/*
- * fs/eventpoll.c ( Efficent event polling implementation )
- * Copyright (C) 2001,...,2006 Davide Libenzi
+ * fs/eventpoll.c (Efficent event polling implementation)
+ * Copyright (C) 2001,...,2007 Davide Libenzi
*
* 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
* There are three level of locking required by epoll :
*
* 1) epmutex (mutex)
- * 2) ep->mtx (mutes)
- * 3) ep->lock (rw_lock)
+ * 2) ep->mtx (mutex)
+ * 3) ep->lock (spinlock)
*
* The acquire order is the one listed above, from 1 to 3.
* We need a spinlock (ep->lock) because we manipulate objects
#define EP_UNACTIVE_PTR ((void *) -1L)
+#define EP_ITEM_COST (sizeof(struct epitem) + sizeof(struct eppoll_entry))
+
struct epoll_filefd {
struct file *file;
int fd;
* have an entry of this type linked to the "rbr" RB tree.
*/
struct epitem {
- /* RB-Tree node used to link this structure to the eventpoll rb-tree */
+ /* RB tree node used to link this structure to the eventpoll RB tree */
struct rb_node rbn;
/* List header used to link this structure to the eventpoll ready list */
struct list_head rdllink;
+ /*
+ * Works together "struct eventpoll"->ovflist in keeping the
+ * single linked chain of items.
+ */
+ struct epitem *next;
+
/* The file descriptor information this item refers to */
struct epoll_filefd ffd;
/* The "container" of this item */
struct eventpoll *ep;
- /* The structure that describe the interested events and the source fd */
- struct epoll_event event;
-
- /*
- * Used to keep track of the usage count of the structure. This avoids
- * that the structure will desappear from underneath our processing.
- */
- atomic_t usecnt;
-
/* List header used to link this item to the "struct file" items list */
struct list_head fllink;
- /*
- * Works together "struct eventpoll"->ovflist in keeping the
- * single linked chain of items.
- */
- struct epitem *next;
+ /* The structure that describe the interested events and the source fd */
+ struct epoll_event event;
};
/*
*/
struct eventpoll {
/* Protect the this structure access */
- rwlock_t lock;
+ spinlock_t lock;
/*
* This mutex is used to ensure that files are not removed
/* List of ready file descriptors */
struct list_head rdllist;
- /* RB-Tree root used to store monitored fd structs */
+ /* RB tree root used to store monitored fd structs */
struct rb_root rbr;
/*
* holding ->lock.
*/
struct epitem *ovflist;
+
+ /* The user that created the eventpoll descriptor */
+ struct user_struct *user;
};
/* Wait structure used by the poll hooks */
};
/*
+ * Configuration options available inside /proc/sys/fs/epoll/
+ */
+/* Maximum number of epoll watched descriptors, per user */
+static int max_user_watches __read_mostly;
+
+/*
* This mutex is used to serialize ep_free() and eventpoll_release_file().
*/
-static struct mutex epmutex;
+static DEFINE_MUTEX(epmutex);
/* Safe wake up implementation */
static struct poll_safewake psw;
/* Slab cache used to allocate "struct eppoll_entry" */
static struct kmem_cache *pwq_cache __read_mostly;
+#ifdef CONFIG_SYSCTL
+
+#include <linux/sysctl.h>
+
+static int zero;
+
+ctl_table epoll_table[] = {
+ {
+ .procname = "max_user_watches",
+ .data = &max_user_watches,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_minmax,
+ .extra1 = &zero,
+ },
+ { .ctl_name = 0 }
+};
+#endif /* CONFIG_SYSCTL */
+
-/* Setup the structure that is used as key for the rb-tree */
+/* Setup the structure that is used as key for the RB tree */
static inline void ep_set_ffd(struct epoll_filefd *ffd,
struct file *file, int fd)
{
ffd->fd = fd;
}
-/* Compare rb-tree keys */
+/* Compare RB tree keys */
static inline int ep_cmp_ffd(struct epoll_filefd *p1,
struct epoll_filefd *p2)
{
(p1->file < p2->file ? -1 : p1->fd - p2->fd));
}
-/* Special initialization for the rb-tree node to detect linkage */
