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| author | Arnd Bergmann <arnd@arndb.de> | 2012-02-28 12:33:41 +0000 |
|---|---|---|
| committer | Arnd Bergmann <arnd@arndb.de> | 2012-02-28 12:33:46 +0000 |
| commit | abf45ce84c4e36bd64aef20d7df9a79bd5e4b799 (patch) | |
| tree | f118e135bdd60b680703d1b38c7fdc7b9d7c503d /fs/eventpoll.c | |
| parent | 082f53c2f573c75a8f1610c587a43b6817e20f90 (diff) | |
| parent | b1f91a9ce335eb4e0fef17c10f39a438ac3fce9b (diff) | |
Merge branch 'imx/defconfig' of git://git.linaro.org/people/shawnguo/linux-2.6 into next/soc
* 'imx/defconfig' of git://git.linaro.org/people/shawnguo/linux-2.6: (2 commits)
ARM: defconfig: imx_v6_v7: build in REGULATOR_FIXED_VOLTAGE
ARM: imx: update imx_v6_v7_defconfig
(upadte to v3.3-rc5)
Diffstat (limited to 'fs/eventpoll.c')
| -rw-r--r-- | fs/eventpoll.c | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/fs/eventpoll.c b/fs/eventpoll.c index aabdfc38cf2..ea54cdef04d 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -320,6 +320,11 @@ static inline int ep_is_linked(struct list_head *p) return !list_empty(p); } +static inline struct eppoll_entry *ep_pwq_from_wait(wait_queue_t *p) +{ + return container_of(p, struct eppoll_entry, wait); +} + /* Get the "struct epitem" from a wait queue pointer */ static inline struct epitem *ep_item_from_wait(wait_queue_t *p) { @@ -467,6 +472,18 @@ static void ep_poll_safewake(wait_queue_head_t *wq) put_cpu(); } +static void ep_remove_wait_queue(struct eppoll_entry *pwq) +{ + wait_queue_head_t *whead; + + rcu_read_lock(); + /* If it is cleared by POLLFREE, it should be rcu-safe */ + whead = rcu_dereference(pwq->whead); + if (whead) + remove_wait_queue(whead, &pwq->wait); + rcu_read_unlock(); +} + /* * This function unregisters poll callbacks from the associated file * descriptor. Must be called with "mtx" held (or "epmutex" if called from @@ -481,7 +498,7 @@ static void ep_unregister_pollwait(struct eventpoll *ep, struct epitem *epi) pwq = list_first_entry(lsthead, struct eppoll_entry, llink); list_del(&pwq->llink); - remove_wait_queue(pwq->whead, &pwq->wait); + ep_remove_wait_queue(pwq); kmem_cache_free(pwq_cache, pwq); } } @@ -842,6 +859,17 @@ static int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *k struct epitem *epi = ep_item_from_wait(wait); struct eventpoll *ep = epi->ep; + if ((unsigned long)key & POLLFREE) { + ep_pwq_from_wait(wait)->whead = NULL; + /* + * whead = NULL above can race with ep_remove_wait_queue() + * which can do another remove_wait_queue() after us, so we + * can't use __remove_wait_queue(). whead->lock is held by + * the caller. + */ + list_del_init(&wait->task_list); + } + spin_lock_irqsave(&ep->lock, flags); /* |