271 |
struct epitem *epic; |
b2ac2ea62 fs/epoll: use fas... |
1272 |
bool leftmost = true; |
1da177e4c Linux-2.6.12-rc2 |
1273 1274 1275 1276 |
while (*p) { parent = *p; epic = rb_entry(parent, struct epitem, rbn); |
b030a4dd6 [PATCH] Remove ev... |
1277 |
kcmp = ep_cmp_ffd(&epi->ffd, &epic->ffd); |
b2ac2ea62 fs/epoll: use fas... |
1278 |
if (kcmp > 0) { |
1da177e4c Linux-2.6.12-rc2 |
1279 |
p = &parent->rb_right; |
b2ac2ea62 fs/epoll: use fas... |
1280 1281 |
leftmost = false; } else |
1da177e4c Linux-2.6.12-rc2 |
1282 1283 1284 |
p = &parent->rb_left; } rb_link_node(&epi->rbn, parent, p); |
b2ac2ea62 fs/epoll: use fas... |
1285 |
rb_insert_color_cached(&epi->rbn, &ep->rbr, leftmost); |
1da177e4c Linux-2.6.12-rc2 |
1286 |
} |
a80a6b85b revert "epoll: su... |
1287 |
|
28d82dc1c epoll: limit paths |
1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 |
#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... |
1305 1306 1307 |
/* Allow an arbitrary number of depth 1 paths */ if (nests == 0) return 0; |
28d82dc1c epoll: limit paths |
1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 |
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; } static int reverse_path_check_proc(void *priv, void *cookie, int call_nests) { int error = 0; struct file *file = priv; struct file *child_file; struct epitem *epi; |
ae10b2b4e epoll: optimize E... |
1327 1328 1329 |
/* CTL_DEL can remove links here, but that can't increase our count */ rcu_read_lock(); list_for_each_entry_rcu(epi, &file->f_ep_links, fllink) { |
28d82dc1c epoll: limit paths |
1330 1331 1332 1333 1334 1335 1336 1337 1338 |
child_file = epi->ep->file; if (is_file_epoll(child_file)) { if (list_empty(&child_file->f_ep_links)) { if (path_count_inc(call_nests)) { error = -1; break; } } else { error = ep_call_nested(&poll_loop_ncalls, |
28d82dc1c epoll: limit paths |
1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 |
reverse_path_check_proc, child_file, child_file, current); } if (error != 0) break; } else { printk(KERN_ERR "reverse_path_check_proc: " "file is not an ep! "); } } |
ae10b2b4e epoll: optimize E... |
1351 |
rcu_read_unlock(); |
28d82dc1c epoll: limit paths |
1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 |
return error; } /** * reverse_path_check - The tfile_check_list is list of file *, which have * 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. * * Returns: Returns zero if the proposed links don't create too many paths, * -1 otherwise. */ static int reverse_path_check(void) { |
28d82dc1c epoll: limit paths |
1367 1368 1369 1370 1371 |
int error = 0; struct file *current_file; /* let's call this for all tfiles */ list_for_each_entry(current_file, &tfile_check_list, f_tfile_llink) { |
28d82dc1c epoll: limit paths |
1372 |
path_count_init(); |
74bdc1298 fs/epoll: remove ... |
1373 |
error = ep_call_nested(&poll_loop_ncalls, |
28d82dc1c epoll: limit paths |
1374 1375 1376 1377 1378 1379 1380 |
reverse_path_check_proc, current_file, current_file, current); if (error) break; } return error; } |
4d7e30d98 epoll: Add a flag... |
1381 1382 |
static int ep_create_wakeup_source(struct epitem *epi) { |
3701cb59d ep_create_wakeup_... |
1383 |
struct name_snapshot n; |
eea1d5859 epoll: use RCU to... |
1384 |
struct wakeup_source *ws; |
4d7e30d98 epoll: Add a flag... |
1385 1386 |
if (!epi->ep->ws) { |
c8377adfa PM / wakeup: Show... |
1387 |
epi->ep->ws = wakeup_source_register(NULL, "eventpoll"); |
4d7e30d98 epoll: Add a flag... |
1388 1389 1390 |
if (!epi->ep->ws) return -ENOMEM; } |
3701cb59d ep_create_wakeup_... |
1391 1392 1393 |
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... |
1394 1395 |
if (!ws) |
4d7e30d98 epoll: Add a flag... |
1396 |
return -ENOMEM; |
eea1d5859 epoll: use RCU to... |
1397 |
rcu_assign_pointer(epi->ws, ws); |
4d7e30d98 epoll: Add a flag... |
1398 1399 1400 |
return 0; } |
eea1d5859 epoll: use RCU to... |
1401 1402 |
/* 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... |
1403 |
{ |
eea1d5859 epoll: use RCU to... |
1404 |
struct wakeup_source *ws = ep_wakeup_source(epi); |
d6d67e723 epoll: cleanup: u... |
1405 |
RCU_INIT_POINTER(epi->ws, NULL); |
eea1d5859 epoll: use RCU to... |
1406 1407 1408 1409 1410 1411 1412 1413 |
/* * 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... |
1414 |
} |
c7ea76302 epoll locks chang... |
1415 1416 1417 |
/* * Must be called with "mtx" held. */ |
bec1a502d eventpoll: consti... |
1418 |
static int ep_insert(struct eventpoll *ep, const struct epoll_event *event, |
67347fe4e epoll: do not tak... |
1419 |
struct file *tfile, int fd, int full_check) |
1da177e4c Linux-2.6.12-rc2 |
1420 |
{ |
d85e2aa2e annotate ep_scan_... |
1421 1422 |
int error, pwake = 0; __poll_t revents; |
52bd19f76 epoll: convert ma... |
1423 |
long user_watches; |
1da177e4c Linux-2.6.12-rc2 |
1424 1425 |
struct epitem *epi; struct ep_pqueue epq; |
92e641784 s/epoll: robustif... |
1426 |
lockdep_assert_irqs_enabled(); |
52bd19f76 epoll: convert ma... |
1427 1428 |
user_watches = atomic_long_read(&ep->user->epoll_watches); if (unlikely(user_watches >= max_user_watches)) |
7ef9964e6 epoll: introduce ... |
1429 |
