From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58710) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V4BH9-0002GG-Ff for qemu-devel@nongnu.org; Tue, 30 Jul 2013 10:51:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V4BH3-0002Ob-BM for qemu-devel@nongnu.org; Tue, 30 Jul 2013 10:51:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:62779) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V4BH3-0002OX-3f for qemu-devel@nongnu.org; Tue, 30 Jul 2013 10:51:41 -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 r6UEpe8I001088 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 30 Jul 2013 10:51:40 -0400 Date: Tue, 30 Jul 2013 10:51:36 -0400 From: Jeff Cody Message-ID: <20130730145136.GD19718@localhost.localdomain> References: <1375170777-31457-1-git-send-email-famz@redhat.com> <1375170777-31457-4-git-send-email-famz@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1375170777-31457-4-git-send-email-famz@redhat.com> Subject: Re: [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: Fam Zheng Cc: kwolf@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com On Tue, Jul 30, 2013 at 03:52:53PM +0800, Fam Zheng wrote: > 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); The bdrv_close() here is redundant. > + } > +} > + > 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 >