From: Roman Penyaev <rpenyaev@suse.de>
To: unlisted-recipients:; (no To-header on input)
Cc: Roman Penyaev <rpenyaev@suse.de>,
Davidlohr Bueso <dbueso@suse.de>, Jason Baron <jbaron@akamai.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/3] epoll: loosen irq safety in ep_poll_callback()
Date: Wed, 12 Dec 2018 12:03:56 +0100 [thread overview]
Message-ID: <20181212110357.25656-3-rpenyaev@suse.de> (raw)
In-Reply-To: <20181212110357.25656-1-rpenyaev@suse.de>
Callers of the ep_poll_callback() (all set of wake_up_*poll()) disable
interrupts, so no need to save/restore irq flags.
Signed-off-by: Roman Penyaev <rpenyaev@suse.de>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
fs/eventpoll.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 3627c2e07149..ea0025e77519 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1124,13 +1124,15 @@ struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd,
static int ep_poll_callback(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
{
int pwake = 0;
- unsigned long flags;
struct epitem *epi = ep_item_from_wait(wait);
struct eventpoll *ep = epi->ep;
__poll_t pollflags = key_to_poll(key);
int ewake = 0;
- spin_lock_irqsave(&ep->wq.lock, flags);
+ /* Interrupts are disabled by the wake_up_*poll() callers */
+ lockdep_assert_irqs_disabled();
+
+ spin_lock(&ep->wq.lock);
ep_set_busy_poll_napi_id(epi);
@@ -1207,7 +1209,7 @@ static int ep_poll_callback(wait_queue_entry_t *wait, unsigned mode, int sync, v
pwake++;
out_unlock:
- spin_unlock_irqrestore(&ep->wq.lock, flags);
+ spin_unlock(&ep->wq.lock);
/* We have to call this outside the lock */
if (pwake)
--
2.19.1
next prev parent reply other threads:[~2018-12-12 11:04 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-12 11:03 [PATCH 0/3] use rwlock in order to reduce ep_poll_callback() contention Roman Penyaev
2018-12-12 11:03 ` [PATCH 1/3] epoll: make sure all elements in ready list are in FIFO order Roman Penyaev
2018-12-13 19:30 ` Davidlohr Bueso
2018-12-12 11:03 ` Roman Penyaev [this message]
2018-12-12 11:03 ` [PATCH 3/3] epoll: use rwlock in order to reduce ep_poll_callback() contention Roman Penyaev
[not found] ` <20181212171348.GA12786@andrea>
2018-12-13 10:13 ` Roman Penyaev
2018-12-13 11:19 ` Andrea Parri
2018-12-13 12:19 ` Roman Penyaev
2018-12-13 18:13 ` [PATCH 0/3] " Davidlohr Bueso
2018-12-17 11:49 ` Roman Penyaev
2018-12-17 18:01 ` Davidlohr Bueso
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