From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34119) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XKkR7-0007N1-98 for qemu-devel@nongnu.org; Fri, 22 Aug 2014 04:43:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XKkR2-00078a-5j for qemu-devel@nongnu.org; Fri, 22 Aug 2014 04:43:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59294) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XKkR1-00078O-T0 for qemu-devel@nongnu.org; Fri, 22 Aug 2014 04:43:00 -0400 Date: Fri, 22 Aug 2014 10:42:46 +0200 From: Kevin Wolf Message-ID: <20140822084246.GA32377@noname.redhat.com> References: <00c425bd67fc66567dc683205f8f60f7.squirrel@ssl.dlhnet.de> <53F6F3DD.2090804@kamp.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53F6F3DD.2090804@kamp.de> Subject: Re: [Qemu-devel] [Fwd: [PATCH v4 07/21] iscsi: Handle failure for potentially large allocations] List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Lieven Cc: benoit.canet@irqsave.net, Paolo Bonzini , maxa@catit.be, qemu-devel@nongnu.org, stefanha@redhat.com Am 22.08.2014 um 09:40 hat Peter Lieven geschrieben: > Am 22.08.2014 um 09:35 schrieb Peter Lieven: > > Some code in the block layer makes potentially huge allocations. Failure > > is not completely unexpected there, so avoid aborting qemu and handle > > out-of-memory situations gracefully. > > > > This patch addresses the allocations in the iscsi block driver. > > > > Signed-off-by: Kevin Wolf > > Acked-by: Paolo Bonzini > > Reviewed-by: Benoit Canet > > Reviewed-by: Eric Blake > > --- > > block/iscsi.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/block/iscsi.c b/block/iscsi.c > > index 84aa22a..06afa78 100644 > > --- a/block/iscsi.c > > +++ b/block/iscsi.c > > @@ -893,7 +893,10 @@ coroutine_fn iscsi_co_write_zeroes(BlockDriverState > > *bs, int64_t sector_num, > > nb_blocks = sector_qemu2lun(nb_sectors, iscsilun); > > > > if (iscsilun->zeroblock == NULL) { > > - iscsilun->zeroblock = g_malloc0(iscsilun->block_size); > > + iscsilun->zeroblock = g_try_malloc0(iscsilun->block_size); > > + if (iscsilun->zeroblock == NULL) { > > + return -ENOMEM; > > + } > > } > > > > iscsi_co_init_iscsitask(iscsilun, &iTask); > > Unfortunately, I missed that one. The zeroblock is typicalls 512 Byte or 4K depending > on the blocksize. I don't remember the details, but I think when I went through all drivers, I couldn't convince myself that a reasonable block size is enforced somewhere. So I just went ahead and converted the call to be on the safe side. It can never hurt anyway. > What is significantly larger is the allocationmap. It is typically created > on iscsi_open, but is also recreated on iscsi_truncate. I don't have the context why this > patch was introduced, but I would vote for introducing a bitmap_try_new and issue > a warning if the allocation fails. The allocationmap is optional we can work without it. > If the pointer is NULL its not used. Right, that one I missed because it doesn't directly use g_malloc(). Your proposal sounds good to me. Are you going to prepare a patch? Kevin