From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55774) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VLvgh-00072F-2a for qemu-devel@nongnu.org; Tue, 17 Sep 2013 09:51:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VLvga-0001ua-1Z for qemu-devel@nongnu.org; Tue, 17 Sep 2013 09:51:31 -0400 Received: from mx.ipv6.kamp.de ([2a02:248:0:51::16]:42647 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VLvgZ-0001uE-N1 for qemu-devel@nongnu.org; Tue, 17 Sep 2013 09:51:23 -0400 From: Peter Lieven Date: Tue, 17 Sep 2013 15:48:44 +0200 Message-Id: <1379425736-11326-9-git-send-email-pl@kamp.de> In-Reply-To: <1379425736-11326-1-git-send-email-pl@kamp.de> References: <1379425736-11326-1-git-send-email-pl@kamp.de> Subject: [Qemu-devel] [PATCHv2 08/20] block: honour alignment and limit in bdrv_co_discard List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, ronniesahlberg@gmail.com, Peter Lieven , stefanha@redhat.com, anthony@codemonkey.ws, pbonzini@redhat.com Signed-off-by: Peter Lieven --- block.c | 34 +++++++++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-) diff --git a/block.c b/block.c index 74ec342..ecc5be4 100644 --- a/block.c +++ b/block.c @@ -4181,7 +4181,39 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, } if (bs->drv->bdrv_co_discard) { - return bs->drv->bdrv_co_discard(bs, sector_num, nb_sectors); + /* if no limit is specified in the BlockDriverState use a default + * of 32768 512-byte sectors (16 MiB) per request. + */ + int max_discard = bs->max_discard ? bs->max_discard : 32768; + + while (nb_sectors > 0) { + int ret; + int num = nb_sectors; + + /* align request */ + if (bs->discard_alignment && + num >= bs->discard_alignment && + sector_num % bs->discard_alignment) { + if (num > bs->discard_alignment) { + num = bs->discard_alignment; + } + num -= sector_num % bs->discard_alignment; + } + + /* limit request size */ + if (num > max_discard) { + num = max_discard; + } + + ret = bs->drv->bdrv_co_discard(bs, sector_num, num); + if (ret) { + return ret; + } + + sector_num += num; + nb_sectors -= num; + } + return 0; } else if (bs->drv->bdrv_aio_discard) { BlockDriverAIOCB *acb; CoroutineIOCompletion co = { -- 1.7.9.5