From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56852) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wx1Ka-00036M-0t for qemu-devel@nongnu.org; Tue, 17 Jun 2014 17:54:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Wx1KU-0001aq-Bo for qemu-devel@nongnu.org; Tue, 17 Jun 2014 17:54:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55539) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wx1KU-0001ak-2m for qemu-devel@nongnu.org; Tue, 17 Jun 2014 17:54:10 -0400 From: Jeff Cody Date: Tue, 17 Jun 2014 17:53:51 -0400 Message-Id: <9881c231a71da7224d394466f837699f54338c63.1403041699.git.jcody@redhat.com> In-Reply-To: References: In-Reply-To: References: Subject: [Qemu-devel] [PATCH v6 for 2.1 03/10] block: simplify bdrv_find_base() and bdrv_find_overlay() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, benoit.canet@irqsave.net, pkrempa@redhat.com, famz@redhat.com, stefanha@redhat.com This simplifies the function bdrv_find_overlay(). With this change, bdrv_find_base() is just a subset of usage of bdrv_find_overlay(), so this also takes advantage of that. Reviewed-by: Eric Blake Reviewed-by: Benoit Canet Signed-off-by: Jeff Cody --- block.c | 45 ++++++++++----------------------------------- 1 file changed, 10 insertions(+), 35 deletions(-) diff --git a/block.c b/block.c index 280a167..f9ffca4 100644 --- a/block.c +++ b/block.c @@ -2566,32 +2566,23 @@ int bdrv_change_backing_file(BlockDriverState *bs, * * Returns NULL if bs is not found in active's image chain, * or if active == bs. + * + * Returns the bottommost base image if bs == NULL. */ BlockDriverState *bdrv_find_overlay(BlockDriverState *active, BlockDriverState *bs) { - BlockDriverState *overlay = NULL; - BlockDriverState *intermediate; - - assert(active != NULL); - assert(bs != NULL); - - /* if bs is the same as active, then by definition it has no overlay - */ - if (active == bs) { - return NULL; + while (active && bs != active->backing_hd) { + active = active->backing_hd; } - intermediate = active; - while (intermediate->backing_hd) { - if (intermediate->backing_hd == bs) { - overlay = intermediate; - break; - } - intermediate = intermediate->backing_hd; - } + return active; +} - return overlay; +/* Given a BDS, searches for the base layer. */ +BlockDriverState *bdrv_find_base(BlockDriverState *bs) +{ + return bdrv_find_overlay(bs, NULL); } typedef struct BlkIntermediateStates { @@ -4373,22 +4364,6 @@ int bdrv_get_backing_file_depth(BlockDriverState *bs) return 1 + bdrv_get_backing_file_depth(bs->backing_hd); } -BlockDriverState *bdrv_find_base(BlockDriverState *bs) -{ - BlockDriverState *curr_bs = NULL; - - if (!bs) { - return NULL; - } - - curr_bs = bs; - - while (curr_bs->backing_hd) { - curr_bs = curr_bs->backing_hd; - } - return curr_bs; -} - /**************************************************************/ /* async I/Os */ -- 1.9.3