From patchwork Wed Jul 31 10:13:56 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fam Zheng X-Patchwork-Id: 263732 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id E41452C0040 for ; Thu, 1 Aug 2013 01:05:00 +1000 (EST) Received: from localhost ([::1]:55411 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V4XxS-0003Uh-6f for incoming@patchwork.ozlabs.org; Wed, 31 Jul 2013 11:04:58 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43869) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V4Xx8-0003UV-VP for qemu-devel@nongnu.org; Wed, 31 Jul 2013 11:04:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V4TQY-0003GS-WB for qemu-devel@nongnu.org; Wed, 31 Jul 2013 06:14:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:12079) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V4TQY-0003G1-Ky for qemu-devel@nongnu.org; Wed, 31 Jul 2013 06:14:42 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r6VAEggT000498 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 31 Jul 2013 06:14:42 -0400 Received: from T430s.nay.redhat.com ([10.66.6.13]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r6VAEURi001246; Wed, 31 Jul 2013 06:14:39 -0400 From: Fam Zheng To: qemu-devel@nongnu.org Date: Wed, 31 Jul 2013 18:13:56 +0800 Message-Id: <1375265640-27307-4-git-send-email-famz@redhat.com> In-Reply-To: <1375265640-27307-1-git-send-email-famz@redhat.com> References: <1375265640-27307-1-git-send-email-famz@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: kwolf@redhat.com, jcody@redhat.com, famz@redhat.com, stefanha@redhat.com Subject: [Qemu-devel] [PATCH v3 3/7] block: implement reference count for BlockDriverState X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org 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 Reviewed-by: Wenchao Xia --- 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 c77cfd1..8f0d646 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 +4396,23 @@ 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 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;