return -ENOSPC; |
e94b17660 [PATCH] slab: rem... |
1430 |
if (!(epi = kmem_cache_alloc(epi_cache, GFP_KERNEL))) |
7ef9964e6 epoll: introduce ... |
1431 |
return -ENOMEM; |
1da177e4c Linux-2.6.12-rc2 |
1432 1433 |
/* Item initialization follow here ... */ |
1da177e4c Linux-2.6.12-rc2 |
1434 1435 |
INIT_LIST_HEAD(&epi->rdllink); INIT_LIST_HEAD(&epi->fllink); |
1da177e4c Linux-2.6.12-rc2 |
1436 1437 |
INIT_LIST_HEAD(&epi->pwqlist); epi->ep = ep; |
b030a4dd6 [PATCH] Remove ev... |
1438 |
ep_set_ffd(&epi->ffd, tfile, fd); |
1da177e4c Linux-2.6.12-rc2 |
1439 |
epi->event = *event; |
1da177e4c Linux-2.6.12-rc2 |
1440 |
epi->nwait = 0; |
d47de16c7 fix epoll single ... |
1441 |
epi->next = EP_UNACTIVE_PTR; |
4d7e30d98 epoll: Add a flag... |
1442 1443 1444 1445 1446 |
if (epi->event.events & EPOLLWAKEUP) { error = ep_create_wakeup_source(epi); if (error) goto error_create_wakeup_source; } else { |
eea1d5859 epoll: use RCU to... |
1447 |
RCU_INIT_POINTER(epi->ws, NULL); |
4d7e30d98 epoll: Add a flag... |
1448 |
} |
1da177e4c Linux-2.6.12-rc2 |
1449 |
|
f8d4f44df epoll: do not ins... |
1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 |
/* Add the current item to the list of active epoll hook for this file */ spin_lock(&tfile->f_lock); list_add_tail_rcu(&epi->fllink, &tfile->f_ep_links); spin_unlock(&tfile->f_lock); /* * 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); /* now check if we've created too many backpaths */ error = -EINVAL; if (full_check && reverse_path_check()) goto error_remove_epi; |
1da177e4c Linux-2.6.12-rc2 |
1465 1466 1467 1468 1469 1470 1471 |
/* 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... |
1472 1473 1474 |
* 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 |
1475 |
*/ |
37b5e5212 epoll: remove ep_... |
1476 |
revents = ep_item_poll(epi, &epq.pt, 1); |
1da177e4c Linux-2.6.12-rc2 |
1477 1478 1479 1480 1481 1482 |
/* * 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. */ |
7ef9964e6 epoll: introduce ... |
1483 |
error = -ENOMEM; |
1da177e4c Linux-2.6.12-rc2 |
1484 |
if (epi->nwait < 0) |
7699acd13 epoll cleanups: e... |
1485 |
goto error_unregister; |
1da177e4c Linux-2.6.12-rc2 |
1486 |
|
c7ea76302 epoll locks chang... |
1487 |
/* We have to drop the new item inside our item list to keep track of it */ |
a218cc491 epoll: use rwlock... |
1488 |
write_lock_irq(&ep->lock); |
c7ea76302 epoll locks chang... |
1489 |
|
bf3b9f637 epoll: Add busy p... |
1490 1491 |
/* record NAPI ID of new item if present */ ep_set_busy_poll_napi_id(epi); |
1da177e4c Linux-2.6.12-rc2 |
1492 |
/* If the file is already "ready" we drop it inside the ready list */ |
992991c03 fs/eventpoll.c: s... |
1493 |
if (revents && !ep_is_linked(epi)) { |
1da177e4c Linux-2.6.12-rc2 |
1494 |
list_add_tail(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
1495 |
ep_pm_stay_awake(epi); |
1da177e4c Linux-2.6.12-rc2 |
1496 1497 1498 |
/* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) |
a218cc491 epoll: use rwlock... |
1499 |
wake_up(&ep->wq); |
1da177e4c Linux-2.6.12-rc2 |
1500 1501 1502 |
if (waitqueue_active(&ep->poll_wait)) pwake++; } |
a218cc491 epoll: use rwlock... |
1503 |
write_unlock_irq(&ep->lock); |
1da177e4c Linux-2.6.12-rc2 |
1504 |
|
52bd19f76 epoll: convert ma... |
1505 |
atomic_long_inc(&ep->user->epoll_watches); |
7ef9964e6 epoll: introduce ... |
1506 |
|
1da177e4c Linux-2.6.12-rc2 |
1507 1508 |
/* We have to call this outside the lock */ if (pwake) |
efcdd350d fs/epoll: make ne... |
1509 |
ep_poll_safewake(ep, NULL); |
1da177e4c Linux-2.6.12-rc2 |
1510 |
|
1da177e4c Linux-2.6.12-rc2 |
1511 |
return 0; |
f8d4f44df epoll: do not ins... |
1512 1513 |
error_unregister: ep_unregister_pollwait(ep, epi); |
28d82dc1c epoll: limit paths |
1514 1515 |
error_remove_epi: spin_lock(&tfile->f_lock); |
ae10b2b4e epoll: optimize E... |
1516 |
list_del_rcu(&epi->fllink); |
28d82dc1c epoll: limit paths |
1517 |
spin_unlock(&tfile->f_lock); |
b2ac2ea62 fs/epoll: use fas... |
1518 |
rb_erase_cached(&epi->rbn, &ep->rbr); |
28d82dc1c epoll: limit paths |
1519 |
|
1da177e4c Linux-2.6.12-rc2 |
1520 1521 |
/* * We need to do this because an event could have been arrived on some |
67647d0fb epoll: fix some c... |
1522 1523 1524 |
* allocated wait queue. Note that we don't care about the ep->ovflist * list, since that is used/cleaned only inside a section bound by "mtx". * And ep_insert() is called with "mtx" held. |
1da177e4c Linux-2.6.12-rc2 |
1525 |
*/ |
a218cc491 epoll: use rwlock... |
1526 |
write_lock_irq(&ep->lock); |
992991c03 fs/eventpoll.c: s... |
1527 |
if (ep_is_linked(epi)) |
6192bd536 epoll: optimizati... |
1528 |
list_del_init(&epi->rdllink); |
a218cc491 epoll: use rwlock... |
1529 |
write_unlock_irq(&ep->lock); |
1da177e4c Linux-2.6.12-rc2 |
1530 |
|
eea1d5859 epoll: use RCU to... |
1531 |
wakeup_source_unregister(ep_wakeup_source(epi)); |
4d7e30d98 epoll: Add a flag... |
1532 1533 |
error_create_wakeup_source: |
b030a4dd6 [PATCH] Remove ev... |
1534 |
kmem_cache_free(epi_cache, epi); |
7ef9964e6 epoll: introduce ... |
1535 |
|
1da177e4c Linux-2.6.12-rc2 |
1536 1537 |
return error; } |
1da177e4c Linux-2.6.12-rc2 |
