From 414c2ec3585408a5c7b458664db180e91480bb03 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 5 Jun 2017 14:38:51 +0200 Subject: [PATCH] block: access quiesce_counter with atomic ops Reviewed-by: Stefan Hajnoczi Reviewed-by: Alberto Garcia Signed-off-by: Paolo Bonzini Message-Id: <20170605123908.18777-3-pbonzini@redhat.com> Signed-off-by: Fam Zheng --- 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 98c690f306..70643df494 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 49f2ebb95a..1824e0e135 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; };