From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41322) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WTfvG-0004zP-Kg for qemu-devel@nongnu.org; Fri, 28 Mar 2014 19:10:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WTfvA-0000yx-FP for qemu-devel@nongnu.org; Fri, 28 Mar 2014 19:10:50 -0400 Message-ID: <53360160.5060802@redhat.com> Date: Sat, 29 Mar 2014 00:10:24 +0100 From: Max Reitz MIME-Version: 1.0 References: <1395835569-21193-1-git-send-email-stefanha@redhat.com> <1395835569-21193-35-git-send-email-stefanha@redhat.com> In-Reply-To: <1395835569-21193-35-git-send-email-stefanha@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH for-2.0 34/47] dmg: drop broken bdrv_pread() loop List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi , qemu-devel@nongnu.org Cc: Kevin Wolf , pmatouse@redhat.com, qemu-stable@nongnu.org On 26.03.2014 13:05, Stefan Hajnoczi wrote: > It is not necessary to check errno for EINTR and the block layer does > not produce short reads. Therefore we can drop the loop that attempts > to read a compressed chunk. > > The loop is buggy because it incorrectly adds the transferred bytes > twice: > > do { > ret = bdrv_pread(...); > i += ret; > } while (ret >= 0 && ret + i < s->lengths[chunk]); > > Luckily we can drop the loop completely and perform a single > bdrv_pread(). > > Signed-off-by: Stefan Hajnoczi > Signed-off-by: Kevin Wolf > --- > block/dmg.c | 15 ++------------- > 1 file changed, 2 insertions(+), 13 deletions(-) Reviewed-by: Max Reitz