* a better scalability.
*/
-#define DEBUG_EPOLL 0
-
-#if DEBUG_EPOLL > 0
-#define DPRINTK(x) printk x
-#define DNPRINTK(n, x) do { if ((n) <= DEBUG_EPOLL) printk x; } while (0)
-#else /* #if DEBUG_EPOLL > 0 */
-#define DPRINTK(x) (void) 0
-#define DNPRINTK(n, x) (void) 0
-#endif /* #if DEBUG_EPOLL > 0 */
-
-#define DEBUG_EPI 0
-
-#if DEBUG_EPI != 0
-#define EPI_SLAB_DEBUG (SLAB_DEBUG_FREE | SLAB_RED_ZONE /* | SLAB_POISON */)
-#else /* #if DEBUG_EPI != 0 */
-#define EPI_SLAB_DEBUG 0
-#endif /* #if DEBUG_EPI != 0 */
-
/* Epoll private bits inside the event mask */
#define EP_PRIVATE_BITS (EPOLLONESHOT | EPOLLET)
*/
struct nested_call_node {
struct list_head llink;
- struct task_struct *task;
void *cookie;
+ void *ctx;
};
/*
struct list_head llink;
/* The "base" pointer is set to the container "struct epitem" */
- void *base;
+ struct epitem *base;
/*
* Wait queue item that will be linked to the target file wait
.data = &max_user_watches,
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = &proc_dointvec_minmax,
+ .proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
},
- { .ctl_name = 0 }
+ { }
};
#endif /* CONFIG_SYSCTL */
* @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.
+ * @ctx: This instance context.
*
* Returns: Returns the code returned by the @nproc callback, or -1 if
* the maximum recursion limit has been exceeded.
*/
static int ep_call_nested(struct nested_calls *ncalls, int max_nests,
int (*nproc)(void *, void *, int), void *priv,
- void *cookie)
+ void *cookie, void *ctx)
{
int error, call_nests = 0;
unsigned long flags;
- struct task_struct *this_task = current;
struct list_head *lsthead = &ncalls->tasks_call_list;
struct nested_call_node *tncur;
struct nested_call_node tnode;
* very much limited.
*/
list_for_each_entry(tncur, lsthead, llink) {
- if (tncur->task == this_task &&
+ if (tncur->ctx == ctx &&
(tncur->cookie == cookie || ++call_nests > max_nests)) {
/*
* Ops ... loop detected or maximum nest level reached.
* We abort this wake by breaking the cycle itself.
*/
- spin_unlock_irqrestore(&ncalls->lock, flags);
-
- return -1;
+ error = -1;
+ goto out_unlock;
}
}
/* Add the current task and cookie to the list */
- tnode.task = this_task;
+ tnode.ctx = ctx;
tnode.cookie = cookie;
list_add(&tnode.llink, lsthead);
/* Remove the current task from the list */
spin_lock_irqsave(&ncalls->lock, flags);
list_del(&tnode.llink);
+out_unlock:
spin_unlock_irqrestore(&ncalls->lock, flags);
return error;
}
+#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
+
static int ep_poll_wakeup_proc(void *priv, void *cookie, int call_nests)
{
- wake_up_nested((wait_queue_head_t *) cookie, 1 + call_nests);
+ ep_wake_up_nested((wait_queue_head_t *) cookie, POLLIN,
+ 1 + call_nests);
return 0;
}
*/
static void ep_poll_safewake(wait_queue_head_t *wq)
{
+ int this_cpu = get_cpu();
+
ep_call_nested(&poll_safewake_ncalls, EP_MAX_NESTS,
- ep_poll_wakeup_proc, NULL, wq);
+ ep_poll_wakeup_proc, NULL, wq, (void *) (long) this_cpu);
+
+ put_cpu();
}
/*
- * This function unregister poll callbacks from the associated file descriptor.
- * Since this must be called without holding "ep->lock" the atomic exchange trick
- * will protect us from multiple unregister.
+ * This function unregisters poll callbacks from the associated file
+ * descriptor. Must be called with "mtx" held (or "epmutex" if called from
+ * ep_free).
*/
static void ep_unregister_pollwait(struct eventpoll *ep, struct epitem *epi)
{
- int nwait;
struct list_head *lsthead = &epi->pwqlist;
struct eppoll_entry *pwq;
- /* This is called without locks, so we need the atomic exchange */
- nwait = xchg(&epi->nwait, 0);
-
- if (nwait) {
- while (!list_empty(lsthead)) {
- pwq = list_first_entry(lsthead, struct eppoll_entry, llink);
+ while (!list_empty(lsthead)) {
+ pwq = list_first_entry(lsthead, struct eppoll_entry, llink);
- list_del_init(&pwq->llink);
- remove_wait_queue(pwq->whead, &pwq->wait);
- kmem_cache_free(pwq_cache, pwq);
- }
+ list_del(&pwq->llink);
+ remove_wait_queue(pwq->whead, &pwq->wait);
+ kmem_cache_free(pwq_cache, pwq);
}
}
int error, pwake = 0;
unsigned long flags;
struct epitem *epi, *nepi;
- struct list_head txlist;
-
- INIT_LIST_HEAD(&txlist);
+ LIST_HEAD(txlist);
/*
* We need to lock this because we could be hit by
- * eventpoll_release_file() and epoll_ctl(EPOLL_CTL_DEL).
