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>
This commit is contained in:
Davide Libenzi
Linus Torvalds
Родитель
5071f97ec6
Коммит
296e236e96
110
fs/eventpoll.c
110
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)
|
||||
|
|
|
|||
Загрузка…
Ссылка в новой задаче