1538 1539 |
/* * Modify the interest event mask by dropping an event if the new mask |
c7ea76302 epoll locks chang... |
1540 |
* has a match in the current file status. Must be called with "mtx" held. |
1da177e4c Linux-2.6.12-rc2 |
1541 |
*/ |
bec1a502d eventpoll: consti... |
1542 1543 |
static int ep_modify(struct eventpoll *ep, struct epitem *epi, const struct epoll_event *event) |
1da177e4c Linux-2.6.12-rc2 |
1544 1545 |
{ int pwake = 0; |
626cf2366 poll: add poll_re... |
1546 |
poll_table pt; |
92e641784 s/epoll: robustif... |
1547 |
lockdep_assert_irqs_enabled(); |
626cf2366 poll: add poll_re... |
1548 |
init_poll_funcptr(&pt, NULL); |
1da177e4c Linux-2.6.12-rc2 |
1549 1550 |
/* |
e057e15ff epoll: clean up e... |
1551 1552 1553 |
* 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 |
1554 |
*/ |
128dd1759 epoll: prevent mi... |
1555 |
epi->event.events = event->events; /* need barrier below */ |
e057e15ff epoll: clean up e... |
1556 |
epi->event.data = event->data; /* protected by mtx */ |
4d7e30d98 epoll: Add a flag... |
1557 |
if (epi->event.events & EPOLLWAKEUP) { |
eea1d5859 epoll: use RCU to... |
1558 |
if (!ep_has_wakeup_source(epi)) |
4d7e30d98 epoll: Add a flag... |
1559 |
ep_create_wakeup_source(epi); |
eea1d5859 epoll: use RCU to... |
1560 |
} else if (ep_has_wakeup_source(epi)) { |
4d7e30d98 epoll: Add a flag... |
1561 1562 |
ep_destroy_wakeup_source(epi); } |
1da177e4c Linux-2.6.12-rc2 |
1563 1564 |
/* |
128dd1759 epoll: prevent mi... |
1565 1566 1567 1568 1569 |
* 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... |
1570 |
* We need this because we did not take ep->lock while |
128dd1759 epoll: prevent mi... |
1571 |
* changing epi above (but ep_poll_callback does take |
a218cc491 epoll: use rwlock... |
1572 |
* ep->lock). |
128dd1759 epoll: prevent mi... |
1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 |
* * 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 |
1585 1586 |
* 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... |
1587 |
* If the item is "hot" and it is not registered inside the ready |
67647d0fb epoll: fix some c... |
1588 |
* list, push it inside. |
1da177e4c Linux-2.6.12-rc2 |
1589 |
*/ |
69112736e eventpoll: no nee... |
1590 |
if (ep_item_poll(epi, &pt, 1)) { |
a218cc491 epoll: use rwlock... |
1591 |
write_lock_irq(&ep->lock); |
992991c03 fs/eventpoll.c: s... |
1592 |
if (!ep_is_linked(epi)) { |
c7ea76302 epoll locks chang... |
1593 |
list_add_tail(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
1594 |
ep_pm_stay_awake(epi); |
c7ea76302 epoll locks chang... |
1595 1596 1597 |
/* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) |
a218cc491 epoll: use rwlock... |
1598 |
wake_up(&ep->wq); |
c7ea76302 epoll locks chang... |
1599 1600 |
if (waitqueue_active(&ep->poll_wait)) pwake++; |
7699acd13 epoll cleanups: e... |
1601 |
} |
a218cc491 epoll: use rwlock... |
1602 |
write_unlock_irq(&ep->lock); |
7699acd13 epoll cleanups: e... |
1603 |
} |
1da177e4c Linux-2.6.12-rc2 |
1604 |
|
7699acd13 epoll cleanups: e... |
1605 1606 |
/* We have to call this outside the lock */ if (pwake) |
efcdd350d fs/epoll: make ne... |
1607 |
ep_poll_safewake(ep, NULL); |
1da177e4c Linux-2.6.12-rc2 |
1608 |
|
7699acd13 epoll cleanups: e... |
1609 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
1610 |
} |
d85e2aa2e annotate ep_scan_... |
1611 |
static __poll_t ep_send_events_proc(struct eventpoll *ep, struct list_head *head, |
296e236e9 epoll: fix epoll'... |
1612 |
void *priv) |
1da177e4c Linux-2.6.12-rc2 |
1613 |
{ |
5071f97ec epoll: fix epoll'... |
1614 |
struct ep_send_events_data *esed = priv; |
d85e2aa2e annotate ep_scan_... |
1615 |
__poll_t revents; |
4e0982a00 fs/epoll: simplif... |
1616 1617 |
struct epitem *epi, *tmp; struct epoll_event __user *uevent = esed->events; |
eea1d5859 epoll: use RCU to... |
1618 |
struct wakeup_source *ws; |
626cf2366 poll: add poll_re... |
1619 1620 1621 |
poll_table pt; init_poll_funcptr(&pt, NULL); |
4e0982a00 fs/epoll: simplif... |
1622 |
esed->res = 0; |
1da177e4c Linux-2.6.12-rc2 |
1623 |
|
296e236e9 epoll: fix epoll'... |
1624 |
/* |
5071f97ec epoll: fix epoll'... |
1625 1626 1627 |
* We can loop without lock because we are passed a task private list. * Items cannot vanish during the loop because ep_scan_ready_list() is * holding "mtx" during this call. |
296e236e9 epoll: fix epoll'... |
1628 |
*/ |
21877e1a5 fs/epoll: robusti... |
1629 |
lockdep_assert_held(&ep->mtx); |
4e0982a00 fs/epoll: simplif... |
1630 1631 1632 |
list_for_each_entry_safe(epi, tmp, head, rdllink) { if (esed->res >= esed->maxevents) break; |
d47de16c7 fix epoll single ... |
1633 |
|
4d7e30d98 epoll: Add a flag... |
1634 1635 1636 1637 1638 1639 1640 1641 1642 |
/* * 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... |
1643 1644 1645 1646 1647 1648 |
ws = ep_wakeup_source(epi); if (ws) { if (ws->active) __pm_stay_awake(ep->ws); __pm_relax(ws); } |
d47de16c7 fix epoll single ... |
1649 |
list_del_init(&epi->rdllink); |
1da177e4c Linux-2.6.12-rc2 |
1650 |
|
296e236e9 epoll: fix epoll'... |
1651 |
/* |
5071f97ec epoll: fix epoll'... |
1652 1653 |
