linux-kernel - Re: [PATCH 5/6] fs/epoll: reduce the scope of wq lock in epoll

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Message-ID: <20181109155258.jxcr4t2pnz6zqct3@linux-r8p5>
Date:   Fri, 9 Nov 2018 07:52:58 -0800
From:   Davidlohr Bueso <dave@...olabs.net>
To:     akpm@...ux-foundation.org
Cc:     jbaron@...mai.com, viro@...iv.linux.org.uk,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        Davidlohr Bueso <dbueso@...e.de>
Subject: Re: [PATCH 5/6] fs/epoll: reduce the scope of wq lock in epoll_wait()

Sorry, I just realized I forgot these fixlets when sending the v1.

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index ec14e5bcdaa9..c37729658c03 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -381,7 +381,7 @@ static void ep_nested_calls_init(struct nested_calls *ncalls)
  */
 static inline int ep_events_available(struct eventpoll *ep)
 {
-	return !list_empty(&ep->rdllist) ||
+	return !list_empty_careful(&ep->rdllist) ||
 		READ_ONCE(ep->ovflist) != EP_UNACTIVE_PTR;
 }
 
@@ -1820,8 +1820,9 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
 			res = -EINTR;
 			break;
 		}
-		
-		if (ep_events_available(ep))
+
+		eavail = ep_events_available(ep);
+		if (eavail)
 			break;
 		if (signal_pending(current)) {
 			res = -EINTR;