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fs/eventpoll.c
63.9 KB
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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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* * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * Davide Libenzi <davidel@xmailserver.org> * */ |
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#include <linux/init.h> #include <linux/kernel.h> |
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#include <linux/sched/signal.h> |
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#include <linux/fs.h> #include <linux/file.h> #include <linux/signal.h> #include <linux/errno.h> #include <linux/mm.h> #include <linux/slab.h> #include <linux/poll.h> |
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#include <linux/string.h> #include <linux/list.h> #include <linux/hash.h> #include <linux/spinlock.h> #include <linux/syscalls.h> |
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#include <linux/rbtree.h> #include <linux/wait.h> #include <linux/eventpoll.h> #include <linux/mount.h> #include <linux/bitops.h> |
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#include <linux/mutex.h> |
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#include <linux/anon_inodes.h> |
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#include <linux/device.h> |
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#include <linux/uaccess.h> |
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#include <asm/io.h> #include <asm/mman.h> |
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#include <linux/atomic.h> |
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#include <linux/proc_fs.h> #include <linux/seq_file.h> |
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#include <linux/compat.h> |
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#include <linux/rculist.h> |
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#include <net/busy_poll.h> |
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/* * LOCKING: * There are three level of locking required by epoll : * |
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* 1) epmutex (mutex) |
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* 2) ep->mtx (mutex) * 3) ep->lock (spinlock) |
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* * The acquire order is the one listed above, from 1 to 3. * We need a spinlock (ep->lock) because we manipulate objects * 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 * mutex "epmutex" (together with "ep->lock") to have it working, * 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 (POLLIN | POLLOUT) #define EPOLLEXCLUSIVE_OK_BITS (EPOLLINOUT_BITS | POLLERR | POLLHUP | \ 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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/* Protect the access to this structure */ |
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spinlock_t lock; |
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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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/* 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. */ struct epitem *ovflist; |
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/* wakeup_source used when ep_scan_ready_list is running */ struct wakeup_source *ws; |
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/* The user that created the eventpoll descriptor */ struct user_struct *user; |
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struct file *file; /* used to optimize loop detection check */ int visited; struct list_head visited_list_link; |
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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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}; /* 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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/* |
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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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/* Used to check for epoll file descriptor inclusion loops */ static struct nested_calls poll_loop_ncalls; |
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/* Used for safe wake up implementation */ static struct nested_calls poll_safewake_ncalls; /* Used to call file's f_op->poll() under the nested calls boundaries */ static struct nested_calls poll_readywalk_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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/* Visited nodes during ep_loop_check(), so we can unset them when we finish */ static LIST_HEAD(visited_list); /* * 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 zero; static long long_max = LONG_MAX; |
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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 = &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 */ static inline int ep_is_linked(struct list_head *p) { return !list_empty(p); } |
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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; } /* Tells if the epoll_ctl(2) operation needs an event copy from userspace */ |
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static inline int ep_op_has_event(int op) |
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{ |
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return op != EPOLL_CTL_DEL; |
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} |
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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) { return !list_empty(&ep->rdllist) || ep->ovflist != EP_UNACTIVE_PTR; } |
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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); } #endif /* CONFIG_NET_RX_BUSY_POLL */ /* * 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) { #ifdef CONFIG_NET_RX_BUSY_POLL 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); #endif } static inline void ep_reset_busy_poll_napi_id(struct eventpoll *ep) { #ifdef CONFIG_NET_RX_BUSY_POLL if (ep->napi_id) ep->napi_id = 0; #endif } /* * Set epoll busy poll NAPI ID from sk. */ static inline void ep_set_busy_poll_napi_id(struct epitem *epi) { #ifdef CONFIG_NET_RX_BUSY_POLL 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; #endif } |
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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. * @max_nests: Maximum number of allowed nesting calls. * @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. |
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* @ctx: This instance context. |
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* * Returns: Returns the code returned by the @nproc callback, or -1 if * the maximum recursion limit has been exceeded. |
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*/ |
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static int ep_call_nested(struct nested_calls *ncalls, int max_nests, int (*nproc)(void *, void *, int), void *priv, |
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void *cookie, void *ctx) |
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{ |
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int error, call_nests = 0; |
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unsigned long flags; |
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struct list_head *lsthead = &ncalls->tasks_call_list; struct nested_call_node *tncur; struct nested_call_node tnode; |
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|
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spin_lock_irqsave(&ncalls->lock, flags); |
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/* * 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... |
470 |
list_for_each_entry(tncur, lsthead, llink) { |
3fe4a975d epoll: fix nested... |
471 |
if (tncur->ctx == ctx && |
5071f97ec epoll: fix epoll'... |
472 |
(tncur->cookie == cookie || ++call_nests > max_nests)) { |
1da177e4c Linux-2.6.12-rc2 |
473 474 475 476 |
/* * Ops ... loop detected or maximum nest level reached. * We abort this wake by breaking the cycle itself. */ |
abff55cee epoll: don't use ... |
477 478 |
error = -1; goto out_unlock; |
1da177e4c Linux-2.6.12-rc2 |
479 480 |
} } |
5071f97ec epoll: fix epoll'... |
481 |
/* Add the current task and cookie to the list */ |
3fe4a975d epoll: fix nested... |
482 |
tnode.ctx = ctx; |
5071f97ec epoll: fix epoll'... |
483 |
tnode.cookie = cookie; |
1da177e4c Linux-2.6.12-rc2 |
484 |
list_add(&tnode.llink, lsthead); |
5071f97ec epoll: fix epoll'... |
485 |
spin_unlock_irqrestore(&ncalls->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
486 |
|
5071f97ec epoll: fix epoll'... |
487 488 |
/* Call the nested function */ error = (*nproc)(priv, cookie, call_nests); |
1da177e4c Linux-2.6.12-rc2 |
489 490 |
/* Remove the current task from the list */ |
5071f97ec epoll: fix epoll'... |
491 |
spin_lock_irqsave(&ncalls->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
492 |
list_del(&tnode.llink); |
3fe4a975d epoll: fix nested... |
493 |
out_unlock: |
5071f97ec epoll: fix epoll'... |
494 495 496 497 |
spin_unlock_irqrestore(&ncalls->lock, flags); return error; } |
02edc6fc4 epoll: comment th... |