* If the event mask intersect the caller-requested one, * deliver the event to userspace. Again, ep_scan_ready_list() |
4e0982a00 fs/epoll: simplif... |
1654 |
* is holding ep->mtx, so no operations coming from userspace |
5071f97ec epoll: fix epoll'... |
1655 |
* can change the item. |
296e236e9 epoll: fix epoll'... |
1656 |
*/ |
4e0982a00 fs/epoll: simplif... |
1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 |
revents = ep_item_poll(epi, &pt, 1); if (!revents) continue; if (__put_user(revents, &uevent->events) || __put_user(epi->event.data, &uevent->data)) { list_add(&epi->rdllink, head); ep_pm_stay_awake(epi); if (!esed->res) esed->res = -EFAULT; return 0; } esed->res++; uevent++; 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'... |
1687 1688 |
} } |
5071f97ec epoll: fix epoll'... |
1689 |
|
d7ebbe46f ep_send_events_pr... |
1690 |
return 0; |
5071f97ec epoll: fix epoll'... |
1691 |
} |
d47de16c7 fix epoll single ... |
1692 |
|
296e236e9 epoll: fix epoll'... |
1693 1694 |
static int ep_send_events(struct eventpoll *ep, struct epoll_event __user *events, int maxevents) |
5071f97ec epoll: fix epoll'... |
1695 1696 |
{ struct ep_send_events_data esed; |
1da177e4c Linux-2.6.12-rc2 |
1697 |
|
5071f97ec epoll: fix epoll'... |
1698 1699 |
esed.maxevents = maxevents; esed.events = events; |
6192bd536 epoll: optimizati... |
1700 |
|
d7ebbe46f ep_send_events_pr... |
1701 1702 |
ep_scan_ready_list(ep, ep_send_events_proc, &esed, 0, false); return esed.res; |
1da177e4c Linux-2.6.12-rc2 |
1703 |
} |
766b9f928 fs: poll/select/r... |
1704 |
static inline struct timespec64 ep_set_mstimeout(long ms) |
0781b909b epoll: epoll_wait... |
1705 |
{ |
766b9f928 fs: poll/select/r... |
1706 |
struct timespec64 now, ts = { |
0781b909b epoll: epoll_wait... |
1707 1708 1709 |
.tv_sec = ms / MSEC_PER_SEC, .tv_nsec = NSEC_PER_MSEC * (ms % MSEC_PER_SEC), }; |
766b9f928 fs: poll/select/r... |
1710 1711 |
ktime_get_ts64(&now); return timespec64_add_safe(now, ts); |
0781b909b epoll: epoll_wait... |
1712 |
} |
f4d93ad74 epoll: fix compil... |
1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 |
/** * ep_poll - Retrieves ready events, and delivers them to the caller supplied * 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 * milliseconds. If the @timeout is zero, the function will not block, * while if the @timeout is less than zero, the function will block * until at least one event has been retrieved (or an error * occurred). * * Returns: Returns the number of ready events which have been fetched, or an * error code, in case of error. */ |
1da177e4c Linux-2.6.12-rc2 |
1730 1731 1732 |
static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events, int maxevents, long timeout) { |
f4d93ad74 epoll: fix compil... |
1733 |
int res = 0, eavail, timed_out = 0; |
da8b44d5a timer: convert ti... |
1734 |
u64 slack = 0; |
ac6424b98 sched/wait: Renam... |
1735 |
wait_queue_entry_t wait; |
95aac7b1c epoll: make epoll... |
1736 |
ktime_t expires, *to = NULL; |
679abf381 fs/eventpoll.c: l... |
1737 |
lockdep_assert_irqs_enabled(); |
95aac7b1c epoll: make epoll... |
1738 |
if (timeout > 0) { |
766b9f928 fs: poll/select/r... |
1739 |
struct timespec64 end_time = ep_set_mstimeout(timeout); |
0781b909b epoll: epoll_wait... |
1740 |
|
95aac7b1c epoll: make epoll... |
1741 1742 |
slack = select_estimate_accuracy(&end_time); to = &expires; |
766b9f928 fs: poll/select/r... |
1743 |
*to = timespec64_to_ktime(end_time); |
95aac7b1c epoll: make epoll... |
1744 |
} else if (timeout == 0) { |
f4d93ad74 epoll: fix compil... |
1745 1746 |
/* * Avoid the unnecessary trip to the wait queue loop, if the |
c5a282e96 fs/epoll: reduce ... |
1747 1748 1749 1750 |
* caller specified a non blocking operation. We still need * lock because we could race and not see an epi being added * to the ready list while in irq callback. Thus incorrectly * returning 0 back to userspace. |
f4d93ad74 epoll: fix compil... |
1751 |
*/ |
95aac7b1c epoll: make epoll... |
1752 |
timed_out = 1; |
c5a282e96 fs/epoll: reduce ... |
1753 |
|
a218cc491 epoll: use rwlock... |
1754 |
write_lock_irq(&ep->lock); |
c5a282e96 fs/epoll: reduce ... |
1755 |
eavail = ep_events_available(ep); |
a218cc491 epoll: use rwlock... |
1756 |
write_unlock_irq(&ep->lock); |
c5a282e96 fs/epoll: reduce ... |
1757 |
|
35cff1a6e fs/epoll: rename ... |
1758 |
goto send_events; |
95aac7b1c epoll: make epoll... |
1759 |
} |
1da177e4c Linux-2.6.12-rc2 |
1760 |
|
f4d93ad74 epoll: fix compil... |
1761 |
fetch_events: |
bf3b9f637 epoll: Add busy p... |
1762 1763 1764 |
if (!ep_events_available(ep)) ep_busy_loop(ep, timed_out); |
c5a282e96 fs/epoll: reduce ... |
1765 1766 |
eavail = ep_events_available(ep); if (eavail) |
35cff1a6e fs/epoll: rename ... |
1767 |
goto send_events; |
1da177e4c Linux-2.6.12-rc2 |
1768 |
|
c5a282e96 fs/epoll: reduce ... |
1769 1770 1771 1772 1773 1774 |
/* * 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. */ ep_reset_busy_poll_napi_id(ep); |
bf3b9f637 epoll: Add busy p... |
1775 |
|
412895f03 epoll: atomically... |
1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 |
