From: Paul Clements <Paul.Clements@SteelEye.com>
To: Jens Axboe <axboe@suse.de>, Lou Langholtz <ldl@aros.net>
Cc: Andrew Morton <akpm@osdl.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] 2.6.0 NBD driver: remove send/recieve race for request
Date: Fri, 08 Aug 2003 11:00:58 -0400 [thread overview]
Message-ID: <3F33BB2A.94599C5C@SteelEye.com> (raw)
In-Reply-To: 20030808065908.GB18823@suse.de
Jens Axboe wrote:
>
> On Fri, Aug 08 2003, Lou Langholtz wrote:
> > >@@ -499,12 +508,14 @@ static void do_nbd_request(request_queue
> > > lo->disk->disk_name);
> > > spin_lock(&lo->queue_lock);
> > > list_del_init(&req->queuelist);
> > >+ req->ref_count--;
> > > spin_unlock(&lo->queue_lock);
> > > nbd_end_request(req);
> > > spin_lock_irq(q->queue_lock);
> > > continue;
> > > }
> > >
> > >+ req->ref_count--;
> > > spin_lock_irq(q->queue_lock);
> > >
> > Since ref_count isn't atomic, shouldn't ref_count only be changed while
> > the queue_lock is held???
>
> Indeed, needs to be done after regrabbing the lock.
But req is pulled off of nbd's main request queue at this point, so I
don't think anyone else could be touching it, could they?
--
Paul
next prev parent reply other threads:[~2003-08-08 15:02 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-05 16:51 [PATCH] 2.6.0 NBD driver: remove send/recieve race for request Lou Langholtz
2003-08-05 19:37 ` Paul Clements
2003-08-05 22:48 ` Lou Langholtz
2003-08-06 0:51 ` Paul Clements
2003-08-06 7:34 ` Lou Langholtz
2003-08-08 5:02 ` Paul Clements
2003-08-08 5:27 ` Andrew Morton
2003-08-08 17:05 ` Paul Clements
2003-08-08 6:30 ` Lou Langholtz
2003-08-08 6:43 ` Andrew Morton
2003-08-08 6:59 ` Jens Axboe
2003-08-08 15:00 ` Paul Clements [this message]
2003-08-25 9:58 ` Jens Axboe
2003-08-08 16:47 ` Paul Clements
2003-08-08 20:07 ` [PATCH 2.6.0-test2-mm] nbd: fix send/receive/shutdown/disconnect races Paul Clements
2003-08-09 22:10 ` [PATCH 2.4.22-pre] nbd: fix race conditions Paul Clements
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=3F33BB2A.94599C5C@SteelEye.com \
--to=paul.clements@steeleye.com \
--cc=akpm@osdl.org \
--cc=axboe@suse.de \
--cc=ldl@aros.net \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).