+ * eventpoll_release_file() and epoll_ctl().
*/
mutex_lock(&ep->mtx);
* in a lockless way.
*/
spin_lock_irqsave(&ep->lock, flags);
- list_splice(&ep->rdllist, &txlist);
- INIT_LIST_HEAD(&ep->rdllist);
+ list_splice_init(&ep->rdllist, &txlist);
ep->ovflist = NULL;
spin_unlock_irqrestore(&ep->lock, flags);
if (!list_empty(&ep->rdllist)) {
/*
- * Wake up (if active) both the eventpoll wait list and the ->poll()
- * wait list (delayed after we release the lock).
+ * Wake up (if active) both the eventpoll wait list and
+ * the ->poll() wait list (delayed after we release the lock).
*/
if (waitqueue_active(&ep->wq))
wake_up_locked(&ep->wq);
atomic_dec(&ep->user->epoll_watches);
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: ep_remove(%p, %p)\n",
- current, ep, file));
-
return 0;
}
if (ep)
ep_free(ep);
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: close() ep=%p\n", current, ep));
return 0;
}
-static int ep_read_events_proc(struct eventpoll *ep, struct list_head *head, void *priv)
+static int ep_read_events_proc(struct eventpoll *ep, struct list_head *head,
+ void *priv)
{
struct epitem *epi, *tmp;
if (epi->ffd.file->f_op->poll(epi->ffd.file, NULL) &
epi->event.events)
return POLLIN | POLLRDNORM;
- else
+ else {
/*
* 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.
*/
list_del_init(&epi->rdllink);
+ }
}
return 0;
* could re-enter here.
*/
pollflags = ep_call_nested(&poll_readywalk_ncalls, EP_MAX_NESTS,
- ep_poll_readyevents_proc, ep, ep);
+ ep_poll_readyevents_proc, ep, ep, current);
- return pollflags != -1 ? pollflags: 0;
+ return pollflags != -1 ? pollflags : 0;
}
/* File callbacks that implement the eventpoll file behaviour */
*pep = ep;
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: ep_alloc() ep=%p\n",
- current, ep));
return 0;
free_uid:
}
}
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: ep_find(%p) -> %p\n",
- current, file, epir));
-
return epir;
}
struct epitem *epi = ep_item_from_wait(wait);
struct eventpoll *ep = epi->ep;
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: poll_callback(%p) epi=%p ep=%p\n",
- current, epi->ffd.file, epi, ep));
-
spin_lock_irqsave(&ep->lock, flags);
/*
goto out_unlock;
/*
+ * 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;
+
+ /*
* If we are trasfering events to userspace, we can hold no locks
* (because we're accessing user memory, and because of linux f_op->poll()
* semantics). All the events that happens during that period of time are
add_wait_queue(whead, &pwq->wait);
list_add_tail(&pwq->llink, &epi->pwqlist);
epi->nwait++;
- } else
+ } else {
/* We have to signal that an error occurred */
epi->nwait = -1;
+ }
}
static void ep_rbtree_insert(struct eventpoll *ep, struct epitem *epi)
if (pwake)
ep_poll_safewake(&ep->poll_wait);
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: ep_insert(%p, %p, %d)\n",
- current, ep, tfile, fd));
-
return 0;
error_unregister:
{
int pwake = 0;
unsigned int revents;
- unsigned long flags;
/*
- * Set the new event interest mask before calling f_op->poll(), otherwise
- * a potential race might occur. In fact if we do this operation inside
- * the lock, an event might happen between the f_op->poll() call and the
- * new event set registering.
+ * 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.
*/
epi->event.events = event->events;
+ epi->event.data = event->data; /* protected by mtx */
/*
* Get current event bits. We can safely use the file* here because
*/
revents = epi->ffd.file->f_op->poll(epi->ffd.file, NULL);
- spin_lock_irqsave(&ep->lock, flags);
-
- /* Copy the data member from inside the lock */
- epi->event.data = event->data;
-
/*
* If the item is "hot" and it is not registered inside the ready
* list, push it inside.
*/
if (revents & event->events) {
+ spin_lock_irq(&ep->lock);
if (!ep_is_linked(&epi->rdllink)) {
list_add_tail(&epi->rdllink, &ep->rdllist);
if (waitqueue_active(&ep->poll_wait))
pwake++;
}
+ spin_unlock_irq(&ep->lock);
}
- spin_unlock_irqrestore(&ep->lock, flags);
/* We have to call this outside the lock */
if (pwake)
return 0;
}
-static int ep_send_events_proc(struct eventpoll *ep, struct list_head *head, void *priv)
+static int ep_send_events_proc(struct eventpoll *ep, struct list_head *head,
+ void *priv)
{
struct ep_send_events_data *esed = priv;
int eventcnt;
- unsigned int revents;
+ unsigned int revents;
struct epitem *epi;
struct epoll_event __user *uevent;
- /*
+ /*
* 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.