do { /* * 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. */ init_wait(&wait); |
1da177e4c Linux-2.6.12-rc2 |
1789 |
|
65759097d epoll: call final... |
1790 |
write_lock_irq(&ep->lock); |
1da177e4c Linux-2.6.12-rc2 |
1791 |
/* |
65759097d epoll: call final... |
1792 1793 1794 |
* 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... |
1795 |
*/ |
65759097d epoll: call final... |
1796 |
__set_current_state(TASK_INTERRUPTIBLE); |
bf3b9f637 epoll: Add busy p... |
1797 |
/* |
65759097d epoll: call final... |
1798 1799 1800 1801 1802 |
* 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 |
1803 |
*/ |
65759097d epoll: call final... |
1804 1805 1806 1807 1808 1809 |
eavail = ep_events_available(ep); if (!eavail) { if (signal_pending(current)) res = -EINTR; else __add_wait_queue_exclusive(&ep->wq, &wait); |
c5a282e96 fs/epoll: reduce ... |
1810 |
} |
65759097d epoll: call final... |
1811 |
write_unlock_irq(&ep->lock); |
95aac7b1c epoll: make epoll... |
1812 |
|
1afb979cd epoll: check for ... |
1813 1814 1815 |
if (!eavail && !res) timed_out = !schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS); |
1da177e4c Linux-2.6.12-rc2 |
1816 |
|
1afb979cd epoll: check for ... |
1817 1818 1819 1820 1821 |
/* * 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... |
1822 |
eavail = 1; |
412895f03 epoll: atomically... |
1823 |
} while (0); |
1da177e4c Linux-2.6.12-rc2 |
1824 |
|
c5a282e96 fs/epoll: reduce ... |
1825 |
__set_current_state(TASK_RUNNING); |
1da177e4c Linux-2.6.12-rc2 |
1826 |
|
412895f03 epoll: atomically... |
1827 1828 |
if (!list_empty_careful(&wait.entry)) { write_lock_irq(&ep->lock); |
1afb979cd epoll: check for ... |
1829 1830 1831 1832 1833 1834 1835 1836 |
/* * 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); |
412895f03 epoll: atomically... |
1837 1838 1839 |
__remove_wait_queue(&ep->wq, &wait); write_unlock_irq(&ep->lock); } |
35cff1a6e fs/epoll: rename ... |
1840 |
send_events: |
65759097d epoll: call final... |
1841 1842 1843 1844 1845 1846 1847 1848 1849 |
if (fatal_signal_pending(current)) { /* * 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. */ res = -EINTR; } |
1da177e4c Linux-2.6.12-rc2 |
1850 1851 1852 1853 1854 1855 |
/* * 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. */ if (!res && eavail && |
95aac7b1c epoll: make epoll... |
1856 |
!(res = ep_send_events(ep, events, maxevents)) && !timed_out) |
f4d93ad74 epoll: fix compil... |
1857 |
goto fetch_events; |
1da177e4c Linux-2.6.12-rc2 |
1858 1859 1860 |
return res; } |
22bacca48 epoll: prevent cr... |
1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 |
/** * ep_loop_check_proc - Callback function to be passed to the @ep_call_nested() * API, to verify that adding an epoll file inside another * epoll structure, does not violate the constraints, in * terms of closed loops, or too deep chains (which can * result in excessive stack usage). * * @priv: Pointer to the epoll file to be currently checked. * @cookie: Original cookie for this call. This is the top-of-the-chain epoll * data structure pointer. * @call_nests: Current dept of the @ep_call_nested() call stack. * * Returns: Returns zero if adding the epoll @file inside current epoll * structure @ep does not violate the constraints, or -1 otherwise. */ static int ep_loop_check_proc(void *priv, void *cookie, int call_nests) { int error = 0; struct file *file = priv; struct eventpoll *ep = file->private_data; |
28d82dc1c epoll: limit paths |
1881 |
struct eventpoll *ep_tovisit; |
22bacca48 epoll: prevent cr... |
1882 1883 |
struct rb_node *rbp; struct epitem *epi; |
d8805e633 epoll: fix spurio... |
1884 |
mutex_lock_nested(&ep->mtx, call_nests + 1); |
18306c404 epoll: replace ->... |
1885 |
ep->gen = loop_check_gen; |
b2ac2ea62 fs/epoll: use fas... |
1886 |
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
22bacca48 epoll: prevent cr... |
1887 1888 |
epi = rb_entry(rbp, struct epitem, rbn); if (unlikely(is_file_epoll(epi->ffd.file))) { |
28d82dc1c epoll: limit paths |
1889 |
ep_tovisit = epi->ffd.file->private_data; |
18306c404 epoll: replace ->... |
1890 |
if (ep_tovisit->gen == loop_check_gen) |
28d82dc1c epoll: limit paths |
1891 |
continue; |
74bdc1298 fs/epoll: remove ... |
1892 |
error = ep_call_nested(&poll_loop_ncalls, |
28d82dc1c epoll: limit paths |
1893 1894 |
ep_loop_check_proc, epi->ffd.file, ep_tovisit, current); |
22bacca48 epoll: prevent cr... |
1895 1896 |
if (error != 0) break; |
28d82dc1c epoll: limit paths |
1897 1898 1899 1900 1901 1902 1903 1904 1905 |
} 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(). */ |
a9ed4a656 epoll: Keep a ref... |
1906 |
if (list_empty(&epi->ffd.file->f_tfile_llink)) { |
77f4689de fix regression in... |
1907 1908 1909 |
if (get_file_rcu(epi->ffd.file)) list_add(&epi->ffd.file->f_tfile_llink, &tfile_check_list); |
a9ed4a656 epoll: Keep a ref... |
1910 |
} |
22bacca48 epoll: prevent cr... |
1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 |
