#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;
* 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 devices, per user */
+static int max_user_instances __read_mostly;
+/* 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_instances",
+ .data = &max_user_instances,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_minmax,
+ .extra1 = &zero,
+ },
+ {
+ .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 */
static inline void ep_set_ffd(struct epoll_filefd *ffd,
(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);
list_del_init(&epi->fllink);
spin_unlock(&file->f_ep_lock);
- if (ep_rb_linked(&epi->rbn))
- ep_rb_erase(&epi->rbn, &ep->rbr);
+ rb_erase(&epi->rbn, &ep->rbr);
spin_lock_irqsave(&ep->lock, flags);
if (ep_is_linked(&epi->rdllink))
/* At this point it is safe to free the eventpoll item */
kmem_cache_free(epi_cache, epi);
+ atomic_dec(&ep->user->epoll_watches);
+
DNPRINTK(3, (KERN_INFO "[%p] eventpoll: ep_remove(%p, %p)\n",
current, ep, file));
* 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);
+ atomic_dec(&ep->user->epoll_devs);
+ free_uid(ep->user);
kfree(ep);
}
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 = -EMFILE;
+ if (unlikely(atomic_read(&user->epoll_devs) >=
+ max_user_instances))
+ goto free_uid;
+ error = -ENOMEM;
+ ep = kzalloc(sizeof(*ep), GFP_KERNEL);
+ if (unlikely(!ep))
+ goto free_uid;
spin_lock_init(&ep->lock);
mutex_init(&ep->mtx);
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;
}
/*
* 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++;
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);
* install process. Namely an allocation for a wait queue failed due
* high memory pressure.
*/
+ error = -ENOMEM;
if (epi->nwait < 0)
goto error_unregister;
/* 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++;
}
spin_unlock_irqrestore(&ep->lock, flags);
+ atomic_inc(&ep->user->epoll_watches);
+
/* We have to call this outside the lock */
if (pwake)
ep_poll_safewake(&psw, &ep->poll_wait);
spin_unlock_irqrestore(&ep->lock, flags);
kmem_cache_free(epi_cache, epi);
-error_return:
+
return error;
}
/* 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++;
}
/*
* 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);
}
/*
* 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++;
}
}
/*
- * It opens an eventpoll file descriptor. The "size" parameter is there
- * for historical reasons, when epoll was using an hash instead of an
- * RB tree. With the current implementation, the "size" parameter is ignored
- * (besides sanity checks).
+ * Open an eventpoll file descriptor.
*/
-asmlinkage long sys_epoll_create(int size)
+asmlinkage long sys_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);
+ atomic_inc(&ep->user->epoll_devs);
+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);
-error_return:
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: sys_epoll_create(%d) = %d\n",
- current, size, error));
- return error;
+asmlinkage long sys_epoll_create(int size)
+{
+ if (size < 0)
+ return -EINVAL;
+
+ return sys_epoll_create1(0);
}
/*
return error;
}
-#ifdef TIF_RESTORE_SIGMASK
+#ifdef HAVE_SET_RESTORE_SIGMASK
/*
* Implement the event wait interface for the eventpoll file. It is the kernel
if (error == -EINTR) {
memcpy(¤t->saved_sigmask, &sigsaved,
sizeof(sigsaved));
- set_thread_flag(TIF_RESTORE_SIGMASK);
+ 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);
+ max_user_instances = 128;
+ max_user_watches = (((si.totalram - si.totalhigh) / 32) << 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