498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 |
/* * 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... |
523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 |
#ifdef CONFIG_DEBUG_LOCK_ALLOC static inline void ep_wake_up_nested(wait_queue_head_t *wqueue, unsigned long events, int subclass) { unsigned long flags; spin_lock_irqsave_nested(&wqueue->lock, flags, subclass); wake_up_locked_poll(wqueue, events); spin_unlock_irqrestore(&wqueue->lock, flags); } #else static inline void ep_wake_up_nested(wait_queue_head_t *wqueue, unsigned long events, int subclass) { wake_up_poll(wqueue, events); } #endif |
5071f97ec epoll: fix epoll'... |
540 541 |
static int ep_poll_wakeup_proc(void *priv, void *cookie, int call_nests) { |
2dfa4eeab epoll keyed wakeu... |
542 543 |
ep_wake_up_nested((wait_queue_head_t *) cookie, POLLIN, 1 + call_nests); |
5071f97ec epoll: fix epoll'... |
544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 |
return 0; } /* * Perform a safe wake up of the poll wait list. The problem is that * with the new callback'd wake up system, it is possible that the * poll callback is reentered from inside the call to wake_up() done * on the poll wait queue head. The rule is that we cannot reenter the * wake up code from the same task more than EP_MAX_NESTS times, * and we cannot reenter the same wait queue head at all. This will * enable to have a hierarchy of epoll file descriptor of no more than * EP_MAX_NESTS deep. */ static void ep_poll_safewake(wait_queue_head_t *wq) { |
3fe4a975d epoll: fix nested... |
559 |
int this_cpu = get_cpu(); |
5071f97ec epoll: fix epoll'... |
560 |
ep_call_nested(&poll_safewake_ncalls, EP_MAX_NESTS, |
3fe4a975d epoll: fix nested... |
561 562 563 |
ep_poll_wakeup_proc, NULL, wq, (void *) (long) this_cpu); put_cpu(); |
1da177e4c Linux-2.6.12-rc2 |
564 |
} |
971316f05 epoll: ep_unregis... |
565 566 567 568 569 |
static void ep_remove_wait_queue(struct eppoll_entry *pwq) { wait_queue_head_t *whead; rcu_read_lock(); |
138e4ad67 epoll: fix race b... |
570 571 572 573 574 575 576 |
/* * 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... |
577 578 579 580 |
if (whead) remove_wait_queue(whead, &pwq->wait); rcu_read_unlock(); } |
1da177e4c Linux-2.6.12-rc2 |
581 |
/* |
d1bc90dd5 epoll: remove unn... |
582 583 584 |
* 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 |
585 |
*/ |
7699acd13 epoll cleanups: e... |
586 |
static void ep_unregister_pollwait(struct eventpoll *ep, struct epitem *epi) |
1da177e4c Linux-2.6.12-rc2 |
587 |
{ |
7699acd13 epoll cleanups: e... |
588 589 |
struct list_head *lsthead = &epi->pwqlist; struct eppoll_entry *pwq; |
1da177e4c Linux-2.6.12-rc2 |
590 |
|
d1bc90dd5 epoll: remove unn... |
591 592 |
while (!list_empty(lsthead)) { pwq = list_first_entry(lsthead, struct eppoll_entry, llink); |
1da177e4c Linux-2.6.12-rc2 |
593 |
|
d1bc90dd5 epoll: remove unn... |
594 |
list_del(&pwq->llink); |
971316f05 epoll: ep_unregis... |
595 |
ep_remove_wait_queue(pwq); |
d1bc90dd5 epoll: remove unn... |
596 |
kmem_cache_free(pwq_cache, pwq); |
1da177e4c Linux-2.6.12-rc2 |
597 |
} |
1da177e4c Linux-2.6.12-rc2 |
598 |
} |
eea1d5859 epoll: use RCU to... |
599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 |
/* 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'... |
630 631 632 633 634 635 636 637 |
/** * 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... |
638 |
* @depth: The current depth of recursive f_op->poll calls. |
67347fe4e epoll: do not tak... |
639 |
* @ep_locked: caller already holds ep->mtx |
5071f97ec epoll: fix epoll'... |
640 641 642 643 644 645 |
* * Returns: The same integer error code returned by the @sproc callback. */ static int ep_scan_ready_list(struct eventpoll *ep, int (*sproc)(struct eventpoll *, struct list_head *, void *), |
67347fe4e epoll: do not tak... |
646 |
void *priv, int depth, bool ep_locked) |
5071f97ec epoll: fix epoll'... |
647 648 649 650 |
{ int error, pwake = 0; unsigned long flags; struct epitem *epi, *nepi; |
296e236e9 epoll: fix epoll'... |
651 |
LIST_HEAD(txlist); |
5071f97ec epoll: fix epoll'... |
652 653 654 |
/* * We need to lock this because we could be hit by |
e057e15ff epoll: clean up e... |
655 |
* eventpoll_release_file() and epoll_ctl(). |
5071f97ec epoll: fix epoll'... |
656 |
*/ |
67347fe4e epoll: do not tak... |
657 658 659 |
if (!ep_locked) mutex_lock_nested(&ep->mtx, depth); |
5071f97ec epoll: fix epoll'... |
660 661 662 663 664 665 666 667 668 669 |
/* * 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. */ spin_lock_irqsave(&ep->lock, flags); |
296e236e9 epoll: fix epoll'... |
670 |
list_splice_init(&ep->rdllist, &txlist); |
5071f97ec epoll: fix epoll'... |
671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 |
ep->ovflist = NULL; spin_unlock_irqrestore(&ep->lock, flags); /* * Now call the callback function. */ error = (*sproc)(ep, &txlist, priv); spin_lock_irqsave(&ep->lock, flags); /* * 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. */ for (nepi = ep->ovflist; (epi = nepi) != NULL; 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. */ |
4d7e30d98 epoll: Add a flag... |
693 |
if (!ep_is_linked(&epi->rdllink)) { |
5071f97ec epoll: fix epoll'... |
694 |
list_add_tail(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
695 |
ep_pm_stay_awake(epi); |
4d7e30d98 epoll: Add a flag... |
696 |
} |
5071f97ec epoll: fix epoll'... |
697 698 699 700 701 702 703 704 705 706 707 708 |
} /* * 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. */ ep->ovflist = EP_UNACTIVE_PTR; /* * Quickly re-inject items left on "txlist". */ list_splice(&txlist, &ep->rdllist); |
4d7e30d98 epoll: Add a flag... |
709 |
__pm_relax(ep->ws); |
5071f97ec epoll: fix epoll'... |
710 711 712 |
if (!list_empty(&ep->rdllist)) { /* |
296e236e9 epoll: fix epoll'... |
713 714 |
* Wake up (if active) both the eventpoll wait list and * the ->poll() wait list (delayed after we release the lock). |
5071f97ec epoll: fix epoll'... |
715 716 717 718 719 720 721 |
*/ if (waitqueue_active(&ep->wq)) wake_up_locked(&ep->wq); if (waitqueue_active(&ep->poll_wait)) pwake++; } spin_unlock_irqrestore(&ep->lock, flags); |
67347fe4e epoll: do not tak... |
722 723 |
if (!ep_locked) mutex_unlock(&ep->mtx); |
5071f97ec epoll: fix epoll'... |
724 725 726 727 728 729 730 |
/* We have to call this outside the lock */ if (pwake) ep_poll_safewake(&ep->poll_wait); return error; } |
ae10b2b4e epoll: optimize E... |
731 732 733 734 735 |
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 |
736 |
/* |
7699acd13 epoll cleanups: e... |
737 |
* Removes a "struct epitem" from the eventpoll RB tree and deallocates |
c7ea76302 epoll locks chang... |
738 |
* all the associated resources. Must be called with "mtx" held. |
7699acd13 epoll cleanups: e... |
739 740 741 |
*/ static int ep_remove(struct eventpoll *ep, struct epitem *epi) { |
7699acd13 epoll cleanups: e... |
742 743 |
unsigned long flags; struct file *file = epi->ffd.file; |
1da177e4c Linux-2.6.12-rc2 |
744 745 |
/* |
7699acd13 epoll cleanups: e... |
746 747 748 749 750 751 |
* Removes poll wait queue hooks. We _have_ to do this without holding * the "ep->lock" otherwise a deadlock might occur. This because of the * sequence of the lock acquisition. Here we do "ep->lock" then the wait * queue head lock when unregistering the wait queue. The wakeup callback * will run by holding the wait queue head lock and will call our callback * that will try to get "ep->lock". |
1da177e4c Linux-2.6.12-rc2 |
752 |
*/ |
7699acd13 epoll cleanups: e... |
753 |
ep_unregister_pollwait(ep, epi); |
1da177e4c Linux-2.6.12-rc2 |
754 |
|
7699acd13 epoll cleanups: e... |
755 |
/* Remove the current item from the list of epoll hooks */ |
684999149 Rename struct fil... |
756 |
spin_lock(&file->f_lock); |
ae10b2b4e epoll: optimize E... |
757 |
list_del_rcu(&epi->fllink); |
684999149 Rename struct fil... |
758 |
spin_unlock(&file->f_lock); |
1da177e4c Linux-2.6.12-rc2 |
759 |
|
b2ac2ea62 fs/epoll: use fas... |
760 |
rb_erase_cached(&epi->rbn, &ep->rbr); |
1da177e4c Linux-2.6.12-rc2 |
761 |
|
c7ea76302 epoll locks chang... |
762 763 764 765 |
spin_lock_irqsave(&ep->lock, flags); if (ep_is_linked(&epi->rdllink)) list_del_init(&epi->rdllink); spin_unlock_irqrestore(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
766 |
|
eea1d5859 epoll: use RCU to... |
767 |
wakeup_source_unregister(ep_wakeup_source(epi)); |
ae10b2b4e epoll: optimize E... |
768 769 770 771 772 773 774 775 |
/* * 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 |
776 |
|
52bd19f76 epoll: convert ma... |
777 |
atomic_long_dec(&ep->user->epoll_watches); |
7ef9964e6 epoll: introduce ... |
778 |
|
c7ea76302 epoll locks chang... |
779 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
780 |
} |
7699acd13 epoll cleanups: e... |
781 |
static void ep_free(struct eventpoll *ep) |
1da177e4c Linux-2.6.12-rc2 |
782 |
{ |
7699acd13 epoll cleanups: e... |
783 784 |
struct rb_node *rbp; struct epitem *epi; |
1da177e4c Linux-2.6.12-rc2 |
785 |
|
7699acd13 epoll cleanups: e... |
786 787 |
/* We need to release all tasks waiting for these file */ if (waitqueue_active(&ep->poll_wait)) |
5071f97ec epoll: fix epoll'... |
788 |
ep_poll_safewake(&ep->poll_wait); |
1da177e4c Linux-2.6.12-rc2 |
789 |
|
7699acd13 epoll cleanups: e... |