} } mutex_unlock(&ep->mtx); return error; } /** * ep_loop_check - Performs a check to verify that adding an epoll file (@file) * another epoll file (represented by @ep) does not create * closed loops or too deep chains. * * @ep: Pointer to the epoll private data structure. * @file: Pointer to the epoll file to be checked. * * Returns: Returns zero if adding the epoll @file inside current epoll * structure @ep does not violate the constraints, or -1 otherwise. */ static int ep_loop_check(struct eventpoll *ep, struct file *file) { |
18306c404 epoll: replace ->... |
1931 |
return ep_call_nested(&poll_loop_ncalls, |
22bacca48 epoll: prevent cr... |
1932 |
ep_loop_check_proc, file, ep, current); |
28d82dc1c epoll: limit paths |
1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 |
} static void clear_tfile_check_list(void) { struct file *file; /* first clear the tfile_check_list */ while (!list_empty(&tfile_check_list)) { file = list_first_entry(&tfile_check_list, struct file, f_tfile_llink); list_del_init(&file->f_tfile_llink); |
a9ed4a656 epoll: Keep a ref... |
1944 |
fput(file); |
28d82dc1c epoll: limit paths |
1945 1946 |
} INIT_LIST_HEAD(&tfile_check_list); |
22bacca48 epoll: prevent cr... |
1947 |
} |
7699acd13 epoll cleanups: e... |
1948 |
/* |
523723bb5 fs/eventpoll.c: f... |
1949 |
* Open an eventpoll file descriptor. |
7699acd13 epoll cleanups: e... |
1950 |
*/ |
791eb22ee fs: add do_epoll_... |
1951 |
static int do_epoll_create(int flags) |
7699acd13 epoll cleanups: e... |
1952 |
{ |
28d82dc1c epoll: limit paths |
1953 |
int error, fd; |
bb57c3edc epoll: remove deb... |
1954 |
struct eventpoll *ep = NULL; |
28d82dc1c epoll: limit paths |
1955 |
struct file *file; |
7699acd13 epoll cleanups: e... |
1956 |
|
e38b36f32 flag parameters: ... |
1957 1958 |
/* Check the EPOLL_* constant for consistency. */ BUILD_BUG_ON(EPOLL_CLOEXEC != O_CLOEXEC); |
296e236e9 epoll: fix epoll'... |
1959 1960 |
if (flags & ~EPOLL_CLOEXEC) return -EINVAL; |
7699acd13 epoll cleanups: e... |
1961 |
/* |
bb57c3edc epoll: remove deb... |
1962 |
* Create the internal data structure ("struct eventpoll"). |
7699acd13 epoll cleanups: e... |
1963 |
*/ |
9fe5ad9c8 flag parameters a... |
1964 |
error = ep_alloc(&ep); |
bb57c3edc epoll: remove deb... |
1965 1966 |
if (error < 0) return error; |
7699acd13 epoll cleanups: e... |
1967 1968 |
/* * Creates all the items needed to setup an eventpoll file. That is, |
2030a42ce [PATCH] sanitize ... |
1969 |
* a file structure and a free file descriptor. |
7699acd13 epoll cleanups: e... |
1970 |
*/ |
28d82dc1c epoll: limit paths |
1971 1972 1973 1974 1975 1976 |
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... |
1977 |
O_RDWR | (flags & O_CLOEXEC)); |
28d82dc1c epoll: limit paths |
1978 1979 1980 1981 |
if (IS_ERR(file)) { error = PTR_ERR(file); goto out_free_fd; } |
28d82dc1c epoll: limit paths |
1982 |
ep->file = file; |
98022748f eventpoll: use-af... |
1983 |
fd_install(fd, file); |
28d82dc1c epoll: limit paths |
1984 1985 1986 1987 1988 1989 |
return fd; out_free_fd: put_unused_fd(fd); out_free_ep: ep_free(ep); |
bb57c3edc epoll: remove deb... |
1990 |
return error; |
7699acd13 epoll cleanups: e... |
1991 |
} |
791eb22ee fs: add do_epoll_... |
1992 1993 1994 1995 |
SYSCALL_DEFINE1(epoll_create1, int, flags) { return do_epoll_create(flags); } |
5a8a82b1d [CVE-2009-0029] S... |
1996 |
SYSCALL_DEFINE1(epoll_create, int, size) |
a0998b50c flag parameters: ... |
1997 |
{ |
bfe3891a5 epoll: fix size c... |
1998 |
if (size <= 0) |
9fe5ad9c8 flag parameters a... |
1999 |
return -EINVAL; |
791eb22ee fs: add do_epoll_... |
2000 |
return do_epoll_create(0); |
a0998b50c flag parameters: ... |
2001 |
} |
39220e8d4 eventpoll: suppor... |
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 |
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... |
2016 2017 |
{ int error; |
67347fe4e epoll: do not tak... |
2018 |
int full_check = 0; |
7e3fb5842 switch epoll_ctl(... |
2019 |
struct fd f, tf; |
7699acd13 epoll cleanups: e... |
2020 2021 |
struct eventpoll *ep; struct epitem *epi; |
67347fe4e epoll: do not tak... |
2022 |
struct eventpoll *tep = NULL; |
7699acd13 epoll cleanups: e... |
2023 |
|
7699acd13 epoll cleanups: e... |
2024 |
error = -EBADF; |
7e3fb5842 switch epoll_ctl(... |
2025 2026 |
f = fdget(epfd); if (!f.file) |
7699acd13 epoll cleanups: e... |
2027 2028 2029 |
goto error_return; /* Get the "struct file *" for the target file */ |
7e3fb5842 switch epoll_ctl(... |
2030 2031 |
tf = fdget(fd); if (!tf.file) |
7699acd13 epoll cleanups: e... |
2032 2033 2034 2035 |
goto error_fput; /* The target file descriptor must support poll */ error = -EPERM; |
9965ed174 fs: add new vfs_p... |
2036 |
if (!file_can_poll(tf.file)) |
7699acd13 epoll cleanups: e... |
2037 |
goto error_tgt_fput; |
4d7e30d98 epoll: Add a flag... |
2038 |
/* Check if EPOLLWAKEUP is allowed */ |
c680e41b3 eventpoll: fix un... |
2039 |
if (ep_op_has_event(op)) |
58e41a44c eventpoll: abstra... |
2040 |
ep_take_care_of_epollwakeup(epds); |
4d7e30d98 epoll: Add a flag... |
2041 |
|
7699acd13 epoll cleanups: e... |
2042 2043 2044 2045 2046 2047 |
/* * 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(... |
2048 |
if (f.file == tf.file || !is_file_epoll(f.file)) |
7699acd13 epoll cleanups: e... |
2049 2050 2051 |
goto error_tgt_fput; /* |
df0108c5d epoll: add EPOLLE... |