-static inline void ep_rb_initnode(struct rb_node *n)
-{
- rb_set_parent(n, n);
-}
-
-/* Removes a node from the rb-tree and marks it for a fast is-linked check */
-static inline void ep_rb_erase(struct rb_node *n, struct rb_root *r)
-{
- rb_erase(n, r);
- rb_set_parent(n, n);
-}
-
-/* Fast check to verify that the item is linked to the main rb-tree */
-static inline int ep_rb_linked(struct rb_node *n)
-{
- return rb_parent(n) != n;
-}
-
/* Tells us if the item is currently linked */
static inline int ep_is_linked(struct list_head *p)
{
}
/* Get the "struct epitem" from a wait queue pointer */
-static inline struct epitem * ep_item_from_wait(wait_queue_t *p)
+static inline struct epitem *ep_item_from_wait(wait_queue_t *p)
{
return container_of(p, struct eppoll_entry, wait)->base;
}
/* Get the "struct epitem" from an epoll queue wrapper */
-static inline struct epitem * ep_item_from_epqueue(poll_table *p)
+static inline struct epitem *ep_item_from_epqueue(poll_table *p)
{
return container_of(p, struct ep_pqueue, pt)->epi;
}
int wake_nests = 0;
unsigned long flags;
struct task_struct *this_task = current;
- struct list_head *lsthead = &psw->wake_task_list, *lnk;
+ struct list_head *lsthead = &psw->wake_task_list;
struct wake_task_node *tncur;
struct wake_task_node tnode;
spin_lock_irqsave(&psw->lock, flags);
/* Try to see if the current task is already inside this wakeup call */
- list_for_each(lnk, lsthead) {
- tncur = list_entry(lnk, struct wake_task_node, llink);
+ list_for_each_entry(tncur, lsthead, llink) {
if (tncur->wq == wq ||
(tncur->task == this_task && ++wake_nests > EP_MAX_POLLWAKE_NESTS)) {
spin_unlock_irqrestore(&psw->lock, flags);
/* Do really wake up now */
- wake_up(wq);
+ wake_up_nested(wq, 1 + wake_nests);
/* Remove the current task from the list */
spin_lock_irqsave(&psw->lock, flags);
}
/*
- * Unlink the "struct epitem" from all places it might have been hooked up.
- * This function must be called with write IRQ lock on "ep->lock".
- */
-static int ep_unlink(struct eventpoll *ep, struct epitem *epi)
-{
- int error;
-
- /*
- * It can happen that this one is called for an item already unlinked.
- * The check protect us from doing a double unlink ( crash ).
- */
- error = -ENOENT;
- if (!ep_rb_linked(&epi->rbn))
- goto error_return;
-
- /*
- * Clear the event mask for the unlinked item. This will avoid item
- * notifications to be sent after the unlink operation from inside
- * the kernel->userspace event transfer loop.
- */
- epi->event.events = 0;
-
- /*
- * At this point is safe to do the job, unlink the item from our rb-tree.
- * This operation togheter with the above check closes the door to
- * double unlinks.
- */
- ep_rb_erase(&epi->rbn, &ep->rbr);
-
- /*
- * If the item we are going to remove is inside the ready file descriptors
- * we want to remove it from this list to avoid stale events.
- */
- if (ep_is_linked(&epi->rdllink))
- list_del_init(&epi->rdllink);
-
- error = 0;
-error_return:
-
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: ep_unlink(%p, %p) = %d\n",
- current, ep, epi->ffd.file, error));
-
- return error;
-}
-
-/*
- * Increment the usage count of the "struct epitem" making it sure
- * that the user will have a valid pointer to reference.
- */
-static void ep_use_epitem(struct epitem *epi)
-{
- atomic_inc(&epi->usecnt);
-}
-
-/*
- * Decrement ( release ) the usage count by signaling that the user
- * has finished using the structure. It might lead to freeing the
- * structure itself if the count goes to zero.
- */
-static void ep_release_epitem(struct epitem *epi)
-{
- if (atomic_dec_and_test(&epi->usecnt))
- kmem_cache_free(epi_cache, epi);
-}
-
-/*
* Removes a "struct epitem" from the eventpoll RB tree and deallocates
- * all the associated resources.
+ * all the associated resources. Must be called with "mtx" held.
