From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51556) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dDvgj-0004gG-HK for qemu-devel@nongnu.org; Thu, 25 May 2017 12:32:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dDvgi-0003ia-S6 for qemu-devel@nongnu.org; Thu, 25 May 2017 12:32:37 -0400 From: Paolo Bonzini Date: Thu, 25 May 2017 18:32:09 +0200 Message-Id: <20170525163225.29954-3-pbonzini@redhat.com> In-Reply-To: <20170525163225.29954-1-pbonzini@redhat.com> References: <20170525163225.29954-1-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: qemu-block@nongnu.org, famz@redhat.com, stefanha@redhat.com Reviewed-by: Stefan Hajnoczi Reviewed-by: Alberto Garcia 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 80a3a8c..7d31946 100644 --- a/block/io.c +++ b/block/io.c @@ -240,7 +240,7 @@ 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); } @@ -251,7 +251,7 @@ 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 c71492a..4af44df 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -637,6 +637,7 @@ 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; }; -- 1.8.3.1