2052 2053 2054 2055 |
* 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... |
2056 |
if (ep_op_has_event(op) && (epds->events & EPOLLEXCLUSIVE)) { |
b6a515c8a epoll: restrict E... |
2057 2058 2059 |
if (op == EPOLL_CTL_MOD) goto error_tgt_fput; if (op == EPOLL_CTL_ADD && (is_file_epoll(tf.file) || |
58e41a44c eventpoll: abstra... |
2060 |
(epds->events & ~EPOLLEXCLUSIVE_OK_BITS))) |
b6a515c8a epoll: restrict E... |
2061 2062 |
goto error_tgt_fput; } |
df0108c5d epoll: add EPOLLE... |
2063 2064 |
/* |
7699acd13 epoll cleanups: e... |
2065 2066 2067 |
* At this point it is safe to assume that the "private_data" contains * our own data structure. */ |
7e3fb5842 switch epoll_ctl(... |
2068 |
ep = f.file->private_data; |
7699acd13 epoll cleanups: e... |
2069 |
|
22bacca48 epoll: prevent cr... |
2070 2071 2072 |
/* * When we insert an epoll file descriptor, inside another epoll file * descriptor, there is the change of creating closed loops, which are |
28d82dc1c epoll: limit paths |
2073 2074 2075 2076 |
* 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... |
2077 |
* |
67347fe4e epoll: do not tak... |
2078 2079 2080 2081 2082 2083 |
* 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... |
2084 |
*/ |
39220e8d4 eventpoll: suppor... |
2085 2086 2087 |
error = epoll_mutex_lock(&ep->mtx, 0, nonblock); if (error) goto error_tgt_fput; |
28d82dc1c epoll: limit paths |
2088 |
if (op == EPOLL_CTL_ADD) { |
67347fe4e epoll: do not tak... |
2089 |
if (!list_empty(&f.file->f_ep_links) || |
fe0a916c1 epoll: EPOLL_CTL_... |
2090 |
ep->gen == loop_check_gen || |
67347fe4e epoll: do not tak... |
2091 |
is_file_epoll(tf.file)) { |
67347fe4e epoll: do not tak... |
2092 |
mutex_unlock(&ep->mtx); |
39220e8d4 eventpoll: suppor... |
2093 2094 2095 |
error = epoll_mutex_lock(&epmutex, 0, nonblock); if (error) goto error_tgt_fput; |
18306c404 epoll: replace ->... |
2096 |
loop_check_gen++; |
39220e8d4 eventpoll: suppor... |
2097 |
full_check = 1; |
67347fe4e epoll: do not tak... |
2098 2099 |
if (is_file_epoll(tf.file)) { error = -ELOOP; |
52c479697 do_epoll_ctl(): c... |
2100 |
if (ep_loop_check(ep, tf.file) != 0) |
67347fe4e epoll: do not tak... |
2101 |
goto error_tgt_fput; |
a9ed4a656 epoll: Keep a ref... |
2102 2103 |
} else { get_file(tf.file); |
67347fe4e epoll: do not tak... |
2104 2105 |
list_add(&tf.file->f_tfile_llink, &tfile_check_list); |
a9ed4a656 epoll: Keep a ref... |
2106 |
} |
39220e8d4 eventpoll: suppor... |
2107 |
error = epoll_mutex_lock(&ep->mtx, 0, nonblock); |
52c479697 do_epoll_ctl(): c... |
2108 |
if (error) |
39220e8d4 eventpoll: suppor... |
2109 |
goto error_tgt_fput; |
67347fe4e epoll: do not tak... |
2110 2111 |
if (is_file_epoll(tf.file)) { tep = tf.file->private_data; |
39220e8d4 eventpoll: suppor... |
2112 2113 2114 |
error = epoll_mutex_lock(&tep->mtx, 1, nonblock); if (error) { mutex_unlock(&ep->mtx); |
52c479697 do_epoll_ctl(): c... |
2115 |
goto error_tgt_fput; |
39220e8d4 eventpoll: suppor... |
2116 |
} |
13d518074 epoll: clear the ... |
2117 |
} |
67347fe4e epoll: do not tak... |
2118 2119 |
} } |
7699acd13 epoll cleanups: e... |
2120 |
|
67647d0fb epoll: fix some c... |
2121 2122 2123 2124 2125 |
/* * Try to lookup the file inside our RB tree, Since we grabbed "mtx" * 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(... |
2126 |
epi = ep_find(ep, tf.file, fd); |
7699acd13 epoll cleanups: e... |
2127 2128 2129 2130 2131 |
error = -EINVAL; switch (op) { case EPOLL_CTL_ADD: if (!epi) { |
58e41a44c eventpoll: abstra... |
2132 2133 |
epds->events |= EPOLLERR | EPOLLHUP; error = ep_insert(ep, epds, tf.file, fd, full_check); |
7699acd13 epoll cleanups: e... |
2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 |
} 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... |
2145 |
if (!(epi->event.events & EPOLLEXCLUSIVE)) { |
58e41a44c eventpoll: abstra... |
2146 2147 |
epds->events |= EPOLLERR | EPOLLHUP; error = ep_modify(ep, epi, epds); |
b6a515c8a epoll: restrict E... |
2148 |
} |
7699acd13 epoll cleanups: e... |
2149 2150 2151 2152 |
} else error = -ENOENT; break; } |
67347fe4e epoll: do not tak... |
2153 2154 |
if (tep != NULL) mutex_unlock(&tep->mtx); |
d47de16c7 fix epoll single ... |
2155 |
mutex_unlock(&ep->mtx); |
7699acd13 epoll cleanups: e... |
2156 2157 |
error_tgt_fput: |
52c479697 do_epoll_ctl(): c... |
2158 2159 |
if (full_check) { clear_tfile_check_list(); |
18306c404 epoll: replace ->... |
2160 |
loop_check_gen++; |
22bacca48 epoll: prevent cr... |
2161 |
mutex_unlock(&epmutex); |
52c479697 do_epoll_ctl(): c... |
2162 |
} |
22bacca48 epoll: prevent cr... |
2163 |
|
7e3fb5842 switch epoll_ctl(... |
2164 |
fdput(tf); |
7699acd13 epoll cleanups: e... |
2165 |
error_fput: |
7e3fb5842 switch epoll_ctl(... |
2166 |
fdput(f); |
7699acd13 epoll cleanups: e... |
2167 |
error_return: |
7699acd13 epoll cleanups: e... |
2168 2169 2170 2171 2172 |
return error; } /* |
58e41a44c eventpoll: abstra... |
2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 |
* 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... |
2185 |
return do_epoll_ctl(epfd, op, fd, &epds, false); |