790 791 792 |
/* * 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 ... |
793 |
* We do not need to hold "ep->mtx" here because the epoll file |
7699acd13 epoll cleanups: e... |
794 795 |
* 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... |
796 |
* holding "epmutex" is sufficient here. |
7699acd13 epoll cleanups: e... |
797 798 |
*/ mutex_lock(&epmutex); |
1da177e4c Linux-2.6.12-rc2 |
799 800 |
/* |
7699acd13 epoll cleanups: e... |
801 |
* Walks through the whole tree by unregistering poll callbacks. |
1da177e4c Linux-2.6.12-rc2 |
802 |
*/ |
b2ac2ea62 fs/epoll: use fas... |
803 |
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
7699acd13 epoll cleanups: e... |
804 805 806 |
epi = rb_entry(rbp, struct epitem, rbn); ep_unregister_pollwait(ep, epi); |
91cf5ab60 epoll: add a resc... |
807 |
cond_resched(); |
7699acd13 epoll cleanups: e... |
808 |
} |
1da177e4c Linux-2.6.12-rc2 |
809 810 |
/* |
7699acd13 epoll cleanups: e... |
811 812 |
* 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 ... |
813 |
* holding "epmutex" we can be sure that no file cleanup code will hit |
7699acd13 epoll cleanups: e... |
814 |
* us during this operation. So we can avoid the lock on "ep->lock". |
ddf676c38 epoll: lock ep->m... |
815 816 |
* We do not need to lock ep->mtx, either, we only do it to prevent * a lockdep warning. |
1da177e4c Linux-2.6.12-rc2 |
817 |
*/ |
ddf676c38 epoll: lock ep->m... |
818 |
mutex_lock(&ep->mtx); |
b2ac2ea62 fs/epoll: use fas... |
819 |
while ((rbp = rb_first_cached(&ep->rbr)) != NULL) { |
7699acd13 epoll cleanups: e... |
820 821 |
epi = rb_entry(rbp, struct epitem, rbn); ep_remove(ep, epi); |
91cf5ab60 epoll: add a resc... |
822 |
cond_resched(); |
7699acd13 epoll cleanups: e... |
823 |
} |
ddf676c38 epoll: lock ep->m... |
824 |
mutex_unlock(&ep->mtx); |
1da177e4c Linux-2.6.12-rc2 |
825 |
|
7699acd13 epoll cleanups: e... |
826 |
mutex_unlock(&epmutex); |
d47de16c7 fix epoll single ... |
827 |
mutex_destroy(&ep->mtx); |
7ef9964e6 epoll: introduce ... |
828 |
free_uid(ep->user); |
4d7e30d98 epoll: Add a flag... |
829 |
wakeup_source_unregister(ep->ws); |
f0ee9aabb epoll: move kfree... |
830 |
kfree(ep); |
7699acd13 epoll cleanups: e... |
831 |
} |
1da177e4c Linux-2.6.12-rc2 |
832 |
|
7699acd13 epoll cleanups: e... |
833 834 835 |
static int ep_eventpoll_release(struct inode *inode, struct file *file) { struct eventpoll *ep = file->private_data; |
1da177e4c Linux-2.6.12-rc2 |
836 |
|
f0ee9aabb epoll: move kfree... |
837 |
if (ep) |
7699acd13 epoll cleanups: e... |
838 |
ep_free(ep); |
7699acd13 epoll cleanups: e... |
839 |
|
7699acd13 epoll cleanups: e... |
840 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
841 |
} |
450d89ec0 epoll: cleanup: h... |
842 843 844 845 846 847 |
static inline unsigned int ep_item_poll(struct epitem *epi, poll_table *pt) { pt->_key = epi->event.events; return epi->ffd.file->f_op->poll(epi->ffd.file, pt) & epi->event.events; } |
296e236e9 epoll: fix epoll'... |
848 849 |
static int ep_read_events_proc(struct eventpoll *ep, struct list_head *head, void *priv) |
5071f97ec epoll: fix epoll'... |
850 851 |
{ struct epitem *epi, *tmp; |
626cf2366 poll: add poll_re... |
852 |
poll_table pt; |
5071f97ec epoll: fix epoll'... |
853 |
|
626cf2366 poll: add poll_re... |
854 |
init_poll_funcptr(&pt, NULL); |
450d89ec0 epoll: cleanup: h... |
855 |
|
5071f97ec epoll: fix epoll'... |
856 |
list_for_each_entry_safe(epi, tmp, head, rdllink) { |
450d89ec0 epoll: cleanup: h... |
857 |
if (ep_item_poll(epi, &pt)) |
5071f97ec epoll: fix epoll'... |
858 |
return POLLIN | POLLRDNORM; |
296e236e9 epoll: fix epoll'... |
859 |
else { |
5071f97ec epoll: fix epoll'... |
860 861 862 863 864 |
/* * 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... |
865 |
__pm_relax(ep_wakeup_source(epi)); |
5071f97ec epoll: fix epoll'... |
866 |
list_del_init(&epi->rdllink); |
296e236e9 epoll: fix epoll'... |
867 |
} |
5071f97ec epoll: fix epoll'... |
868 869 870 871 |
} return 0; } |
67347fe4e epoll: do not tak... |
872 873 874 875 876 877 878 |
static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead, poll_table *pt); struct readyevents_arg { struct eventpoll *ep; bool locked; }; |
5071f97ec epoll: fix epoll'... |
879 880 |
static int ep_poll_readyevents_proc(void *priv, void *cookie, int call_nests) { |
67347fe4e epoll: do not tak... |
881 882 883 884 |
struct readyevents_arg *arg = priv; return ep_scan_ready_list(arg->ep, ep_read_events_proc, NULL, call_nests + 1, arg->locked); |
5071f97ec epoll: fix epoll'... |
885 |
} |
7699acd13 epoll cleanups: e... |
886 887 |
static unsigned int ep_eventpoll_poll(struct file *file, poll_table *wait) { |
5071f97ec epoll: fix epoll'... |
888 |
int pollflags; |
7699acd13 epoll cleanups: e... |
889 |
struct eventpoll *ep = file->private_data; |
67347fe4e epoll: do not tak... |
890 891 892 893 894 895 896 897 |
struct readyevents_arg arg; /* * During ep_insert() we already hold the ep->mtx for the tfile. * Prevent re-aquisition. */ arg.locked = wait && (wait->_qproc == ep_ptable_queue_proc); arg.ep = ep; |
1da177e4c Linux-2.6.12-rc2 |
898 |
|
7699acd13 epoll cleanups: e... |
899 900 |
/* Insert inside our poll wait queue */ poll_wait(file, &ep->poll_wait, wait); |
5071f97ec epoll: fix epoll'... |
901 902 903 904 905 906 907 |
/* * Proceed to find out if wanted events are really available inside * the ready list. This need to be done under ep_call_nested() * supervision, since the call to f_op->poll() done on listed files * could re-enter here. */ pollflags = ep_call_nested(&poll_readywalk_ncalls, EP_MAX_NESTS, |
67347fe4e epoll: do not tak... |
908 |
ep_poll_readyevents_proc, &arg, ep, current); |
7699acd13 epoll cleanups: e... |
909 |
|
296e236e9 epoll: fix epoll'... |
910 |
return pollflags != -1 ? pollflags : 0; |
7699acd13 epoll cleanups: e... |
911 |
} |
138d22b58 fs, epoll: add pr... |
912 |
#ifdef CONFIG_PROC_FS |
a3816ab0e fs: Convert show_... |
913 |
static void ep_show_fdinfo(struct seq_file *m, struct file *f) |
138d22b58 fs, epoll: add pr... |
914 915 916 |
{ struct eventpoll *ep = f->private_data; struct rb_node *rbp; |
138d22b58 fs, epoll: add pr... |
917 918 |
mutex_lock(&ep->mtx); |
b2ac2ea62 fs/epoll: use fas... |
919 |
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
138d22b58 fs, epoll: add pr... |
920 |
struct epitem *epi = rb_entry(rbp, struct epitem, rbn); |
77493f04b procfs: fdinfo: e... |
921 |
struct inode *inode = file_inode(epi->ffd.file); |
138d22b58 fs, epoll: add pr... |
922 |
|
77493f04b procfs: fdinfo: e... |
923 924 925 |
seq_printf(m, "tfd: %8d events: %8x data: %16llx " " pos:%lli ino:%lx sdev:%x ", |
a3816ab0e fs: Convert show_... |
926 |
epi->ffd.fd, epi->event.events, |
77493f04b procfs: fdinfo: e... |
927 928 929 |
(long long)epi->event.data, (long long)epi->ffd.file->f_pos, inode->i_ino, inode->i_sb->s_dev); |
a3816ab0e fs: Convert show_... |
930 |
if (seq_has_overflowed(m)) |
138d22b58 fs, epoll: add pr... |
931 932 933 |
break; } mutex_unlock(&ep->mtx); |
138d22b58 fs, epoll: add pr... |
934 935 |
} #endif |
7699acd13 epoll cleanups: e... |
936 937 |
/* File callbacks that implement the eventpoll file behaviour */ static const struct file_operations eventpoll_fops = { |
138d22b58 fs, epoll: add pr... |
938 939 940 |
#ifdef CONFIG_PROC_FS .show_fdinfo = ep_show_fdinfo, #endif |
7699acd13 epoll cleanups: e... |
941 |
.release = ep_eventpoll_release, |
6038f373a llseek: automatic... |
942 943 |
.poll = ep_eventpoll_poll, .llseek = noop_llseek, |
7699acd13 epoll cleanups: e... |
944 |
}; |
b611967de [PATCH] epoll_pwa... |
945 |
/* |
7699acd13 epoll cleanups: e... |
946 947 948 |
* 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... |
949 |
*/ |
7699acd13 epoll cleanups: e... |
950 |
void eventpoll_release_file(struct file *file) |
b611967de [PATCH] epoll_pwa... |
951 |
{ |
7699acd13 epoll cleanups: e... |
952 |
struct eventpoll *ep; |
ebe06187b epoll: fix use-af... |
953 |
struct epitem *epi, *next; |
b611967de [PATCH] epoll_pwa... |
954 955 |
/* |
684999149 Rename struct fil... |
956 |
* We don't want to get "file->f_lock" because it is not |
7699acd13 epoll cleanups: e... |
957 |
* necessary. It is not necessary because we're in the "struct file" |
25985edce Fix common misspe... |
958 |
* cleanup path, and this means that no one is using this file anymore. |
5071f97ec epoll: fix epoll'... |
959 |
* So, for example, epoll_ctl() cannot hit here since if we reach this |
67647d0fb epoll: fix some c... |
960 |
* point, the file counter already went to zero and fget() would fail. |
d47de16c7 fix epoll single ... |
961 |
* The only hit might come from ep_free() but by holding the mutex |
7699acd13 epoll cleanups: e... |
962 |
* will correctly serialize the operation. We do need to acquire |
d47de16c7 fix epoll single ... |
963 |
* "ep->mtx" after "epmutex" because ep_remove() requires it when called |
7699acd13 epoll cleanups: e... |
964 |
* from anywhere but ep_free(). |
684999149 Rename struct fil... |
965 966 |
* * Besides, ep_remove() acquires the lock, so we can't hold it here. |
b611967de [PATCH] epoll_pwa... |
967 |
*/ |
7699acd13 epoll cleanups: e... |
968 |
mutex_lock(&epmutex); |
ebe06187b epoll: fix use-af... |
969 |
list_for_each_entry_safe(epi, next, &file->f_ep_links, fllink) { |
