From: Jeff Layton <jlayton@redhat.com>
To: David Howells <dhowells@redhat.com>
Cc: torvalds@linux-foundation.org, linux-nfs@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-cachefs@redhat.com,
Milosz Tanski <milosz@adfin.com>,
Yacine Belkadi <yacine.belkadi.1@gmail.com>
Subject: Re: [PATCH] Fix __wait_on_atomic_t() to call the action func if the counter != 0
Date: Tue, 23 Jul 2013 12:26:29 -0400 [thread overview]
Message-ID: <20130723122629.6b5ae46e@tlielax.poochiereds.net> (raw)
In-Reply-To: <24785.1374596102@warthog.procyon.org.uk>
On Tue, 23 Jul 2013 17:15:02 +0100
David Howells <dhowells@redhat.com> wrote:
> Jeff Layton <jlayton@redhat.com> wrote:
>
> > > @@ -333,7 +333,8 @@ int __wait_on_atomic_t(wait_queue_head_t *wq, struct wait_bit_queue *q,
> > > prepare_to_wait(wq, &q->wait, mode);
> > > val = q->key.flags;
> > > if (atomic_read(val) == 0)
> > > - ret = (*action)(val);
> > > + break;
> > > + ret = (*action)(val);
> > > } while (!ret && atomic_read(val) != 0);
> >
> > nit: can you now eliminate the check for "val" in the while condition?
> > It doesn't look like it harms anything, but eliminating it would
> > probably simplify the code slightly...
>
> Its presence means that we don't have to call prepare_to_wait() again if val
> became 0.
>
> David
Ok, and prepare_to_wait involves taking spinlocks, etc...
Got it!
Reviewed-by: Jeff Layton <jlayton@redhat.com>
prev parent reply other threads:[~2013-07-23 16:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-23 15:49 David Howells
2013-07-23 16:02 ` Jeff Layton
2013-07-23 16:15 ` David Howells
2013-07-23 16:26 ` Jeff Layton [this message]
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