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authorDavide Libenzi <davidel@xmailserver.org>2009-03-31 15:24:11 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-01 08:59:19 -0700
commit296e236e96dddef351a1809c0d414bcddfcf3800 (patch)
tree279d6eb3f0114a49897cd4bbc0eaf43fffd46c6e /fs/eventpoll.c
parent5071f97ec6d74f006072de0ce89b67c8792fe5a1 (diff)
downloadvexpress-lsk-296e236e96dddef351a1809c0d414bcddfcf3800.tar.gz
epoll: fix epoll's own poll (update)
Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Cc: Pavel Pisa <pisa@cmp.felk.cvut.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/eventpoll.c')
-rw-r--r--fs/eventpoll.c110
1 files changed, 57 insertions, 53 deletions
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 8a23a91e137..e24d137c93b 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -454,9 +454,7 @@ static int ep_scan_ready_list(struct eventpoll *ep,
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
@@ -473,8 +471,7 @@ static int ep_scan_ready_list(struct eventpoll *ep,
* 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);
@@ -514,8 +511,8 @@ static int ep_scan_ready_list(struct eventpoll *ep,
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);
@@ -632,7 +629,8 @@ static int ep_eventpoll_release(struct inode *inode, struct file *file)
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;
@@ -640,13 +638,14 @@ static int ep_read_events_proc(struct eventpoll *ep, struct list_head *head, voi
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;
@@ -674,7 +673,7 @@ static unsigned int ep_eventpoll_poll(struct file *file, poll_table *wait)
pollflags = ep_call_nested(&poll_readywalk_ncalls, EP_MAX_NESTS,
ep_poll_readyevents_proc, ep, ep);
- return pollflags != -1 ? pollflags: 0;
+ return pollflags != -1 ? pollflags : 0;
}
/* File callbacks that implement the eventpoll file behaviour */
@@ -872,9 +871,10 @@ static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead,
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)
@@ -1055,62 +1055,65 @@ static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_even
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++;
+ 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;
@@ -1194,40 +1197,41 @@ retry:
*/
SYSCALL_DEFINE1(epoll_create1, int, flags)
{
- int error;
- struct eventpoll *ep = NULL;
+ int error, fd = -1;
+ struct eventpoll *ep;
/* 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, flags));
- error = -EINVAL;
- if (flags & ~EPOLL_CLOEXEC)
- goto error_return;
-
/*
- * Create the internal data structure ("struct eventpoll").
+ * Create the internal data structure ( "struct eventpoll" ).
*/
error = ep_alloc(&ep);
- if (error < 0)
+ if (error < 0) {
+ fd = error;
goto error_return;
+ }
/*
* 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);
- if (error < 0)
+ 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, flags, error));
+ current, flags, fd));
- return error;
+ return fd;
}
SYSCALL_DEFINE1(epoll_create, int, size)