7699acd13 epoll cleanups: e... |
970 |
ep = epi->ep; |
d8805e633 epoll: fix spurio... |
971 |
mutex_lock_nested(&ep->mtx, 0); |
7699acd13 epoll cleanups: e... |
972 |
ep_remove(ep, epi); |
d47de16c7 fix epoll single ... |
973 |
mutex_unlock(&ep->mtx); |
b611967de [PATCH] epoll_pwa... |
974 |
} |
7699acd13 epoll cleanups: e... |
975 |
mutex_unlock(&epmutex); |
b611967de [PATCH] epoll_pwa... |
976 |
} |
53d2be79d [PATCH] epoll: fi... |
977 |
static int ep_alloc(struct eventpoll **pep) |
1da177e4c Linux-2.6.12-rc2 |
978 |
{ |
7ef9964e6 epoll: introduce ... |
979 980 981 |
int error; struct user_struct *user; struct eventpoll *ep; |
1da177e4c Linux-2.6.12-rc2 |
982 |
|
7ef9964e6 epoll: introduce ... |
983 |
user = get_current_user(); |
7ef9964e6 epoll: introduce ... |
984 985 986 987 |
error = -ENOMEM; ep = kzalloc(sizeof(*ep), GFP_KERNEL); if (unlikely(!ep)) goto free_uid; |
1da177e4c Linux-2.6.12-rc2 |
988 |
|
c7ea76302 epoll locks chang... |
989 |
spin_lock_init(&ep->lock); |
d47de16c7 fix epoll single ... |
990 |
mutex_init(&ep->mtx); |
1da177e4c Linux-2.6.12-rc2 |
991 992 993 |
init_waitqueue_head(&ep->wq); init_waitqueue_head(&ep->poll_wait); INIT_LIST_HEAD(&ep->rdllist); |
b2ac2ea62 fs/epoll: use fas... |
994 |
ep->rbr = RB_ROOT_CACHED; |
d47de16c7 fix epoll single ... |
995 |
ep->ovflist = EP_UNACTIVE_PTR; |
7ef9964e6 epoll: introduce ... |
996 |
ep->user = user; |
1da177e4c Linux-2.6.12-rc2 |
997 |
|
53d2be79d [PATCH] epoll: fi... |
998 |
*pep = ep; |
1da177e4c Linux-2.6.12-rc2 |
999 |
|
1da177e4c Linux-2.6.12-rc2 |
1000 |
return 0; |
7ef9964e6 epoll: introduce ... |
1001 1002 1003 1004 |
free_uid: free_uid(user); return error; |
1da177e4c Linux-2.6.12-rc2 |
1005 |
} |
1da177e4c Linux-2.6.12-rc2 |
1006 |
/* |
c7ea76302 epoll locks chang... |
1007 1008 1009 |
* 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 |
1010 1011 1012 1013 |
*/ static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd) { int kcmp; |
1da177e4c Linux-2.6.12-rc2 |
1014 1015 1016 |
struct rb_node *rbp; struct epitem *epi, *epir = NULL; struct epoll_filefd ffd; |
b030a4dd6 [PATCH] Remove ev... |
1017 |
ep_set_ffd(&ffd, file, fd); |
b2ac2ea62 fs/epoll: use fas... |
1018 |
for (rbp = ep->rbr.rb_root.rb_node; rbp; ) { |
1da177e4c Linux-2.6.12-rc2 |
1019 |
epi = rb_entry(rbp, struct epitem, rbn); |
b030a4dd6 [PATCH] Remove ev... |
1020 |
kcmp = ep_cmp_ffd(&ffd, &epi->ffd); |
1da177e4c Linux-2.6.12-rc2 |
1021 1022 1023 1024 1025 |
if (kcmp > 0) rbp = rbp->rb_right; else if (kcmp < 0) rbp = rbp->rb_left; else { |
1da177e4c Linux-2.6.12-rc2 |
1026 1027 1028 1029 |
epir = epi; break; } } |
1da177e4c Linux-2.6.12-rc2 |
1030 |
|
1da177e4c Linux-2.6.12-rc2 |
1031 1032 |
return epir; } |
92ef6da3d kcmp: fs/epoll: w... |
1033 |
#ifdef CONFIG_CHECKPOINT_RESTORE |
0791e3644 kcmp: add KCMP_EP... |
1034 1035 1036 1037 |
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... |
1038 |
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
0791e3644 kcmp: add KCMP_EP... |
1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 |
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... |
1074 |
#endif /* CONFIG_CHECKPOINT_RESTORE */ |
0791e3644 kcmp: add KCMP_EP... |
1075 |
|
1da177e4c Linux-2.6.12-rc2 |
1076 |
/* |
7699acd13 epoll cleanups: e... |
1077 |
* This is the callback that is passed to the wait queue wakeup |
bf6a41db7 fs/eventpoll.c: f... |
1078 |
* mechanism. It is called by the stored file descriptors when they |
7699acd13 epoll cleanups: e... |
1079 |
* have events to report. |
1da177e4c Linux-2.6.12-rc2 |
1080 |
*/ |
ac6424b98 sched/wait: Renam... |
1081 |
static int ep_poll_callback(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) |
1da177e4c Linux-2.6.12-rc2 |
1082 |
{ |
7699acd13 epoll cleanups: e... |
1083 1084 1085 1086 |
int pwake = 0; unsigned long flags; struct epitem *epi = ep_item_from_wait(wait); struct eventpoll *ep = epi->ep; |
df0108c5d epoll: add EPOLLE... |
1087 |
int ewake = 0; |
1da177e4c Linux-2.6.12-rc2 |
1088 |
|
c7ea76302 epoll locks chang... |
1089 |
spin_lock_irqsave(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1090 |
|
bf3b9f637 epoll: Add busy p... |
1091 |
ep_set_busy_poll_napi_id(epi); |
7699acd13 epoll cleanups: e... |
1092 1093 1094 1095 1096 1097 1098 |
/* * 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 ... |
1099 1100 1101 |
goto out_unlock; /* |
2dfa4eeab epoll keyed wakeu... |
1102 1103 1104 1105 1106 1107 1108 1109 1110 |
* 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. */ if (key && !((unsigned long) key & epi->event.events)) goto out_unlock; /* |
bf6a41db7 fs/eventpoll.c: f... |
1111 |
* If we are transferring events to userspace, we can hold no locks |
d47de16c7 fix epoll single ... |
1112 |
* (because we're accessing user memory, and because of linux f_op->poll() |
bf6a41db7 fs/eventpoll.c: f... |
1113 |
* semantics). All the events that happen during that period of time are |
d47de16c7 fix epoll single ... |
1114 1115 1116 1117 1118 1119 |
* chained in ep->ovflist and requeued later on. */ if (unlikely(ep->ovflist != EP_UNACTIVE_PTR)) { if (epi->next == EP_UNACTIVE_PTR) { epi->next = ep->ovflist; ep->ovflist = epi; |
4d7e30d98 epoll: Add a flag... |
1120 1121 1122 1123 1124 1125 1126 |
if (epi->ws) { /* * Activate ep->ws since epi->ws may get * deactivated at any time. */ __pm_stay_awake(ep->ws); } |
d47de16c7 fix epoll single ... |
1127 1128 1129 |
} goto out_unlock; } |
1da177e4c Linux-2.6.12-rc2 |
1130 |
|
7699acd13 epoll cleanups: e... |
1131 |
/* If this file is already in the ready list we exit soon */ |
4d7e30d98 epoll: Add a flag... |
1132 |
if (!ep_is_linked(&epi->rdllink)) { |
5071f97ec epoll: fix epoll'... |
1133 |
list_add_tail(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
1134 |
ep_pm_stay_awake_rcu(epi); |
4d7e30d98 epoll: Add a flag... |
1135 |
} |
7699acd13 epoll cleanups: e... |
1136 |
|
7699acd13 epoll cleanups: e... |
1137 1138 1139 1140 |
/* * Wake up ( if active ) both the eventpoll wait list and the ->poll() * wait list. */ |
df0108c5d epoll: add EPOLLE... |
1141 |
if (waitqueue_active(&ep->wq)) { |
b6a515c8a epoll: restrict E... |
1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 |
if ((epi->event.events & EPOLLEXCLUSIVE) && !((unsigned long)key & POLLFREE)) { switch ((unsigned long)key & EPOLLINOUT_BITS) { case POLLIN: if (epi->event.events & POLLIN) ewake = 1; break; case POLLOUT: if (epi->event.events & POLLOUT) ewake = 1; break; case 0: ewake = 1; break; } } |
4a6e9e2ce Use wake_up_locke... |
1158 |
wake_up_locked(&ep->wq); |
df0108c5d epoll: add EPOLLE... |
1159 |
} |
7699acd13 epoll cleanups: e... |
1160 1161 |
if (waitqueue_active(&ep->poll_wait)) pwake++; |
d47de16c7 fix epoll single ... |
1162 |
out_unlock: |
c7ea76302 epoll locks chang... |
1163 |
spin_unlock_irqrestore(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1164 |
|
7699acd13 epoll cleanups: e... |
1165 1166 |
/* We have to call this outside the lock */ if (pwake) |
5071f97ec epoll: fix epoll'... |
1167 |
ep_poll_safewake(&ep->poll_wait); |
7699acd13 epoll cleanups: e... |
1168 |
|
138e4ad67 epoll: fix race b... |
1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 |
if (!(epi->event.events & EPOLLEXCLUSIVE)) ewake = 1; if ((unsigned long)key & POLLFREE) { /* * 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... |
1187 |
|
138e4ad67 epoll: fix race b... |
1188 |
return ewake; |
7699acd13 epoll cleanups: e... |
1189 |
} |
1da177e4c Linux-2.6.12-rc2 |
1190 1191 1192 1193 1194 1195 1196 1197 |
/* * 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... |
1198 |
struct epitem *epi = ep_item_from_epqueue(pt); |
1da177e4c Linux-2.6.12-rc2 |
1199 |
struct eppoll_entry *pwq; |
e94b17660 [PATCH] slab: rem... |
1200 |
if (epi->nwait >= 0 && (pwq = kmem_cache_alloc(pwq_cache, GFP_KERNEL))) { |
1da177e4c Linux-2.6.12-rc2 |
1201 1202 1203 |
init_waitqueue_func_entry(&pwq->wait, ep_poll_callback); pwq->whead = whead; pwq->base = epi; |
df0108c5d epoll: add EPOLLE... |
1204 1205 1206 1207 |
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 |
1208 1209 |
list_add_tail(&pwq->llink, &epi->pwqlist); epi->nwait++; |
296e236e9 epoll: fix epoll'... |
1210 |
} else { |
1da177e4c Linux-2.6.12-rc2 |
1211 1212 |
/* We have to signal that an error occurred */ epi->nwait = -1; |
296e236e9 epoll: fix epoll'... |
1213 |
} |
1da177e4c Linux-2.6.12-rc2 |
1214 |
} |
1da177e4c Linux-2.6.12-rc2 |
1215 1216 1217 |
static void ep_rbtree_insert(struct eventpoll *ep, struct epitem *epi) { int kcmp; |
b2ac2ea62 fs/epoll: use fas... |
1218 |
struct rb_node **p = &ep->rbr.rb_root.rb_node, *parent = NULL; |
1da177e4c Linux-2.6.12-rc2 |
1219 |
struct epitem *epic; |
b2ac2ea62 fs/epoll: use fas... |
1220 |
bool leftmost = true; |
1da177e4c Linux-2.6.12-rc2 |
1221 1222 1223 1224 |
while (*p) { parent = *p; epic = rb_entry(parent, struct epitem, rbn); |
b030a4dd6 [PATCH] Remove ev... |
1225 |
kcmp = ep_cmp_ffd(&epi->ffd, &epic->ffd); |
b2ac2ea62 fs/epoll: use fas... |
1226 |
if (kcmp > 0) { |
1da177e4c Linux-2.6.12-rc2 |
1227 |
p = &parent->rb_right; |
b2ac2ea62 fs/epoll: use fas... |
1228 1229 |
leftmost = false; } else |
1da177e4c Linux-2.6.12-rc2 |
1230 1231 1232 |
p = &parent->rb_left; } rb_link_node(&epi->rbn, parent, p); |
