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| author | Davidlohr Bueso <dave@stgolabs.net> | 2018-08-21 21:56:41 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-22 10:52:47 -0700 |
| commit | 304b18b8d6af796c8ece221d34c92aeb1559789b (patch) | |
| tree | 76bb535c6a21095ad314d3f522bb7a161beb0801 | |
| parent | 002b343669c474151954266e7fcf727bf7faa851 (diff) | |
| download | linux-stable-304b18b8d6af796c8ece221d34c92aeb1559789b.tar.gz linux-stable-304b18b8d6af796c8ece221d34c92aeb1559789b.tar.bz2 linux-stable-304b18b8d6af796c8ece221d34c92aeb1559789b.zip | |
fs/epoll: loosen irq safety in epoll_insert() and epoll_remove()
Both functions are similar to the context of ep_modify(), called via
epoll_ctl(2). Just like ep_modify(), saving and restoring interrupts is
an overkill in these calls as it will never be called with irqs disabled.
While ep_remove() can be called directly from EPOLL_CTL_DEL, it can also
be called when releasing the file, but this also complies with the above.
Link: http://lkml.kernel.org/r/20180720172956.2883-3-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/eventpoll.c | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 2247769eb941..1b1abc461fc0 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -762,7 +762,6 @@ static void epi_rcu_free(struct rcu_head *head) */ static int ep_remove(struct eventpoll *ep, struct epitem *epi) { - unsigned long flags; struct file *file = epi->ffd.file; /* @@ -777,10 +776,10 @@ static int ep_remove(struct eventpoll *ep, struct epitem *epi) rb_erase_cached(&epi->rbn, &ep->rbr); - spin_lock_irqsave(&ep->wq.lock, flags); + spin_lock_irq(&ep->wq.lock); if (ep_is_linked(&epi->rdllink)) list_del_init(&epi->rdllink); - spin_unlock_irqrestore(&ep->wq.lock, flags); + spin_unlock_irq(&ep->wq.lock); wakeup_source_unregister(ep_wakeup_source(epi)); /* @@ -1409,7 +1408,6 @@ static int ep_insert(struct eventpoll *ep, const struct epoll_event *event, { int error, pwake = 0; __poll_t revents; - unsigned long flags; long user_watches; struct epitem *epi; struct ep_pqueue epq; @@ -1476,7 +1474,7 @@ static int ep_insert(struct eventpoll *ep, const struct epoll_event *event, goto error_remove_epi; /* We have to drop the new item inside our item list to keep track of it */ - spin_lock_irqsave(&ep->wq.lock, flags); + spin_lock_irq(&ep->wq.lock); /* record NAPI ID of new item if present */ ep_set_busy_poll_napi_id(epi); @@ -1493,7 +1491,7 @@ static int ep_insert(struct eventpoll *ep, const struct epoll_event *event, pwake++; } - spin_unlock_irqrestore(&ep->wq.lock, flags); + spin_unlock_irq(&ep->wq.lock); atomic_long_inc(&ep->user->epoll_watches); @@ -1519,10 +1517,10 @@ error_unregister: * list, since that is used/cleaned only inside a section bound by "mtx". * And ep_insert() is called with "mtx" held. */ - spin_lock_irqsave(&ep->wq.lock, flags); + spin_lock_irq(&ep->wq.lock); if (ep_is_linked(&epi->rdllink)) list_del_init(&epi->rdllink); - spin_unlock_irqrestore(&ep->wq.lock, flags); + spin_unlock_irq(&ep->wq.lock); wakeup_source_unregister(ep_wakeup_source(epi)); |