*/
static int ep_remove(struct eventpoll *ep, struct epitem *epi)
{
- int error;
unsigned long flags;
struct file *file = epi->ffd.file;
list_del_init(&epi->fllink);
spin_unlock(&file->f_ep_lock);
- /* We need to acquire the write IRQ lock before calling ep_unlink() */
- write_lock_irqsave(&ep->lock, flags);
-
- /* Really unlink the item from the RB tree */
- error = ep_unlink(ep, epi);
+ rb_erase(&epi->rbn, &ep->rbr);
- write_unlock_irqrestore(&ep->lock, flags);
-
- if (error)
- goto error_return;
+ spin_lock_irqsave(&ep->lock, flags);
+ if (ep_is_linked(&epi->rdllink))
+ list_del_init(&epi->rdllink);
+ spin_unlock_irqrestore(&ep->lock, flags);
/* At this point it is safe to free the eventpoll item */
- ep_release_epitem(epi);
+ kmem_cache_free(epi_cache, epi);
- error = 0;
-error_return:
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: ep_remove(%p, %p) = %d\n",
- current, ep, file, error));
+ atomic_dec(&ep->user->epoll_watches);
- return error;
+ DNPRINTK(3, (KERN_INFO "[%p] eventpoll: ep_remove(%p, %p)\n",
+ current, ep, file));
+
+ return 0;
}
static void ep_free(struct eventpoll *ep)
* holding "epmutex" we can be sure that no file cleanup code will hit
* us during this operation. So we can avoid the lock on "ep->lock".
*/
- while ((rbp = rb_first(&ep->rbr)) != 0) {
+ while ((rbp = rb_first(&ep->rbr)) != NULL) {
epi = rb_entry(rbp, struct epitem, rbn);
ep_remove(ep, epi);
}
mutex_unlock(&epmutex);
-
mutex_destroy(&ep->mtx);
+ free_uid(ep->user);
+ kfree(ep);
}
static int ep_eventpoll_release(struct inode *inode, struct file *file)
{
struct eventpoll *ep = file->private_data;
- if (ep) {
+ if (ep)
ep_free(ep);
- kfree(ep);
- }
DNPRINTK(3, (KERN_INFO "[%p] eventpoll: close() ep=%p\n", current, ep));
return 0;
poll_wait(file, &ep->poll_wait, wait);
/* Check our condition */
- read_lock_irqsave(&ep->lock, flags);
+ spin_lock_irqsave(&ep->lock, flags);
if (!list_empty(&ep->rdllist))
pollflags = POLLIN | POLLRDNORM;
- read_unlock_irqrestore(&ep->lock, flags);
+ spin_unlock_irqrestore(&ep->lock, flags);
return pollflags;
}
* We don't want to get "file->f_ep_lock" because it is not
* necessary. It is not necessary because we're in the "struct file"
* cleanup path, and this means that noone is using this file anymore.
+ * So, for example, epoll_ctl() cannot hit here sicne if we reach this
+ * point, the file counter already went to zero and fget() would fail.
* The only hit might come from ep_free() but by holding the mutex
* will correctly serialize the operation. We do need to acquire
* "ep->mtx" after "epmutex" because ep_remove() requires it when called
static int ep_alloc(struct eventpoll **pep)
{
- struct eventpoll *ep = kzalloc(sizeof(*ep), GFP_KERNEL);
+ int error;
+ struct user_struct *user;
+ struct eventpoll *ep;
- if (!ep)
- return -ENOMEM;
+ user = get_current_user();
+ error = -ENOMEM;
+ ep = kzalloc(sizeof(*ep), GFP_KERNEL);
+ if (unlikely(!ep))
+ goto free_uid;
- rwlock_init(&ep->lock);
+ spin_lock_init(&ep->lock);
mutex_init(&ep->mtx);
init_waitqueue_head(&ep->wq);
init_waitqueue_head(&ep->poll_wait);
INIT_LIST_HEAD(&ep->rdllist);
ep->rbr = RB_ROOT;
ep->ovflist = EP_UNACTIVE_PTR;
+ ep->user = user;
*pep = ep;
DNPRINTK(3, (KERN_INFO "[%p] eventpoll: ep_alloc() ep=%p\n",
current, ep));
return 0;
+
+free_uid:
+ free_uid(user);
+ return error;
}
/*
- * Search the file inside the eventpoll tree. It add usage count to
- * the returned item, so the caller must call ep_release_epitem()
- * after finished using the "struct epitem".