b2ac2ea62 fs/epoll: use fas... |
1233 |
rb_insert_color_cached(&epi->rbn, &ep->rbr, leftmost); |
1da177e4c Linux-2.6.12-rc2 |
1234 |
} |
a80a6b85b revert "epoll: su... |
1235 |
|
28d82dc1c epoll: limit paths |
1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 |
#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... |
1253 1254 1255 |
/* Allow an arbitrary number of depth 1 paths */ if (nests == 0) return 0; |
28d82dc1c epoll: limit paths |
1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 |
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... |
1275 1276 1277 |
/* 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 |
1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 |
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, EP_MAX_NESTS, 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... |
1300 |
rcu_read_unlock(); |
28d82dc1c epoll: limit paths |
1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 |
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 |
1316 1317 1318 1319 1320 |
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 |
1321 1322 1323 1324 1325 1326 1327 1328 1329 |
path_count_init(); error = ep_call_nested(&poll_loop_ncalls, EP_MAX_NESTS, reverse_path_check_proc, current_file, current_file, current); if (error) break; } return error; } |
4d7e30d98 epoll: Add a flag... |
1330 1331 1332 |
static int ep_create_wakeup_source(struct epitem *epi) { const char *name; |
eea1d5859 epoll: use RCU to... |
1333 |
struct wakeup_source *ws; |
4d7e30d98 epoll: Add a flag... |
1334 1335 1336 1337 1338 1339 1340 1341 |
if (!epi->ep->ws) { epi->ep->ws = wakeup_source_register("eventpoll"); if (!epi->ep->ws) return -ENOMEM; } name = epi->ffd.file->f_path.dentry->d_name.name; |
eea1d5859 epoll: use RCU to... |
1342 1343 1344 |
ws = wakeup_source_register(name); if (!ws) |
4d7e30d98 epoll: Add a flag... |
1345 |
return -ENOMEM; |
eea1d5859 epoll: use RCU to... |
1346 |
rcu_assign_pointer(epi->ws, ws); |
4d7e30d98 epoll: Add a flag... |
1347 1348 1349 |
return 0; } |
eea1d5859 epoll: use RCU to... |
1350 1351 |
/* 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... |
1352 |
{ |
eea1d5859 epoll: use RCU to... |
1353 |
struct wakeup_source *ws = ep_wakeup_source(epi); |
d6d67e723 epoll: cleanup: u... |
1354 |
RCU_INIT_POINTER(epi->ws, NULL); |
eea1d5859 epoll: use RCU to... |
1355 1356 1357 1358 1359 1360 1361 1362 |
/* * 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... |
1363 |
} |
c7ea76302 epoll locks chang... |
1364 1365 1366 |
/* * Must be called with "mtx" held. */ |
1da177e4c Linux-2.6.12-rc2 |
1367 |
static int ep_insert(struct eventpoll *ep, struct epoll_event *event, |
67347fe4e epoll: do not tak... |
1368 |
struct file *tfile, int fd, int full_check) |
1da177e4c Linux-2.6.12-rc2 |
1369 1370 1371 |
{ int error, revents, pwake = 0; unsigned long flags; |
52bd19f76 epoll: convert ma... |
1372 |
long user_watches; |
1da177e4c Linux-2.6.12-rc2 |
1373 1374 |
struct epitem *epi; struct ep_pqueue epq; |
52bd19f76 epoll: convert ma... |
1375 1376 |
user_watches = atomic_long_read(&ep->user->epoll_watches); if (unlikely(user_watches >= max_user_watches)) |
7ef9964e6 epoll: introduce ... |
1377 |
return -ENOSPC; |
e94b17660 [PATCH] slab: rem... |
1378 |
if (!(epi = kmem_cache_alloc(epi_cache, GFP_KERNEL))) |
7ef9964e6 epoll: introduce ... |
1379 |
return -ENOMEM; |
1da177e4c Linux-2.6.12-rc2 |
1380 1381 |
/* Item initialization follow here ... */ |
1da177e4c Linux-2.6.12-rc2 |
1382 1383 |
INIT_LIST_HEAD(&epi->rdllink); INIT_LIST_HEAD(&epi->fllink); |
1da177e4c Linux-2.6.12-rc2 |
1384 1385 |
INIT_LIST_HEAD(&epi->pwqlist); epi->ep = ep; |
b030a4dd6 [PATCH] Remove ev... |
1386 |
ep_set_ffd(&epi->ffd, tfile, fd); |
1da177e4c Linux-2.6.12-rc2 |
1387 |
epi->event = *event; |
1da177e4c Linux-2.6.12-rc2 |
1388 |
epi->nwait = 0; |
d47de16c7 fix epoll single ... |
1389 |
epi->next = EP_UNACTIVE_PTR; |
4d7e30d98 epoll: Add a flag... |
1390 1391 1392 1393 1394 |
if (epi->event.events & EPOLLWAKEUP) { error = ep_create_wakeup_source(epi); if (error) goto error_create_wakeup_source; } else { |
eea1d5859 epoll: use RCU to... |
1395 |
RCU_INIT_POINTER(epi->ws, NULL); |
4d7e30d98 epoll: Add a flag... |
1396 |
} |
1da177e4c Linux-2.6.12-rc2 |
1397 1398 1399 1400 1401 1402 1403 1404 |
/* 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... |
1405 1406 1407 |
* 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 |
1408 |
*/ |
450d89ec0 epoll: cleanup: h... |
1409 |
revents = ep_item_poll(epi, &epq.pt); |
1da177e4c Linux-2.6.12-rc2 |
1410 1411 1412 1413 1414 1415 |
/* * 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 ... |
1416 |
error = -ENOMEM; |
1da177e4c Linux-2.6.12-rc2 |
1417 |
if (epi->nwait < 0) |
7699acd13 epoll cleanups: e... |
1418 |
goto error_unregister; |
1da177e4c Linux-2.6.12-rc2 |
1419 1420 |
/* Add the current item to the list of active epoll hook for this file */ |
684999149 Rename struct fil... |
1421 |
spin_lock(&tfile->f_lock); |
ae10b2b4e epoll: optimize E... |
1422 |
list_add_tail_rcu(&epi->fllink, &tfile->f_ep_links); |
684999149 Rename struct fil... |
1423 |
spin_unlock(&tfile->f_lock); |
1da177e4c Linux-2.6.12-rc2 |
1424 |
|
c7ea76302 epoll locks chang... |
1425 1426 1427 1428 |
/* * Add the current item to the RB tree. All RB tree operations are * protected by "mtx", and ep_insert() is called with "mtx" held. */ |
1da177e4c Linux-2.6.12-rc2 |
1429 |
ep_rbtree_insert(ep, epi); |
28d82dc1c epoll: limit paths |
1430 1431 |
/* now check if we've created too many backpaths */ error = -EINVAL; |
67347fe4e epoll: do not tak... |
1432 |
if (full_check && reverse_path_check()) |
28d82dc1c epoll: limit paths |
1433 |
goto error_remove_epi; |
c7ea76302 epoll locks chang... |
1434 1435 |
/* We have to drop the new item inside our item list to keep track of it */ spin_lock_irqsave(&ep->lock, flags); |
bf3b9f637 epoll: Add busy p... |
1436 1437 |
/* record NAPI ID of new item if present */ ep_set_busy_poll_napi_id(epi); |
1da177e4c Linux-2.6.12-rc2 |
1438 |
/* If the file is already "ready" we drop it inside the ready list */ |
b030a4dd6 [PATCH] Remove ev... |
1439 |
if ((revents & event->events) && !ep_is_linked(&epi->rdllink)) { |
1da177e4c Linux-2.6.12-rc2 |
1440 |
list_add_tail(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
1441 |
ep_pm_stay_awake(epi); |
1da177e4c Linux-2.6.12-rc2 |
1442 1443 1444 |
/* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) |
4a6e9e2ce Use wake_up_locke... |
1445 |
wake_up_locked(&ep->wq); |
1da177e4c Linux-2.6.12-rc2 |
1446 1447 1448 |
if (waitqueue_active(&ep->poll_wait)) pwake++; } |
c7ea76302 epoll locks chang... |
1449 |
spin_unlock_irqrestore(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1450 |
|
52bd19f76 epoll: convert ma... |
1451 |
atomic_long_inc(&ep->user->epoll_watches); |
7ef9964e6 epoll: introduce ... |
1452 |
|
1da177e4c Linux-2.6.12-rc2 |
1453 1454 |
/* We have to call this outside the lock */ if (pwake) |
5071f97ec epoll: fix epoll'... |
1455 |
ep_poll_safewake(&ep->poll_wait); |
1da177e4c Linux-2.6.12-rc2 |
1456 |
|
1da177e4c Linux-2.6.12-rc2 |
1457 |
return 0; |
28d82dc1c epoll: limit paths |
1458 1459 |
error_remove_epi: spin_lock(&tfile->f_lock); |
ae10b2b4e epoll: optimize E... |
1460 |
list_del_rcu(&epi->fllink); |
28d82dc1c epoll: limit paths |
1461 |
spin_unlock(&tfile->f_lock); |
b2ac2ea62 fs/epoll: use fas... |
1462 |
rb_erase_cached(&epi->rbn, &ep->rbr); |
28d82dc1c epoll: limit paths |
1463 |
|
7699acd13 epoll cleanups: e... |
1464 |
error_unregister: |
1da177e4c Linux-2.6.12-rc2 |
1465 1466 1467 1468 |
ep_unregister_pollwait(ep, epi); /* * We need to do this because an event could have been arrived on some |
67647d0fb epoll: fix some c... |
1469 1470 1471 |
* 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 |
1472 |
*/ |
c7ea76302 epoll locks chang... |
1473 |
spin_lock_irqsave(&ep->lock, flags); |
b030a4dd6 [PATCH] Remove ev... |
1474 |
if (ep_is_linked(&epi->rdllink)) |
6192bd536 epoll: optimizati... |
1475 |
list_del_init(&epi->rdllink); |
c7ea76302 epoll locks chang... |
1476 |
spin_unlock_irqrestore(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1477 |
|
eea1d5859 epoll: use RCU to... |
1478 |
wakeup_source_unregister(ep_wakeup_source(epi)); |
4d7e30d98 epoll: Add a flag... |
1479 1480 |
error_create_wakeup_source: |
b030a4dd6 [PATCH] Remove ev... |
1481 |
kmem_cache_free(epi_cache, epi); |
7ef9964e6 epoll: introduce ... |
1482 |
|
1da177e4c Linux-2.6.12-rc2 |
1483 1484 |
return error; } |
1da177e4c Linux-2.6.12-rc2 |
1485 1486 |
/* * Modify the interest event mask by dropping an event if the new mask |
c7ea76302 epoll locks chang... |
1487 |
* has a match in the current file status. Must be called with "mtx" held. |
1da177e4c Linux-2.6.12-rc2 |
1488 1489 1490 1491 1492 |
*/ static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_event *event) { int pwake = 0; unsigned int revents; |
626cf2366 poll: add poll_re... |
1493 1494 1495 |
poll_table pt; init_poll_funcptr(&pt, NULL); |
1da177e4c Linux-2.6.12-rc2 |
1496 1497 |
/* |
e057e15ff epoll: clean up e... |
1498 1499 1500 |
* 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 |
1501 |
*/ |
128dd1759 epoll: prevent mi... |
1502 |
epi->event.events = event->events; /* need barrier below */ |
