From: Christoph Hellwig <hch@infradead.org>
To: Ming Lei <ming.lei@canonical.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Jens Axboe <axboe@kernel.dk>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Tejun Heo <tj@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Jarod Wilson <jarod@redhat.com>,
David Herrmann <dh.herrmann@gmail.com>,
Markus Pargmann <mpa@pengutronix.de>,
"nbd-general@lists.sourceforge.net"
<nbd-general@lists.sourceforge.net>,
Stefan Haberland <stefan.haberland@de.ibm.com>,
Sebastian Ott <sebott@linux.vnet.ibm.com>,
Fabian Frederick <fabf@skynet.be>,
linux-s390@vger.kernel.org
Subject: Re: [PATCH 1/6] block: export blkdev_reread_part()
Date: Mon, 6 Apr 2015 07:50:48 -0700 [thread overview]
Message-ID: <20150406145048.GC2703@infradead.org> (raw)
In-Reply-To: <CACVXFVP-rokGRrMus_QXju+MVzFPTaFC45oZBe2PEBfbid8nmQ@mail.gmail.com>
On Mon, Apr 06, 2015 at 12:40:12AM +0800, Ming Lei wrote:
> > int blkdev_reread_part(struct block_device *bdev)
> > {
> > if (!mutex_trylock(&bdev->bd_mutex))
> > return -EBUSY;
> > blkdev_reread_part_nolock(bdev);
> > mutex_unlock(&bdev->bd_mutex);
> > }
>
> Yes, it is more clean, but with extra acquiring lock cost for the
> failure cases, especially when we replace trylock with mutex_lock().
It's just a few fairly trivial checks, so 'm not really worried about
it, especially given that blkdev_reread_part isn't called from a fast
path.
next prev parent reply other threads:[~2015-04-06 14:50 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-05 7:24 [PATCH 0/6] block: reread partitions changes and fix for loop Ming Lei
2015-04-05 7:24 ` [PATCH 1/6] block: export blkdev_reread_part() Ming Lei
2015-04-05 16:12 ` Christoph Hellwig
2015-04-05 16:40 ` Ming Lei
2015-04-06 13:42 ` Jarod Wilson
2015-04-06 13:48 ` Jarod Wilson
2015-04-07 2:43 ` Ming Lei
2015-04-06 14:50 ` Christoph Hellwig [this message]
2015-04-07 2:11 ` Ming Lei
2015-04-05 7:24 ` [PATCH 2/6] block: loop: don't hold lo_ctl_mutex in lo_open Ming Lei
2015-04-05 16:28 ` Ming Lei
2015-04-06 14:49 ` Christoph Hellwig
2015-04-05 7:24 ` [PATCH 3/6] block: loop: fix another reread part failure Ming Lei
2015-04-05 7:24 ` [PATCH 4/6] block: nbd: convert to blkdev_reread_part() Ming Lei
2015-04-05 7:24 ` [PATCH 5/6] block: dasd_genhd: convert to blkdev_reread_part Ming Lei
2015-04-06 13:46 ` Jarod Wilson
2015-04-06 13:51 ` Jarod Wilson
2015-04-07 1:59 ` Ming Lei
2015-04-07 0:47 ` Ming Lei
2015-04-05 7:24 ` [RFC PATCH 6/6] block: replace trylock with mutex_lock in __blkdev_reread_part() Ming Lei
2015-04-08 6:23 ` [PATCH 0/7] block: reread partitions improvements Jarod Wilson
2015-04-08 6:23 ` [PATCH 1/7] block: export blkdev_reread_part() and __blkdev_reread_part() Jarod Wilson
2015-04-08 14:50 ` Ming Lei
2015-04-08 15:03 ` Peter Zijlstra
2015-04-08 15:27 ` Jarod Wilson
2015-04-08 15:28 ` Ming Lei
2015-04-08 6:23 ` [PATCH 2/7] block: loop: don't hold lo_ctl_mutex in lo_open Jarod Wilson
2015-04-08 6:50 ` Ming Lei
2015-04-08 13:40 ` Jarod Wilson
2015-04-08 14:00 ` Jarod Wilson
2015-04-08 14:20 ` Ming Lei
2015-04-08 15:28 ` Jarod Wilson
2015-04-08 6:23 ` [PATCH 3/7] block: loop: fix another reread part failure Jarod Wilson
2015-04-08 6:23 ` [PATCH 4/7] block: nbd: convert to blkdev_reread_part() Jarod Wilson
2015-04-08 6:23 ` [PATCH 5/7] block: dasd_genhd: convert to blkdev_reread_part Jarod Wilson
2015-04-08 6:23 ` [PATCH 6/7] block: replace trylock with mutex_lock in blkdev_reread_part() Jarod Wilson
2015-04-08 6:23 ` [PATCH 7/7] s390/block/dasd: remove obsolete while -EBUSY loop Jarod Wilson
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