+ * 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.
*/
static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd)
{
int kcmp;
- unsigned long flags;
struct rb_node *rbp;
struct epitem *epi, *epir = NULL;
struct epoll_filefd ffd;
ep_set_ffd(&ffd, file, fd);
- read_lock_irqsave(&ep->lock, flags);
for (rbp = ep->rbr.rb_node; rbp; ) {
epi = rb_entry(rbp, struct epitem, rbn);
kcmp = ep_cmp_ffd(&ffd, &epi->ffd);
else if (kcmp < 0)
rbp = rbp->rb_left;
else {
- ep_use_epitem(epi);
epir = epi;
break;
}
}
- read_unlock_irqrestore(&ep->lock, flags);
DNPRINTK(3, (KERN_INFO "[%p] eventpoll: ep_find(%p) -> %p\n",
current, file, epir));
DNPRINTK(3, (KERN_INFO "[%p] eventpoll: poll_callback(%p) epi=%p ep=%p\n",
current, epi->ffd.file, epi, ep));
- write_lock_irqsave(&ep->lock, flags);
+ spin_lock_irqsave(&ep->lock, flags);
/*
* If the event mask does not contain any poll(2) event, we consider the
* wait list.
*/
if (waitqueue_active(&ep->wq))
- __wake_up_locked(&ep->wq, TASK_UNINTERRUPTIBLE |
- TASK_INTERRUPTIBLE);
+ wake_up_locked(&ep->wq);
if (waitqueue_active(&ep->poll_wait))
pwake++;
out_unlock:
- write_unlock_irqrestore(&ep->lock, flags);
+ spin_unlock_irqrestore(&ep->lock, flags);
/* We have to call this outside the lock */
if (pwake)
rb_insert_color(&epi->rbn, &ep->rbr);
}
+/*
+ * Must be called with "mtx" held.
+ */
static int ep_insert(struct eventpoll *ep, struct epoll_event *event,
struct file *tfile, int fd)
{
struct epitem *epi;
struct ep_pqueue epq;
- error = -ENOMEM;
+ if (unlikely(atomic_read(&ep->user->epoll_watches) >=
+ max_user_watches))
+ return -ENOSPC;
if (!(epi = kmem_cache_alloc(epi_cache, GFP_KERNEL)))
- goto error_return;
+ return -ENOMEM;
/* Item initialization follow here ... */
- ep_rb_initnode(&epi->rbn);
INIT_LIST_HEAD(&epi->rdllink);
INIT_LIST_HEAD(&epi->fllink);
INIT_LIST_HEAD(&epi->pwqlist);
epi->ep = ep;
ep_set_ffd(&epi->ffd, tfile, fd);
epi->event = *event;
- atomic_set(&epi->usecnt, 1);
epi->nwait = 0;
epi->next = EP_UNACTIVE_PTR;
/*
* Attach the item to the poll hooks and get current event bits.
* We can safely use the file* here because its usage count has
- * been increased by the caller of this function.
+ * been increased by the caller of this function. Note that after
+ * this operation completes, the poll callback can start hitting
+ * the new item.
*/
revents = tfile->f_op->poll(tfile, &epq.pt);
* install process. Namely an allocation for a wait queue failed due
* high memory pressure.
*/
+ error = -ENOMEM;
if (epi->nwait < 0)
goto error_unregister;
list_add_tail(&epi->fllink, &tfile->f_ep_links);
spin_unlock(&tfile->f_ep_lock);
- /* We have to drop the new item inside our item list to keep track of it */
- write_lock_irqsave(&ep->lock, flags);
-
- /* Add the current item to the rb-tree */
+ /*
+ * Add the current item to the RB tree. All RB tree operations are
+ * protected by "mtx", and ep_insert() is called with "mtx" held.