e057e15ff epoll: clean up e... |
1503 |
epi->event.data = event->data; /* protected by mtx */ |
4d7e30d98 epoll: Add a flag... |
1504 |
if (epi->event.events & EPOLLWAKEUP) { |
eea1d5859 epoll: use RCU to... |
1505 |
if (!ep_has_wakeup_source(epi)) |
4d7e30d98 epoll: Add a flag... |
1506 |
ep_create_wakeup_source(epi); |
eea1d5859 epoll: use RCU to... |
1507 |
} else if (ep_has_wakeup_source(epi)) { |
4d7e30d98 epoll: Add a flag... |
1508 1509 |
ep_destroy_wakeup_source(epi); } |
1da177e4c Linux-2.6.12-rc2 |
1510 1511 |
/* |
128dd1759 epoll: prevent mi... |
1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 |
* 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(). * We need this because we did not take ep->lock while * changing epi above (but ep_poll_callback does take * ep->lock). * * 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 |
1532 1533 1534 |
* Get current event bits. We can safely use the file* here because * its usage count has been increased by the caller of this function. */ |
450d89ec0 epoll: cleanup: h... |
1535 |
revents = ep_item_poll(epi, &pt); |
1da177e4c Linux-2.6.12-rc2 |
1536 |
|
1da177e4c Linux-2.6.12-rc2 |
1537 |
/* |
c7ea76302 epoll locks chang... |
1538 |
* If the item is "hot" and it is not registered inside the ready |
67647d0fb epoll: fix some c... |
1539 |
* list, push it inside. |
1da177e4c Linux-2.6.12-rc2 |
1540 |
*/ |
c7ea76302 epoll locks chang... |
1541 |
if (revents & event->events) { |
e057e15ff epoll: clean up e... |
1542 |
spin_lock_irq(&ep->lock); |
c7ea76302 epoll locks chang... |
1543 1544 |
if (!ep_is_linked(&epi->rdllink)) { list_add_tail(&epi->rdllink, &ep->rdllist); |
eea1d5859 epoll: use RCU to... |
1545 |
ep_pm_stay_awake(epi); |
c7ea76302 epoll locks chang... |
1546 1547 1548 |
/* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) |
4a6e9e2ce Use wake_up_locke... |
1549 |
wake_up_locked(&ep->wq); |
c7ea76302 epoll locks chang... |
1550 1551 |
if (waitqueue_active(&ep->poll_wait)) pwake++; |
7699acd13 epoll cleanups: e... |
1552 |
} |
e057e15ff epoll: clean up e... |
1553 |
spin_unlock_irq(&ep->lock); |
7699acd13 epoll cleanups: e... |
1554 |
} |
1da177e4c Linux-2.6.12-rc2 |
1555 |
|
7699acd13 epoll cleanups: e... |
1556 1557 |
/* We have to call this outside the lock */ if (pwake) |
5071f97ec epoll: fix epoll'... |
1558 |
ep_poll_safewake(&ep->poll_wait); |
1da177e4c Linux-2.6.12-rc2 |
1559 |
|
7699acd13 epoll cleanups: e... |
1560 |
return 0; |
1da177e4c Linux-2.6.12-rc2 |
1561 |
} |
296e236e9 epoll: fix epoll'... |
1562 1563 |
static int ep_send_events_proc(struct eventpoll *ep, struct list_head *head, void *priv) |
1da177e4c Linux-2.6.12-rc2 |
1564 |
{ |
5071f97ec epoll: fix epoll'... |
1565 1566 |
struct ep_send_events_data *esed = priv; int eventcnt; |
296e236e9 epoll: fix epoll'... |
1567 |
unsigned int revents; |
5071f97ec epoll: fix epoll'... |
1568 1569 |
struct epitem *epi; struct epoll_event __user *uevent; |
eea1d5859 epoll: use RCU to... |
1570 |
struct wakeup_source *ws; |
626cf2366 poll: add poll_re... |
1571 1572 1573 |
poll_table pt; init_poll_funcptr(&pt, NULL); |
1da177e4c Linux-2.6.12-rc2 |
1574 |
|
296e236e9 epoll: fix epoll'... |
1575 |
/* |
5071f97ec epoll: fix epoll'... |
1576 1577 1578 |
* 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'... |
1579 |
*/ |
5071f97ec epoll: fix epoll'... |
1580 1581 1582 |
for (eventcnt = 0, uevent = esed->events; !list_empty(head) && eventcnt < esed->maxevents;) { epi = list_first_entry(head, struct epitem, rdllink); |
d47de16c7 fix epoll single ... |
1583 |
|
4d7e30d98 epoll: Add a flag... |
1584 1585 1586 1587 1588 1589 1590 1591 1592 |
/* * 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... |
1593 1594 1595 1596 1597 1598 |
ws = ep_wakeup_source(epi); if (ws) { if (ws->active) __pm_stay_awake(ep->ws); __pm_relax(ws); } |
d47de16c7 fix epoll single ... |
1599 |
list_del_init(&epi->rdllink); |
1da177e4c Linux-2.6.12-rc2 |
1600 |
|
450d89ec0 epoll: cleanup: h... |
1601 |
revents = ep_item_poll(epi, &pt); |
5071f97ec epoll: fix epoll'... |
1602 |
|
296e236e9 epoll: fix epoll'... |
1603 |
/* |
5071f97ec epoll: fix epoll'... |
1604 1605 1606 1607 |
* If the event mask intersect the caller-requested one, * deliver the event to userspace. Again, ep_scan_ready_list() * is holding "mtx", so no operations coming from userspace * can change the item. |
296e236e9 epoll: fix epoll'... |
1608 1609 |
*/ if (revents) { |
5071f97ec epoll: fix epoll'... |
1610 |
if (__put_user(revents, &uevent->events) || |
d03058828 epoll: remember t... |
1611 1612 |
__put_user(epi->event.data, &uevent->data)) { list_add(&epi->rdllink, head); |
eea1d5859 epoll: use RCU to... |
1613 |
ep_pm_stay_awake(epi); |
296e236e9 epoll: fix epoll'... |
1614 |
return eventcnt ? eventcnt : -EFAULT; |
d03058828 epoll: remember t... |
1615 |
} |
296e236e9 epoll: fix epoll'... |
1616 |
eventcnt++; |
5071f97ec epoll: fix epoll'... |
1617 |
uevent++; |
296e236e9 epoll: fix epoll'... |
1618 1619 1620 1621 1622 1623 1624 1625 |
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 |
25985edce Fix common misspe... |
1626 |
* availability. At this point, no one can insert |
296e236e9 epoll: fix epoll'... |
1627 1628 1629 1630 1631 1632 |
* 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); |
eea1d5859 epoll: use RCU to... |
1633 |
ep_pm_stay_awake(epi); |
296e236e9 epoll: fix epoll'... |
1634 1635 1636 |
} } } |
5071f97ec epoll: fix epoll'... |
1637 1638 1639 |
return eventcnt; } |
d47de16c7 fix epoll single ... |
1640 |
|
296e236e9 epoll: fix epoll'... |
1641 1642 |
static int ep_send_events(struct eventpoll *ep, struct epoll_event __user *events, int maxevents) |
5071f97ec epoll: fix epoll'... |
1643 1644 |
{ struct ep_send_events_data esed; |
1da177e4c Linux-2.6.12-rc2 |
1645 |
|
5071f97ec epoll: fix epoll'... |
1646 1647 |
esed.maxevents = maxevents; esed.events = events; |
6192bd536 epoll: optimizati... |
1648 |
|
67347fe4e epoll: do not tak... |
1649 |
return ep_scan_ready_list(ep, ep_send_events_proc, &esed, 0, false); |
1da177e4c Linux-2.6.12-rc2 |
1650 |
} |
766b9f928 fs: poll/select/r... |
1651 |
static inline struct timespec64 ep_set_mstimeout(long ms) |
0781b909b epoll: epoll_wait... |
1652 |
{ |
766b9f928 fs: poll/select/r... |
1653 |
struct timespec64 now, ts = { |
0781b909b epoll: epoll_wait... |
1654 1655 1656 |
.tv_sec = ms / MSEC_PER_SEC, .tv_nsec = NSEC_PER_MSEC * (ms % MSEC_PER_SEC), }; |
766b9f928 fs: poll/select/r... |
1657 1658 |
ktime_get_ts64(&now); return timespec64_add_safe(now, ts); |
0781b909b epoll: epoll_wait... |
1659 |
} |
f4d93ad74 epoll: fix compil... |
1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 |
/** * 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 |
1677 1678 1679 |
static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events, int maxevents, long timeout) { |
f4d93ad74 epoll: fix compil... |
1680 |
int res = 0, eavail, timed_out = 0; |
1da177e4c Linux-2.6.12-rc2 |
1681 |
unsigned long flags; |
da8b44d5a timer: convert ti... |
1682 |
u64 slack = 0; |
ac6424b98 sched/wait: Renam... |
1683 |
wait_queue_entry_t wait; |
95aac7b1c epoll: make epoll... |
1684 1685 1686 |
ktime_t expires, *to = NULL; if (timeout > 0) { |
766b9f928 fs: poll/select/r... |
1687 |
struct timespec64 end_time = ep_set_mstimeout(timeout); |
0781b909b epoll: epoll_wait... |
1688 |
|
95aac7b1c epoll: make epoll... |
1689 1690 |
slack = select_estimate_accuracy(&end_time); to = &expires; |
766b9f928 fs: poll/select/r... |
1691 |
*to = timespec64_to_ktime(end_time); |
95aac7b1c epoll: make epoll... |
1692 |
} else if (timeout == 0) { |
f4d93ad74 epoll: fix compil... |
1693 1694 1695 1696 |
/* * Avoid the unnecessary trip to the wait queue loop, if the * caller specified a non blocking operation. */ |
95aac7b1c epoll: make epoll... |
1697 |
timed_out = 1; |
f4d93ad74 epoll: fix compil... |
1698 1699 |
spin_lock_irqsave(&ep->lock, flags); goto check_events; |
95aac7b1c epoll: make epoll... |
1700 |
} |
1da177e4c Linux-2.6.12-rc2 |
1701 |
|
f4d93ad74 epoll: fix compil... |
1702 |
fetch_events: |
bf3b9f637 epoll: Add busy p... |
1703 1704 1705 |
if (!ep_events_available(ep)) ep_busy_loop(ep, timed_out); |
c7ea76302 epoll locks chang... |
1706 |
spin_lock_irqsave(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1707 |
|
3fb0e584a epoll: move ready... |
1708 |
if (!ep_events_available(ep)) { |
1da177e4c Linux-2.6.12-rc2 |
1709 |
/* |
bf3b9f637 epoll: Add busy p... |
1710 1711 1712 1713 1714 1715 1716 |
* 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); /* |
1da177e4c Linux-2.6.12-rc2 |
1717 1718 1719 1720 1721 |
* We don't have any available event to return to the caller. * We need to sleep here, and we will be wake up by * ep_poll_callback() when events will become available. */ init_waitqueue_entry(&wait, current); |
a93d2f174 sched, wait: Use ... |
1722 |
__add_wait_queue_exclusive(&ep->wq, &wait); |
1da177e4c Linux-2.6.12-rc2 |
1723 1724 1725 1726 1727 1728 1729 1730 |
for (;;) { /* * We don't want to sleep if the ep_poll_callback() sends us * a wakeup in between. That's why we set the task state * to TASK_INTERRUPTIBLE before doing the checks. */ set_current_state(TASK_INTERRUPTIBLE); |
c257a340e fs, epoll: short ... |
1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 |
