diff options
| -rw-r--r-- | fs/eventpoll.c | 110 |
1 files changed, 57 insertions, 53 deletions
diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 8a23a91..e24d137 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) |