+ */
ep_rbtree_insert(ep, epi);
+ /* We have to drop the new item inside our item list to keep track of it */
+ spin_lock_irqsave(&ep->lock, flags);
+
/* If the file is already "ready" we drop it inside the ready list */
if ((revents & event->events) && !ep_is_linked(&epi->rdllink)) {
list_add_tail(&epi->rdllink, &ep->rdllist);
/* Notify waiting tasks that events are available */
if (waitqueue_active(&ep->wq))
- __wake_up_locked(&ep->wq, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE);
+ wake_up_locked(&ep->wq);
if (waitqueue_active(&ep->poll_wait))
pwake++;
}
- write_unlock_irqrestore(&ep->lock, flags);
+ spin_unlock_irqrestore(&ep->lock, flags);
+
+ atomic_inc(&ep->user->epoll_watches);
/* We have to call this outside the lock */
if (pwake)
/*
* We need to do this because an event could have been arrived on some
- * allocated wait queue.
+ * 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.
*/
- write_lock_irqsave(&ep->lock, flags);
+ spin_lock_irqsave(&ep->lock, flags);
if (ep_is_linked(&epi->rdllink))
list_del_init(&epi->rdllink);
- write_unlock_irqrestore(&ep->lock, flags);
+ spin_unlock_irqrestore(&ep->lock, flags);
kmem_cache_free(epi_cache, epi);
-error_return:
+
return error;
}
/*
* Modify the interest event mask by dropping an event if the new mask
- * has a match in the current file status.
+ * has a match in the current file status. Must be called with "mtx" held.
*/
static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_event *event)
{
*/
revents = epi->ffd.file->f_op->poll(epi->ffd.file, NULL);
- write_lock_irqsave(&ep->lock, flags);
+ spin_lock_irqsave(&ep->lock, flags);
/* Copy the data member from inside the lock */
epi->event.data = event->data;
/*
- * If the item is not linked to the RB tree it means that it's on its
- * way toward the removal. Do nothing in this case.
+ * If the item is "hot" and it is not registered inside the ready
+ * list, push it inside.
*/
- if (ep_rb_linked(&epi->rbn)) {
- /*
- * If the item is "hot" and it is not registered inside the ready
- * list, push it inside. If the item is not "hot" and it is currently
- * registered inside the ready list, unlink it.
- */
- if (revents & event->events) {
- if (!ep_is_linked(&epi->rdllink)) {
- list_add_tail(&epi->rdllink, &ep->rdllist);
-
- /* Notify waiting tasks that events are available */
- if (waitqueue_active(&ep->wq))
- __wake_up_locked(&ep->wq, TASK_UNINTERRUPTIBLE |
- TASK_INTERRUPTIBLE);
- if (waitqueue_active(&ep->poll_wait))
- pwake++;
- }
+ if (revents & event->events) {
+ if (!ep_is_linked(&epi->rdllink)) {
+ list_add_tail(&epi->rdllink, &ep->rdllist);
+
+ /* Notify waiting tasks that events are available */
+ if (waitqueue_active(&ep->wq))
+ wake_up_locked(&ep->wq);
+ if (waitqueue_active(&ep->poll_wait))
+ pwake++;
}
}
-
- write_unlock_irqrestore(&ep->lock, flags);
+ spin_unlock_irqrestore(&ep->lock, flags);
/* We have to call this outside the lock */
if (pwake)
* have the poll callback to queue directly on ep->rdllist,
* because we are doing it in the loop below, in a lockless way.
*/
- write_lock_irqsave(&ep->lock, flags);
+ spin_lock_irqsave(&ep->lock, flags);
list_splice(&ep->rdllist, &txlist);
INIT_LIST_HEAD(&ep->rdllist);
ep->ovflist = NULL;
- write_unlock_irqrestore(&ep->lock, flags);
+ spin_unlock_irqrestore(&ep->lock, flags);
/*
* We can loop without lock because this is a task private list.
errxit:
- write_lock_irqsave(&ep->lock, flags);
+ spin_lock_irqsave(&ep->lock, flags);
/*
* During the time we spent in the loop above, some other events
* might have been queued by the poll callback. We re-insert them
- * here (in case they are not already queued, or they're one-shot).
+ * inside the main ready-list here.
*/
for (nepi = ep->ovflist; (epi = nepi) != NULL;
nepi = epi->next, epi->next = EP_UNACTIVE_PTR) {
- if (!ep_is_linked(&epi->rdllink) &&
- (epi->event.events & ~EP_PRIVATE_BITS))
+ /*
+ * If the above loop quit with errors, the epoll item might still
+ * be linked to "txlist", and the list_splice() done below will
+ * take care of those cases.