/* * Always short-circuit for fatal signals to allow * threads to make a timely exit without the chance of * finding more events available and fetching * repeatedly. */ if (fatal_signal_pending(current)) { res = -EINTR; break; } |
3fb0e584a epoll: move ready... |
1741 |
if (ep_events_available(ep) || timed_out) |
1da177e4c Linux-2.6.12-rc2 |
1742 1743 1744 1745 1746 |
break; if (signal_pending(current)) { res = -EINTR; break; } |
c7ea76302 epoll locks chang... |
1747 |
spin_unlock_irqrestore(&ep->lock, flags); |
c511851de Revert "epoll: us... |
1748 |
if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS)) |
95aac7b1c epoll: make epoll... |
1749 |
timed_out = 1; |
c7ea76302 epoll locks chang... |
1750 |
spin_lock_irqsave(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1751 |
} |
1da177e4c Linux-2.6.12-rc2 |
1752 |
|
4d5755b14 epoll: optimize s... |
1753 1754 |
__remove_wait_queue(&ep->wq, &wait); __set_current_state(TASK_RUNNING); |
1da177e4c Linux-2.6.12-rc2 |
1755 |
} |
f4d93ad74 epoll: fix compil... |
1756 |
check_events: |
1da177e4c Linux-2.6.12-rc2 |
1757 |
/* Is it worth to try to dig for events ? */ |
3fb0e584a epoll: move ready... |
1758 |
eavail = ep_events_available(ep); |
1da177e4c Linux-2.6.12-rc2 |
1759 |
|
c7ea76302 epoll locks chang... |
1760 |
spin_unlock_irqrestore(&ep->lock, flags); |
1da177e4c Linux-2.6.12-rc2 |
1761 1762 1763 1764 1765 1766 1767 |
/* * 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... |
1768 |
!(res = ep_send_events(ep, events, maxevents)) && !timed_out) |
f4d93ad74 epoll: fix compil... |
1769 |
goto fetch_events; |
1da177e4c Linux-2.6.12-rc2 |
1770 1771 1772 |
return res; } |
22bacca48 epoll: prevent cr... |
1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 |
/** * 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 |
1793 |
struct eventpoll *ep_tovisit; |
22bacca48 epoll: prevent cr... |
1794 1795 |
struct rb_node *rbp; struct epitem *epi; |
d8805e633 epoll: fix spurio... |
1796 |
mutex_lock_nested(&ep->mtx, call_nests + 1); |
28d82dc1c epoll: limit paths |
1797 1798 |
ep->visited = 1; list_add(&ep->visited_list_link, &visited_list); |
b2ac2ea62 fs/epoll: use fas... |
1799 |
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) { |
22bacca48 epoll: prevent cr... |
1800 1801 |
epi = rb_entry(rbp, struct epitem, rbn); if (unlikely(is_file_epoll(epi->ffd.file))) { |
28d82dc1c epoll: limit paths |
1802 1803 1804 |
ep_tovisit = epi->ffd.file->private_data; if (ep_tovisit->visited) continue; |
22bacca48 epoll: prevent cr... |
1805 |
error = ep_call_nested(&poll_loop_ncalls, EP_MAX_NESTS, |
28d82dc1c epoll: limit paths |
1806 1807 |
ep_loop_check_proc, epi->ffd.file, ep_tovisit, current); |
22bacca48 epoll: prevent cr... |
1808 1809 |
if (error != 0) break; |
28d82dc1c epoll: limit paths |
1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 |
} 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(). */ if (list_empty(&epi->ffd.file->f_tfile_llink)) list_add(&epi->ffd.file->f_tfile_llink, &tfile_check_list); |
22bacca48 epoll: prevent cr... |
1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 |
} } 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) { |
28d82dc1c epoll: limit paths |
1842 1843 1844 1845 |
int ret; struct eventpoll *ep_cur, *ep_next; ret = ep_call_nested(&poll_loop_ncalls, EP_MAX_NESTS, |
22bacca48 epoll: prevent cr... |
1846 |
ep_loop_check_proc, file, ep, current); |
28d82dc1c epoll: limit paths |
1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 |
/* clear visited list */ list_for_each_entry_safe(ep_cur, ep_next, &visited_list, visited_list_link) { ep_cur->visited = 0; list_del(&ep_cur->visited_list_link); } return ret; } 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); } INIT_LIST_HEAD(&tfile_check_list); |
22bacca48 epoll: prevent cr... |
1867 |
} |
7699acd13 epoll cleanups: e... |
1868 |
/* |
523723bb5 fs/eventpoll.c: f... |
1869 |
* Open an eventpoll file descriptor. |
7699acd13 epoll cleanups: e... |
1870 |
*/ |
5a8a82b1d [CVE-2009-0029] S... |
1871 |
SYSCALL_DEFINE1(epoll_create1, int, flags) |
7699acd13 epoll cleanups: e... |
1872 |
{ |
28d82dc1c epoll: limit paths |
1873 |
int error, fd; |
bb57c3edc epoll: remove deb... |
1874 |
struct eventpoll *ep = NULL; |
28d82dc1c epoll: limit paths |
1875 |
struct file *file; |
7699acd13 epoll cleanups: e... |
1876 |
|
e38b36f32 flag parameters: ... |
1877 1878 |
/* Check the EPOLL_* constant for consistency. */ BUILD_BUG_ON(EPOLL_CLOEXEC != O_CLOEXEC); |
296e236e9 epoll: fix epoll'... |
1879 1880 |
if (flags & ~EPOLL_CLOEXEC) return -EINVAL; |
7699acd13 epoll cleanups: e... |
1881 |
/* |
bb57c3edc epoll: remove deb... |
1882 |
* Create the internal data structure ("struct eventpoll"). |
7699acd13 epoll cleanups: e... |
1883 |
*/ |
9fe5ad9c8 flag parameters a... |
1884 |
error = ep_alloc(&ep); |
bb57c3edc epoll: remove deb... |
1885 1886 |
if (error < 0) return error; |
7699acd13 epoll cleanups: e... |
1887 1888 |
/* * Creates all the items needed to setup an eventpoll file. That is, |
2030a42ce [PATCH] sanitize ... |
1889 |
* a file structure and a free file descriptor. |
7699acd13 epoll cleanups: e... |
1890 |
*/ |
28d82dc1c epoll: limit paths |
1891 1892 1893 1894 1895 1896 |
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... |
1897 |
O_RDWR | (flags & O_CLOEXEC)); |
28d82dc1c epoll: limit paths |
1898 1899 1900 1901 |
if (IS_ERR(file)) { error = PTR_ERR(file); goto out_free_fd; } |
28d82dc1c epoll: limit paths |
1902 |
ep->file = file; |
98022748f eventpoll: use-af... |
1903 |
fd_install(fd, file); |
28d82dc1c epoll: limit paths |
1904 1905 1906 1907 1908 1909 |
return fd; out_free_fd: put_unused_fd(fd); out_free_ep: ep_free(ep); |
bb57c3edc epoll: remove deb... |
1910 |
return error; |
7699acd13 epoll cleanups: e... |
1911 |
} |
5a8a82b1d [CVE-2009-0029] S... |
1912 |
SYSCALL_DEFINE1(epoll_create, int, size) |
a0998b50c flag parameters: ... |
1913 |
{ |
bfe3891a5 epoll: fix size c... |
1914 |
if (size <= 0) |
9fe5ad9c8 flag parameters a... |
1915 1916 1917 |
return -EINVAL; return sys_epoll_create1(0); |
a0998b50c flag parameters: ... |
1918 |
} |
7699acd13 epoll cleanups: e... |
1919 1920 1921 |
/* * The following function implements the controller interface for * the eventpoll file that enables the insertion/removal/change of |
67647d0fb epoll: fix some c... |
1922 |
* file descriptors inside the interest set. |
7699acd13 epoll cleanups: e... |
1923 |
*/ |
5a8a82b1d [CVE-2009-0029] S... |
1924 1925 |
SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd, struct epoll_event __user *, event) |
7699acd13 epoll cleanups: e... |
1926 1927 |
{ int error; |
67347fe4e epoll: do not tak... |
1928 |
int full_check = 0; |
7e3fb5842 switch epoll_ctl(... |
1929 |
struct fd f, tf; |
7699acd13 epoll cleanups: e... |
1930 1931 1932 |
struct eventpoll *ep; struct epitem *epi; struct epoll_event epds; |
67347fe4e epoll: do not tak... |
1933 |
struct eventpoll *tep = NULL; |
7699acd13 epoll cleanups: e... |
1934 |
|
7699acd13 epoll cleanups: e... |
1935 1936 1937 1938 |
error = -EFAULT; if (ep_op_has_event(op) && copy_from_user(&epds, event, sizeof(struct epoll_event))) goto error_return; |
7699acd13 epoll cleanups: e... |
1939 |
error = -EBADF; |
7e3fb5842 switch epoll_ctl(... |
1940 1941 |
f = fdget(epfd); if (!f.file) |
7699acd13 epoll cleanups: e... |
1942 1943 1944 |
goto error_return; /* Get the "struct file *" for the target file */ |
7e3fb5842 switch epoll_ctl(... |
1945 1946 |
tf = fdget(fd); if (!tf.file) |
7699acd13 epoll cleanups: e... |
1947 1948 1949 1950 |
goto error_fput; /* The target file descriptor must support poll */ error = -EPERM; |
72c2d5319 file->f_op is nev... |
1951 |
if (!tf.file->f_op->poll) |
7699acd13 epoll cleanups: e... |
1952 |
goto error_tgt_fput; |
4d7e30d98 epoll: Add a flag... |
1953 |
/* Check if EPOLLWAKEUP is allowed */ |
c680e41b3 eventpoll: fix un... |
1954 1955 |
if (ep_op_has_event(op)) ep_take_care_of_epollwakeup(&epds); |
4d7e30d98 epoll: Add a flag... |
1956 |
|
7699acd13 epoll cleanups: e... |
1957 1958 1959 1960 1961 1962 |
/* * 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(... |
1963 |
if (f.file == tf.file || !is_file_epoll(f.file)) |
7699acd13 epoll cleanups: e... |
1964 1965 1966 |
goto error_tgt_fput; /* |
df0108c5d epoll: add EPOLLE... |
1967 1968 1969 1970 |
* 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. */ |
c857ab640 fs,eventpoll: don... |
1971 |
if (ep_op_has_event(op) && (epds.events & EPOLLEXCLUSIVE)) { |
b6a515c8a epoll: restrict E... |
1972 1973 1974 1975 1976 1977 |
if (op == EPOLL_CTL_MOD) goto error_tgt_fput; if (op == EPOLL_CTL_ADD && (is_file_epoll(tf.file) || (epds.events & ~EPOLLEXCLUSIVE_OK_BITS))) goto error_tgt_fput; } |
df0108c5d epoll: add EPOLLE... |
1978 1979 |
/* |
7699acd13 epoll cleanups: e... |
1980 1981 1982 |
* At this point it is safe to assume that the "private_data" contains * our own data structure. */ |
7e3fb5842 switch epoll_ctl(... |
1983 |
ep = f.file->private_data; |
7699acd13 epoll cleanups: e... |
1984 |
|
22bacca48 epoll: prevent cr... |
1985 1986 1987 |
/* * 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 |
1988 1989 1990 1991 |
* 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... |
1992 |
* |
67347fe4e epoll: do not tak... |
