From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49804) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V44uH-0002DP-1B for qemu-devel@nongnu.org; Tue, 30 Jul 2013 04:03:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V44u7-0007Ny-AI for qemu-devel@nongnu.org; Tue, 30 Jul 2013 04:03:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:31520) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V44kR-0004fh-2G for qemu-devel@nongnu.org; Tue, 30 Jul 2013 03:53:35 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r6U7rYZ0007700 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 30 Jul 2013 03:53:34 -0400 From: Fam Zheng Date: Tue, 30 Jul 2013 15:52:53 +0800 Message-Id: <1375170777-31457-4-git-send-email-famz@redhat.com> In-Reply-To: <1375170777-31457-1-git-send-email-famz@redhat.com> References: <1375170777-31457-1-git-send-email-famz@redhat.com> Subject: [Qemu-devel] [PATCH v2 3/7] block: implement reference count for BlockDriverState List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, jcody@redhat.com, famz@redhat.com, stefanha@redhat.com 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 --- block.c | 22 ++++++++++++++++++++++ include/block/block.h | 2 ++ include/block/block_int.h | 1 + 3 files changed, 25 insertions(+) diff --git a/block.c b/block.c index c77cfd1..f86f14c 100644 --- a/block.c +++ b/block.c @@ -306,6 +306,7 @@ BlockDriverState *bdrv_new(const char *device_name) bdrv_iostatus_disable(bs); notifier_list_init(&bs->close_notifiers); notifier_with_return_list_init(&bs->before_write_notifiers); + bs->refcnt = 1; return bs; } @@ -1518,6 +1519,9 @@ 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; @@ -4392,6 +4396,24 @@ 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_close(bs); + 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 742fce5..b33ef62 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -356,6 +356,8 @@ 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 e45f2a0..1f85cfb 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -294,6 +294,7 @@ 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; -- 1.8.3.4