+ */
+ if (!ep_is_linked(&epi->rdllink))
list_add_tail(&epi->rdllink, &ep->rdllist);
}
/*
ep->ovflist = EP_UNACTIVE_PTR;
/*
- * In case of error in the event-send loop, we might still have items
- * inside the "txlist". We need to splice them back inside ep->rdllist.
+ * In case of error in the event-send loop, or in case the number of
+ * ready events exceeds the userspace limit, we need to splice the
+ * "txlist" back inside ep->rdllist.
*/
list_splice(&txlist, &ep->rdllist);
if (!list_empty(&ep->rdllist)) {
/*
* Wake up (if active) both the eventpoll wait list and the ->poll()
- * wait list.
+ * wait list (delayed after we release the lock).
*/
if (waitqueue_active(&ep->wq))
- __wake_up_locked(&ep->wq, TASK_UNINTERRUPTIBLE |
- TASK_INTERRUPTIBLE);
+ wake_up_locked(&ep->wq);
if (waitqueue_active(&ep->poll_wait))
pwake++;
}
- write_unlock_irqrestore(&ep->lock, flags);
+ spin_unlock_irqrestore(&ep->lock, flags);
mutex_unlock(&ep->mtx);
MAX_SCHEDULE_TIMEOUT : (timeout * HZ + 999) / 1000;
retry:
- write_lock_irqsave(&ep->lock, flags);
+ spin_lock_irqsave(&ep->lock, flags);
res = 0;
if (list_empty(&ep->rdllist)) {
break;
}
- write_unlock_irqrestore(&ep->lock, flags);
+ spin_unlock_irqrestore(&ep->lock, flags);
jtimeout = schedule_timeout(jtimeout);
- write_lock_irqsave(&ep->lock, flags);
+ spin_lock_irqsave(&ep->lock, flags);
}
__remove_wait_queue(&ep->wq, &wait);
/* Is it worth to try to dig for events ? */
eavail = !list_empty(&ep->rdllist);
- write_unlock_irqrestore(&ep->lock, flags);
+ spin_unlock_irqrestore(&ep->lock, flags);
/*
* Try to transfer events to user space. In case we get 0 events and
}
/*
- * It opens an eventpoll file descriptor by suggesting a storage of "size"
- * file descriptors. The size parameter is just an hint about how to size
- * data structures. It won't prevent the user to store more than "size"
- * file descriptors inside the epoll interface. It is the kernel part of
- * the userspace epoll_create(2).
+ * Open an eventpoll file descriptor.
*/
-asmlinkage long sys_epoll_create(int size)
+SYSCALL_DEFINE1(epoll_create1, int, flags)
{
int error, fd = -1;
struct eventpoll *ep;
- struct inode *inode;
- struct file *file;
+
+ /* Check the EPOLL_* constant for consistency. */
+ BUILD_BUG_ON(EPOLL_CLOEXEC != O_CLOEXEC);
+
+ if (flags & ~EPOLL_CLOEXEC)
+ return -EINVAL;
DNPRINTK(3, (KERN_INFO "[%p] eventpoll: sys_epoll_create(%d)\n",
- current, size));
+ current, flags));
/*
- * Sanity check on the size parameter, and create the internal data
- * structure ( "struct eventpoll" ).
+ * Create the internal data structure ( "struct eventpoll" ).
*/
- error = -EINVAL;
- if (size <= 0 || (error = ep_alloc(&ep)) != 0)
+ error = ep_alloc(&ep);
+ if (error < 0) {
+ fd = error;
goto error_return;
+ }
/*
* Creates all the items needed to setup an eventpoll file. That is,
- * a file structure, and inode and a free file descriptor.
+ * a file structure and a free file descriptor.
