From 850d54a2a9cf16f589f4aa40272515294671633f Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 5 Jun 2017 14:38:55 +0200 Subject: [PATCH] block: access io_plugged with atomic ops Reviewed-by: Stefan Hajnoczi Signed-off-by: Paolo Bonzini Message-Id: <20170605123908.18777-7-pbonzini@redhat.com> Signed-off-by: Fam Zheng --- 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 4a598299a9..bb1c9c5432 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 cf544b7f31..091b5d361c 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; -- 2.11.4.GIT