From mboxrd@z Thu Jan 1 00:00:00 1970 From: bart.vanassche@sandisk.com (Bart Van Assche) Date: Wed, 28 Sep 2016 17:02:50 -0700 Subject: [PATCH v2 3/7] [RFC] nvme: Use BLK_MQ_S_STOPPED instead of QUEUE_FLAG_STOPPED in blk-mq code In-Reply-To: References: Message-ID: <9faa7607-eb3e-ce41-b09e-1e10492a5f45@sandisk.com> Make nvme_requeue_req() check BLK_MQ_S_STOPPED instead of QUEUE_FLAG_STOPPED. Remove the QUEUE_FLAG_STOPPED manipulations that became superfluous because of this change. This patch fixes a race condition: using queue_flag_clear_unlocked() is not safe if any other function that manipulates the queue flags can be called concurrently, e.g. blk_cleanup_queue(). Untested. Signed-off-by: Bart Van Assche Cc: Keith Busch Cc: Christoph Hellwig Cc: Sagi Grimberg --- drivers/nvme/host/core.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 4669c05..d791fba 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -205,7 +205,7 @@ void nvme_requeue_req(struct request *req) blk_mq_requeue_request(req); spin_lock_irqsave(req->q->queue_lock, flags); - if (!blk_queue_stopped(req->q)) + if (!blk_mq_queue_stopped(req->q)) blk_mq_kick_requeue_list(req->q); spin_unlock_irqrestore(req->q->queue_lock, flags); } @@ -2080,10 +2080,6 @@ void nvme_stop_queues(struct nvme_ctrl *ctrl) mutex_lock(&ctrl->namespaces_mutex); list_for_each_entry(ns, &ctrl->namespaces, list) { - spin_lock_irq(ns->queue->queue_lock); - queue_flag_set(QUEUE_FLAG_STOPPED, ns->queue); - spin_unlock_irq(ns->queue->queue_lock); - blk_mq_cancel_requeue_work(ns->queue); blk_mq_stop_hw_queues(ns->queue); } @@ -2097,7 +2093,6 @@ void nvme_start_queues(struct nvme_ctrl *ctrl) mutex_lock(&ctrl->namespaces_mutex); list_for_each_entry(ns, &ctrl->namespaces, list) { - queue_flag_clear_unlocked(QUEUE_FLAG_STOPPED, ns->queue); blk_mq_start_stopped_hw_queues(ns->queue, true); blk_mq_kick_requeue_list(ns->queue); } -- 2.10.0