From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42062) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d8pIM-0001Mb-2J for qemu-devel@nongnu.org; Thu, 11 May 2017 10:42:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d8pIL-00049A-CK for qemu-devel@nongnu.org; Thu, 11 May 2017 10:42:22 -0400 From: Paolo Bonzini Date: Thu, 11 May 2017 16:41:52 +0200 Message-Id: <20170511144208.24075-3-pbonzini@redhat.com> In-Reply-To: <20170511144208.24075-1-pbonzini@redhat.com> References: <20170511144208.24075-1-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH 02/18] block: access quiesce_counter with atomic ops List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: famz@redhat.com, stefanha@redhat.com, qemu-block@nongnu.org Reviewed-by: Stefan Hajnoczi Signed-off-by: Paolo Bonzini --- block/io.c | 4 ++-- include/block/block_int.h | 1 + 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/block/io.c b/block/io.c index a0de60acbc..3204e08c8f 100644 --- a/block/io.c +++ b/block/io.c @@ -241,7 +241,7 @@ void bdrv_drained_begin(BlockDriverState *bs) return; } - if (!bs->quiesce_counter++) { + if (atomic_fetch_inc(&bs->quiesce_counter) == 0) { aio_disable_external(bdrv_get_aio_context(bs)); bdrv_parent_drained_begin(bs); } @@ -252,7 +252,7 @@ void bdrv_drained_begin(BlockDriverState *bs) void bdrv_drained_end(BlockDriverState *bs) { assert(bs->quiesce_counter > 0); - if (--bs->quiesce_counter > 0) { + if (atomic_fetch_dec(&bs->quiesce_counter) > 1) { return; } diff --git a/include/block/block_int.h b/include/block/block_int.h index eb90c529cd..b529f894be 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -623,6 +623,7 @@ struct BlockDriverState { /* do we need to tell the quest if we have a volatile write cache? */ int enable_write_cache; + /* Accessed with atomic ops. */ int quiesce_counter; }; -- 2.12.2