From: Paolo Bonzini <pbonz...@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Message-Id: <20170605123908.18777-7-pbonz...@redhat.com>
Signed-off-by: Fam Zheng <f...@redhat.com>
---
block/io.c | 4 ++--
include/block/block_int.h | 8 +++++---
2 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/block/io.c b/block/io.c
index 4a59829..bb1c9c5 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2645,7 +2645,7 @@ void bdrv_io_plug(BlockDriverState *bs)
bdrv_io_plug(child->bs);
}
- if (bs->io_plugged++ == 0) {
+ if (atomic_fetch_inc(&bs->io_plugged) == 0) {
BlockDriver *drv = bs->drv;
if (drv && drv->bdrv_io_plug) {
drv->bdrv_io_plug(bs);
@@ -2658,7 +2658,7 @@ void bdrv_io_unplug(BlockDriverState *bs)
BdrvChild *child;
assert(bs->io_plugged);
- if (--bs->io_plugged == 0) {
+ if (atomic_fetch_dec(&bs->io_plugged) == 1) {
BlockDriver *drv = bs->drv;
if (drv && drv->bdrv_io_unplug) {
drv->bdrv_io_unplug(bs);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index cf544b7..091b5d3 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -611,9 +611,6 @@ struct BlockDriverState {
uint64_t write_threshold_offset;
NotifierWithReturn write_threshold_notifier;
- /* counter for nested bdrv_io_plug */
- unsigned io_plugged;
-
QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
CoQueue flush_queue; /* Serializing flush queue */
bool active_flush_req; /* Flush request in flight? */
@@ -639,6 +636,11 @@ struct BlockDriverState {
*/
bool wakeup;
+ /* counter for nested bdrv_io_plug.
+ * Accessed with atomic ops.
+ */
+ unsigned io_plugged;
+
/* do we need to tell the quest if we have a volatile write cache? */
int enable_write_cache;
--
2.9.4