58e41a44c eventpoll: abstra... |
2186 2187 2188 |
} /* |
7699acd13 epoll cleanups: e... |
2189 2190 2191 |
* 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_... |
2192 2193 |
static int do_epoll_wait(int epfd, struct epoll_event __user *events, int maxevents, int timeout) |
7699acd13 epoll cleanups: e... |
2194 |
{ |
2903ff019 switch simple cas... |
2195 2196 |
int error; struct fd f; |
7699acd13 epoll cleanups: e... |
2197 |
struct eventpoll *ep; |
7699acd13 epoll cleanups: e... |
2198 2199 2200 2201 2202 |
/* 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... |
2203 |
if (!access_ok(events, maxevents * sizeof(struct epoll_event))) |
2903ff019 switch simple cas... |
2204 |
return -EFAULT; |
7699acd13 epoll cleanups: e... |
2205 2206 |
/* Get the "struct file *" for the eventpoll file */ |
2903ff019 switch simple cas... |
2207 2208 2209 |
f = fdget(epfd); if (!f.file) return -EBADF; |
7699acd13 epoll cleanups: e... |
2210 2211 2212 2213 2214 2215 |
/* * 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... |
2216 |
if (!is_file_epoll(f.file)) |
7699acd13 epoll cleanups: e... |
2217 2218 2219 2220 2221 2222 |
goto error_fput; /* * At this point it is safe to assume that the "private_data" contains * our own data structure. */ |
2903ff019 switch simple cas... |
2223 |
ep = f.file->private_data; |
7699acd13 epoll cleanups: e... |
2224 2225 2226 2227 2228 |
/* Time to fish for events ... */ error = ep_poll(ep, events, maxevents, timeout); error_fput: |
2903ff019 switch simple cas... |
2229 |
fdput(f); |
7699acd13 epoll cleanups: e... |
2230 2231 |
return error; } |
791eb22ee fs: add do_epoll_... |
2232 2233 2234 2235 2236 |
SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events, int, maxevents, int, timeout) { return do_epoll_wait(epfd, events, maxevents, timeout); } |
7699acd13 epoll cleanups: e... |
2237 2238 2239 2240 |
/* * Implement the event wait interface for the eventpoll file. It is the kernel * part of the user space epoll_pwait(2). */ |
5a8a82b1d [CVE-2009-0029] S... |
2241 2242 2243 |
SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events, int, maxevents, int, timeout, const sigset_t __user *, sigmask, size_t, sigsetsize) |
7699acd13 epoll cleanups: e... |
2244 2245 |
{ int error; |
7699acd13 epoll cleanups: e... |
2246 2247 2248 2249 2250 |
/* * If the caller wants a certain signal mask to be set during the wait, * we apply it here. */ |
b772434be signal: simplify ... |
2251 |
error = set_user_sigmask(sigmask, sigsetsize); |
ded653ccb signal: Add set_u... |
2252 2253 |
if (error) return error; |
7699acd13 epoll cleanups: e... |
2254 |
|
791eb22ee fs: add do_epoll_... |
2255 |
error = do_epoll_wait(epfd, events, maxevents, timeout); |
b772434be signal: simplify ... |
2256 |
restore_saved_sigmask_unless(error == -EINTR); |
7699acd13 epoll cleanups: e... |
2257 2258 2259 |
return error; } |
35280bd4a switch epoll_pwai... |
2260 2261 2262 2263 2264 2265 2266 2267 |
#ifdef CONFIG_COMPAT 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) { long err; |
35280bd4a switch epoll_pwai... |
2268 2269 2270 2271 2272 |
/* * If the caller wants a certain signal mask to be set during the wait, * we apply it here. */ |
b772434be signal: simplify ... |
2273 |
err = set_compat_user_sigmask(sigmask, sigsetsize); |
ded653ccb signal: Add set_u... |
2274 2275 |
if (err) return err; |
35280bd4a switch epoll_pwai... |
2276 |
|
791eb22ee fs: add do_epoll_... |
2277 |
err = do_epoll_wait(epfd, events, maxevents, timeout); |
b772434be signal: simplify ... |
2278 |
restore_saved_sigmask_unless(err == -EINTR); |
35280bd4a switch epoll_pwai... |
2279 2280 2281 2282 |
return err; } #endif |
1da177e4c Linux-2.6.12-rc2 |
2283 2284 |
static int __init eventpoll_init(void) { |
7ef9964e6 epoll: introduce ... |
2285 2286 2287 |
struct sysinfo si; si_meminfo(&si); |
9df04e1f2 epoll: drop max_u... |
2288 2289 2290 2291 |
/* * 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 ... |
2292 |
EP_ITEM_COST; |
52bd19f76 epoll: convert ma... |
2293 |
BUG_ON(max_user_watches < 0); |
1da177e4c Linux-2.6.12-rc2 |
2294 |
|
22bacca48 epoll: prevent cr... |
2295 2296 2297 2298 2299 |
/* * Initialize the structure used to perform epoll file descriptor * inclusion loops checks. */ ep_nested_calls_init(&poll_loop_ncalls); |
39732ca5a epoll: trim epite... |
2300 2301 2302 2303 2304 |
/* * 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 |
2305 2306 |
/* Allocates slab cache used to allocate "struct epitem" items */ epi_cache = kmem_cache_create("eventpoll_epi", sizeof(struct epitem), |
2ae928a94 epoll: account ep... |
2307 |
0, SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL); |
1da177e4c Linux-2.6.12-rc2 |
2308 2309 2310 |
/* Allocates slab cache used to allocate "struct eppoll_entry" */ pwq_cache = kmem_cache_create("eventpoll_pwq", |
2ae928a94 epoll: account ep... |
2311 |
sizeof(struct eppoll_entry), 0, SLAB_PANIC|SLAB_ACCOUNT, NULL); |
1da177e4c Linux-2.6.12-rc2 |
2312 |
|
1da177e4c Linux-2.6.12-rc2 |
2313 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
2314 |
} |
cea692418 epoll cleanups: e... |
2315 |
fs_initcall(eventpoll_init); |