1993 1994 1995 1996 1997 1998 |
* 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... |
1999 |
*/ |
67347fe4e epoll: do not tak... |
2000 |
mutex_lock_nested(&ep->mtx, 0); |
28d82dc1c epoll: limit paths |
2001 |
if (op == EPOLL_CTL_ADD) { |
67347fe4e epoll: do not tak... |
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 |
if (!list_empty(&f.file->f_ep_links) || is_file_epoll(tf.file)) { full_check = 1; mutex_unlock(&ep->mtx); mutex_lock(&epmutex); if (is_file_epoll(tf.file)) { error = -ELOOP; if (ep_loop_check(ep, tf.file) != 0) { clear_tfile_check_list(); goto error_tgt_fput; } } else list_add(&tf.file->f_tfile_llink, &tfile_check_list); mutex_lock_nested(&ep->mtx, 0); if (is_file_epoll(tf.file)) { tep = tf.file->private_data; mutex_lock_nested(&tep->mtx, 1); |
13d518074 epoll: clear the ... |
2020 |
} |
67347fe4e epoll: do not tak... |
2021 2022 |
} } |
7699acd13 epoll cleanups: e... |
2023 |
|
67647d0fb epoll: fix some c... |
2024 2025 2026 2027 2028 |
/* * 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(... |
2029 |
epi = ep_find(ep, tf.file, fd); |
7699acd13 epoll cleanups: e... |
2030 2031 2032 2033 2034 2035 |
error = -EINVAL; switch (op) { case EPOLL_CTL_ADD: if (!epi) { epds.events |= POLLERR | POLLHUP; |
67347fe4e epoll: do not tak... |
2036 |
error = ep_insert(ep, &epds, tf.file, fd, full_check); |
7699acd13 epoll cleanups: e... |
2037 2038 |
} else error = -EEXIST; |
67347fe4e epoll: do not tak... |
2039 2040 |
if (full_check) clear_tfile_check_list(); |
7699acd13 epoll cleanups: e... |
2041 2042 2043 2044 2045 2046 2047 2048 2049 |
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... |
2050 2051 2052 2053 |
if (!(epi->event.events & EPOLLEXCLUSIVE)) { epds.events |= POLLERR | POLLHUP; error = ep_modify(ep, epi, &epds); } |
7699acd13 epoll cleanups: e... |
2054 2055 2056 2057 |
} else error = -ENOENT; break; } |
67347fe4e epoll: do not tak... |
2058 2059 |
if (tep != NULL) mutex_unlock(&tep->mtx); |
d47de16c7 fix epoll single ... |
2060 |
mutex_unlock(&ep->mtx); |
7699acd13 epoll cleanups: e... |
2061 2062 |
error_tgt_fput: |
67347fe4e epoll: do not tak... |
2063 |
if (full_check) |
22bacca48 epoll: prevent cr... |
2064 |
mutex_unlock(&epmutex); |
7e3fb5842 switch epoll_ctl(... |
2065 |
fdput(tf); |
7699acd13 epoll cleanups: e... |
2066 |
error_fput: |
7e3fb5842 switch epoll_ctl(... |
2067 |
fdput(f); |
7699acd13 epoll cleanups: e... |
2068 |
error_return: |
7699acd13 epoll cleanups: e... |
2069 2070 2071 2072 2073 2074 2075 2076 |
return error; } /* * Implement the event wait interface for the eventpoll file. It is the kernel * part of the user space epoll_wait(2). */ |
5a8a82b1d [CVE-2009-0029] S... |
2077 2078 |
SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events, int, maxevents, int, timeout) |
7699acd13 epoll cleanups: e... |
2079 |
{ |
2903ff019 switch simple cas... |
2080 2081 |
int error; struct fd f; |
7699acd13 epoll cleanups: e... |
2082 |
struct eventpoll *ep; |
7699acd13 epoll cleanups: e... |
2083 2084 2085 2086 2087 |
/* 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 */ |
2903ff019 switch simple cas... |
2088 2089 |
if (!access_ok(VERIFY_WRITE, events, maxevents * sizeof(struct epoll_event))) return -EFAULT; |
7699acd13 epoll cleanups: e... |
2090 2091 |
/* Get the "struct file *" for the eventpoll file */ |
2903ff019 switch simple cas... |
2092 2093 2094 |
f = fdget(epfd); if (!f.file) return -EBADF; |
7699acd13 epoll cleanups: e... |
2095 2096 2097 2098 2099 2100 |
/* * 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... |
2101 |
if (!is_file_epoll(f.file)) |
7699acd13 epoll cleanups: e... |
2102 2103 2104 2105 2106 2107 |
goto error_fput; /* * At this point it is safe to assume that the "private_data" contains * our own data structure. */ |
2903ff019 switch simple cas... |
2108 |
ep = f.file->private_data; |
7699acd13 epoll cleanups: e... |
2109 2110 2111 2112 2113 |
/* Time to fish for events ... */ error = ep_poll(ep, events, maxevents, timeout); error_fput: |
2903ff019 switch simple cas... |
2114 |
fdput(f); |
7699acd13 epoll cleanups: e... |
2115 2116 |
return error; } |
7699acd13 epoll cleanups: e... |
2117 2118 2119 2120 |
/* * 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... |
2121 2122 2123 |
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... |
2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 |
{ int error; sigset_t ksigmask, sigsaved; /* * If the caller wants a certain signal mask to be set during the wait, * we apply it here. */ if (sigmask) { if (sigsetsize != sizeof(sigset_t)) return -EINVAL; if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) return -EFAULT; |
77d559180 signals: eventpol... |
2137 2138 |
sigsaved = current->blocked; set_current_blocked(&ksigmask); |
7699acd13 epoll cleanups: e... |
2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 |
} error = sys_epoll_wait(epfd, events, maxevents, timeout); /* * If we changed the signal mask, we need to restore the original one. * In case we've got a signal while waiting, we do not restore the * signal mask yet, and we allow do_signal() to deliver the signal on * the way back to userspace, before the signal mask is restored. */ if (sigmask) { if (error == -EINTR) { memcpy(¤t->saved_sigmask, &sigsaved, |
c7ea76302 epoll locks chang... |
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sizeof(sigsaved)); |
4e4c22c71 signals: add set_... |
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set_restore_sigmask(); |
7699acd13 epoll cleanups: e... |
2154 |
} else |
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set_current_blocked(&sigsaved); |
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} return error; } |
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#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; compat_sigset_t csigmask; sigset_t ksigmask, sigsaved; /* * If the caller wants a certain signal mask to be set during the wait, * we apply it here. */ if (sigmask) { if (sigsetsize != sizeof(compat_sigset_t)) return -EINVAL; if (copy_from_user(&csigmask, sigmask, sizeof(csigmask))) return -EFAULT; sigset_from_compat(&ksigmask, &csigmask); |
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sigsaved = current->blocked; set_current_blocked(&ksigmask); |
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} err = sys_epoll_wait(epfd, events, maxevents, timeout); /* * If we changed the signal mask, we need to restore the original one. * In case we've got a signal while waiting, we do not restore the * signal mask yet, and we allow do_signal() to deliver the signal on * the way back to userspace, before the signal mask is restored. */ if (sigmask) { if (err == -EINTR) { memcpy(¤t->saved_sigmask, &sigsaved, sizeof(sigsaved)); set_restore_sigmask(); } else |
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set_current_blocked(&sigsaved); |
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} return err; } #endif |
1da177e4c Linux-2.6.12-rc2 |
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static int __init eventpoll_init(void) { |
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struct sysinfo si; si_meminfo(&si); |
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/* * Allows top 4% of lomem to be allocated for epoll watches (per user). */ max_user_watches = (((si.totalram - si.totalhigh) / 25) << PAGE_SHIFT) / |
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EP_ITEM_COST; |
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BUG_ON(max_user_watches < 0); |
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2216 |
|
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/* * Initialize the structure used to perform epoll file descriptor * inclusion loops checks. */ ep_nested_calls_init(&poll_loop_ncalls); |
1da177e4c Linux-2.6.12-rc2 |
2222 |
/* Initialize the structure used to perform safe poll wait head wake ups */ |
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ep_nested_calls_init(&poll_safewake_ncalls); /* Initialize the structure used to perform file's f_op->poll() calls */ ep_nested_calls_init(&poll_readywalk_ncalls); |
1da177e4c Linux-2.6.12-rc2 |
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|
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/* * 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 |
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/* Allocates slab cache used to allocate "struct epitem" items */ epi_cache = kmem_cache_create("eventpoll_epi", sizeof(struct epitem), |
bb57c3edc epoll: remove deb... |
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0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); |
1da177e4c Linux-2.6.12-rc2 |
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/* Allocates slab cache used to allocate "struct eppoll_entry" */ pwq_cache = kmem_cache_create("eventpoll_pwq", |
bb57c3edc epoll: remove deb... |
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sizeof(struct eppoll_entry), 0, SLAB_PANIC, NULL); |
1da177e4c Linux-2.6.12-rc2 |
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|
1da177e4c Linux-2.6.12-rc2 |
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return 0; |
1da177e4c Linux-2.6.12-rc2 |
2242 |
} |
cea692418 epoll cleanups: e... |
2243 |
fs_initcall(eventpoll_init); |