*/
- error = anon_inode_getfd(&fd, &inode, &file, "[eventpoll]",
- &eventpoll_fops, ep);
- if (error)
- goto error_free;
+ fd = anon_inode_getfd("[eventpoll]", &eventpoll_fops, ep,
+ flags & O_CLOEXEC);
+ if (fd < 0)
+ ep_free(ep);
+error_return:
DNPRINTK(3, (KERN_INFO "[%p] eventpoll: sys_epoll_create(%d) = %d\n",
- current, size, fd));
+ current, flags, fd));
return fd;
+}
-error_free:
- ep_free(ep);
- kfree(ep);
-error_return:
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: sys_epoll_create(%d) = %d\n",
- current, size, error));
- return error;
+SYSCALL_DEFINE1(epoll_create, int, size)
+{
+ if (size < 0)
+ return -EINVAL;
+
+ return sys_epoll_create1(0);
}
/*
* The following function implements the controller interface for
* the eventpoll file that enables the insertion/removal/change of
- * file descriptors inside the interest set. It represents
- * the kernel part of the user space epoll_ctl(2).
+ * file descriptors inside the interest set.
*/
-asmlinkage long sys_epoll_ctl(int epfd, int op, int fd,
- struct epoll_event __user *event)
+SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
+ struct epoll_event __user *, event)
{
int error;
struct file *file, *tfile;
mutex_lock(&ep->mtx);
- /* Try to lookup the file inside our RB tree */
+ /*
+ * 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.
+ */
epi = ep_find(ep, tfile, fd);
error = -EINVAL;
error = -ENOENT;
break;
}
- /*
- * The function ep_find() increments the usage count of the structure
- * so, if this is not NULL, we need to release it.
- */
- if (epi)
- ep_release_epitem(epi);
mutex_unlock(&ep->mtx);
error_tgt_fput:
* Implement the event wait interface for the eventpoll file. It is the kernel
* part of the user space epoll_wait(2).
*/
-asmlinkage long sys_epoll_wait(int epfd, struct epoll_event __user *events,
- int maxevents, int timeout)
+SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events,
+ int, maxevents, int, timeout)
{
int error;
struct file *file;
return error;
}
-#ifdef TIF_RESTORE_SIGMASK
+#ifdef HAVE_SET_RESTORE_SIGMASK
/*
* Implement the event wait interface for the eventpoll file. It is the kernel
* part of the user space epoll_pwait(2).
*/
-asmlinkage long sys_epoll_pwait(int epfd, struct epoll_event __user *events,
- int maxevents, int timeout, const sigset_t __user *sigmask,
- size_t sigsetsize)
+SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events,
+ int, maxevents, int, timeout, const sigset_t __user *, sigmask,
+ size_t, sigsetsize)
{
int error;
sigset_t ksigmask, sigsaved;
if (sigmask) {
if (error == -EINTR) {
memcpy(¤t->saved_sigmask, &sigsaved,
- sizeof(sigsaved));
- set_thread_flag(TIF_RESTORE_SIGMASK);
+ sizeof(sigsaved));
+ set_restore_sigmask();
} else
sigprocmask(SIG_SETMASK, &sigsaved, NULL);
}
return error;
}
-#endif /* #ifdef TIF_RESTORE_SIGMASK */
+#endif /* HAVE_SET_RESTORE_SIGMASK */
static int __init eventpoll_init(void)
{
- mutex_init(&epmutex);
+ struct sysinfo si;
+
+ si_meminfo(&si);
+ /*
+ * Allows top 4% of lomem to be allocated for epoll watches (per user).
+ */
+ max_user_watches = (((si.totalram - si.totalhigh) / 25) << PAGE_SHIFT) /
+ EP_ITEM_COST;
/* Initialize the structure used to perform safe poll wait head wake ups */
ep_poll_safewake_init(&psw);
/* Allocates slab cache used to allocate "struct epitem" items */
epi_cache = kmem_cache_create("eventpoll_epi", sizeof(struct epitem),
0, SLAB_HWCACHE_ALIGN|EPI_SLAB_DEBUG|SLAB_PANIC,
- NULL, NULL);
+ NULL);
/* Allocates slab cache used to allocate "struct eppoll_entry" */
pwq_cache = kmem_cache_create("eventpoll_pwq",
sizeof(struct eppoll_entry), 0,
- EPI_SLAB_DEBUG|SLAB_PANIC, NULL, NULL);
+ EPI_SLAB_DEBUG|SLAB_PANIC, NULL);
return 0;
}
fs_initcall(eventpoll_init);
-
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff