From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40400) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VHy8d-0004xb-Jr for qemu-devel@nongnu.org; Fri, 06 Sep 2013 11:40:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VHy8X-0005Ca-7v for qemu-devel@nongnu.org; Fri, 06 Sep 2013 11:39:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:22924) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VHy8W-0005CI-VS for qemu-devel@nongnu.org; Fri, 06 Sep 2013 11:39:53 -0400 From: Stefan Hajnoczi Date: Fri, 6 Sep 2013 17:38:43 +0200 Message-Id: <1378481953-23099-13-git-send-email-stefanha@redhat.com> In-Reply-To: <1378481953-23099-1-git-send-email-stefanha@redhat.com> References: <1378481953-23099-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PULL 12/42] block: implement reference count for BlockDriverState List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Fam Zheng , Stefan Hajnoczi , Anthony Liguori From: Fam Zheng Introduce bdrv_ref/bdrv_unref to manage the lifecycle of BlockDriverState. They are unused for now but will used to replace bdrv_delete() later. Signed-off-by: Fam Zheng Signed-off-by: Stefan Hajnoczi --- block.c | 21 +++++++++++++++++++++ include/block/block.h | 2 ++ include/block/block_int.h | 1 + 3 files changed, 24 insertions(+) diff --git a/block.c b/block.c index 0292d1d..a2b6003 100644 --- a/block.c +++ b/block.c @@ -332,6 +332,7 @@ BlockDriverState *bdrv_new(const char *device_name) notifier_with_return_list_init(&bs->before_write_notifiers); qemu_co_queue_init(&bs->throttled_reqs[0]); qemu_co_queue_init(&bs->throttled_reqs[1]); + bs->refcnt = 1; return bs; } @@ -1566,6 +1567,9 @@ static void bdrv_move_feature_fields(BlockDriverState *bs_dest, /* dirty bitmap */ bs_dest->dirty_bitmap = bs_src->dirty_bitmap; + /* reference count */ + bs_dest->refcnt = bs_src->refcnt; + /* job */ bs_dest->in_use = bs_src->in_use; bs_dest->job = bs_src->job; @@ -4297,6 +4301,23 @@ int64_t bdrv_get_dirty_count(BlockDriverState *bs) } } +/* Get a reference to bs */ +void bdrv_ref(BlockDriverState *bs) +{ + bs->refcnt++; +} + +/* Release a previously grabbed reference to bs. + * If after releasing, reference count is zero, the BlockDriverState is + * deleted. */ +void bdrv_unref(BlockDriverState *bs) +{ + assert(bs->refcnt > 0); + if (--bs->refcnt == 0) { + bdrv_delete(bs); + } +} + void bdrv_set_in_use(BlockDriverState *bs, int in_use) { assert(bs->in_use != in_use); diff --git a/include/block/block.h b/include/block/block.h index 6207ff2..f24e1ff 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -355,6 +355,8 @@ int64_t bdrv_get_dirty_count(BlockDriverState *bs); void bdrv_enable_copy_on_read(BlockDriverState *bs); void bdrv_disable_copy_on_read(BlockDriverState *bs); +void bdrv_ref(BlockDriverState *bs); +void bdrv_unref(BlockDriverState *bs); void bdrv_set_in_use(BlockDriverState *bs, int in_use); int bdrv_in_use(BlockDriverState *bs); diff --git a/include/block/block_int.h b/include/block/block_int.h index c3c9c61..b9212b8 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -277,6 +277,7 @@ struct BlockDriverState { BlockDeviceIoStatus iostatus; char device_name[32]; HBitmap *dirty_bitmap; + int refcnt; int in_use; /* users other than guest access, eg. block migration */ QTAILQ_ENTRY(BlockDriverState) list; -- 1.8.3.1