- */
+ */
for (eventcnt = 0, uevent = esed->events;
!list_empty(head) && eventcnt < esed->maxevents;) {
epi = list_first_entry(head, struct epitem, rdllink);
list_del_init(&epi->rdllink);
- revents = epi->ffd.file->f_op->poll(epi->ffd.file, NULL) &
- epi->event.events;
+ revents = epi->ffd.file->f_op->poll(epi->ffd.file, NULL) &
+ epi->event.events;
- /*
+ /*
* 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.
- */
- if (revents) {
+ */
+ if (revents) {
if (__put_user(revents, &uevent->events) ||
- __put_user(epi->event.data, &uevent->data))
- return eventcnt ? eventcnt: -EFAULT;
- eventcnt++;
+ __put_user(epi->event.data, &uevent->data)) {
+ list_add(&epi->rdllink, head);
+ return eventcnt ? eventcnt : -EFAULT;
+ }
+ eventcnt++;
uevent++;
- if (epi->event.events & EPOLLONESHOT)
- epi->event.events &= EP_PRIVATE_BITS;
- else if (!(epi->event.events & EPOLLET))
- /*
- * If this file has been added with Level Trigger
- * mode, we need to insert back inside the ready
- * list, so that the next call to epoll_wait()
- * will check again the events availability.
- * At this point, noone can insert into ep->rdllist
- * besides us. The epoll_ctl() callers are locked
- * out by ep_scan_ready_list() holding "mtx" and
- * the poll callback will queue them in ep->ovflist.
- */
- list_add_tail(&epi->rdllink, &ep->rdllist);
- }
- }
+ if (epi->event.events & EPOLLONESHOT)
+ epi->event.events &= EP_PRIVATE_BITS;
+ else if (!(epi->event.events & EPOLLET)) {
+ /*
+ * If this file has been added with Level
+ * Trigger mode, we need to insert back inside
+ * the ready list, so that the next call to
+ * epoll_wait() will check again the events
+ * availability. At this point, noone can insert
+ * into ep->rdllist besides us. The epoll_ctl()
+ * callers are locked out by
+ * ep_scan_ready_list() holding "mtx" and the
+ * poll callback will queue them in ep->ovflist.
+ */
+ list_add_tail(&epi->rdllink, &ep->rdllist);
+ }
+ }
+ }
return eventcnt;
}
-static int ep_send_events(struct eventpoll *ep, struct epoll_event __user *events,
- int maxevents)
+static int ep_send_events(struct eventpoll *ep,
+ struct epoll_event __user *events, int maxevents)
{
struct ep_send_events_data esed;
/* Check the EPOLL_* constant for consistency. */
BUILD_BUG_ON(EPOLL_CLOEXEC != O_CLOEXEC);
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: sys_epoll_create(%d)\n",
- current, flags));
-
- error = -EINVAL;
if (flags & ~EPOLL_CLOEXEC)
- goto error_return;
-
+ return -EINVAL;
/*
* Create the internal data structure ("struct eventpoll").
*/
error = ep_alloc(&ep);
if (error < 0)
- goto error_return;
-
+ return error;
/*
* Creates all the items needed to setup an eventpoll file. That is,
* a file structure and a free file descriptor.
*/
error = anon_inode_getfd("[eventpoll]", &eventpoll_fops, ep,
- flags & O_CLOEXEC);
+ O_RDWR | (flags & O_CLOEXEC));
if (error < 0)
ep_free(ep);
-error_return:
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: sys_epoll_create(%d) = %d\n",
- current, flags, error));
-
return error;
}
SYSCALL_DEFINE1(epoll_create, int, size)
{
- if (size < 0)
+ if (size <= 0)
return -EINVAL;
return sys_epoll_create1(0);
struct epitem *epi;
struct epoll_event epds;
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: sys_epoll_ctl(%d, %d, %d, %p)\n",
- current, epfd, op, fd, event));
-
error = -EFAULT;
if (ep_op_has_event(op) &&
copy_from_user(&epds, event, sizeof(struct epoll_event)))
case EPOLL_CTL_ADD:
if (!epi) {
epds.events |= POLLERR | POLLHUP;
-
error = ep_insert(ep, &epds, tfile, fd);
} else
error = -EEXIST;
error_fput:
fput(file);
error_return:
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: sys_epoll_ctl(%d, %d, %d, %p) = %d\n",
- current, epfd, op, fd, event, error));
return error;
}
struct file *file;
struct eventpoll *ep;
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: sys_epoll_wait(%d, %p, %d, %d)\n",
- current, epfd, events, maxevents, timeout));
-
/* The maximum number of event must be greater than zero */
if (maxevents <= 0 || maxevents > EP_MAX_EVENTS)
return -EINVAL;
error_fput:
fput(file);
error_return:
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: sys_epoll_wait(%d, %p, %d, %d) = %d\n",
- current, epfd, events, maxevents, timeout, error));
return error;
}
/* 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);
+ 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, 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);
+ sizeof(struct eppoll_entry), 0, SLAB_PANIC, NULL);
return 0;
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff