From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:32980) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bGDG0-0004kt-Re for qemu-devel@nongnu.org; Thu, 23 Jun 2016 18:38:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bGDFz-00061J-Pd for qemu-devel@nongnu.org; Thu, 23 Jun 2016 18:37:56 -0400 From: Eric Blake Date: Thu, 23 Jun 2016 16:37:23 -0600 Message-Id: <1466721446-27737-20-git-send-email-eblake@redhat.com> In-Reply-To: <1466721446-27737-1-git-send-email-eblake@redhat.com> References: <1466721446-27737-1-git-send-email-eblake@redhat.com> Subject: [Qemu-devel] [PATCH v3 19/22] block: Split bdrv_merge_limits() from bdrv_refresh_limits() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, kwolf@redhat.com, famz@redhat.com, stefanha@redhat.com, Max Reitz During bdrv_merge_limits(), we were computing initial limits based on another BDS in two places. At first glance, the two computations are not identical (one is doing straight copying, the other is doing merging towards or away from zero) - but when you realize that the first round is starting with all-0 memory, all of the merging happens to work. Factoring out the merging makes it easier to track how two BDS limits are merged, in case we have future reasons to merge in even more limits. Signed-off-by: Eric Blake --- v3: Split raw block driver changes to its own patch, make new function static v2: new patch --- block/io.c | 31 +++++++++++++------------------ 1 file changed, 13 insertions(+), 18 deletions(-) diff --git a/block/io.c b/block/io.c index 0f15d05..69dbbd3 100644 --- a/block/io.c +++ b/block/io.c @@ -67,6 +67,17 @@ static void bdrv_parent_drained_end(BlockDriverState *bs) } } +static void bdrv_merge_limits(BlockLimits *dst, const BlockLimits *src) +{ + dst->opt_transfer = MAX(dst->opt_transfer, src->opt_transfer); + dst->max_transfer = MIN_NON_ZERO(dst->max_transfer, src->max_transfer); + dst->opt_mem_alignment = MAX(dst->opt_mem_alignment, + src->opt_mem_alignment); + dst->min_mem_alignment = MAX(dst->min_mem_alignment, + src->min_mem_alignment); + dst->max_iov = MIN_NON_ZERO(dst->max_iov, src->max_iov); +} + void bdrv_refresh_limits(BlockDriverState *bs, Error **errp) { BlockDriver *drv = bs->drv; @@ -88,11 +99,7 @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp) error_propagate(errp, local_err); return; } - bs->bl.opt_transfer = bs->file->bs->bl.opt_transfer; - bs->bl.max_transfer = bs->file->bs->bl.max_transfer; - bs->bl.min_mem_alignment = bs->file->bs->bl.min_mem_alignment; - bs->bl.opt_mem_alignment = bs->file->bs->bl.opt_mem_alignment; - bs->bl.max_iov = bs->file->bs->bl.max_iov; + bdrv_merge_limits(&bs->bl, &bs->file->bs->bl); } else { bs->bl.min_mem_alignment = 512; bs->bl.opt_mem_alignment = getpagesize(); @@ -107,19 +114,7 @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp) error_propagate(errp, local_err); return; } - bs->bl.opt_transfer = MAX(bs->bl.opt_transfer, - bs->backing->bs->bl.opt_transfer); - bs->bl.max_transfer = MIN_NON_ZERO(bs->bl.max_transfer, - bs->backing->bs->bl.max_transfer); - bs->bl.opt_mem_alignment = - MAX(bs->bl.opt_mem_alignment, - bs->backing->bs->bl.opt_mem_alignment); - bs->bl.min_mem_alignment = - MAX(bs->bl.min_mem_alignment, - bs->backing->bs->bl.min_mem_alignment); - bs->bl.max_iov = - MIN(bs->bl.max_iov, - bs->backing->bs->bl.max_iov); + bdrv_merge_limits(&bs->bl, &bs->backing->bs->bl); } /* Then let the driver override it */ -- 2.5.5