From a6eaa8849f92a40f8894d6d0dcab2c16243aaf20 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Fri, 28 Oct 2016 17:23:40 -0700 Subject: [PATCH] nvme: Use BLK_MQ_S_STOPPED instead of QUEUE_FLAG_STOPPED in blk-mq code 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. Change blk_queue_stopped() tests into blk_mq_queue_stopped(). 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(). Signed-off-by: Bart Van Assche Cc: Keith Busch Cc: Sagi Grimberg Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe --- drivers/nvme/host/core.c | 16 ++-------------- 1 file changed, 2 insertions(+), 14 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 75565b5951d9..ef34f2f3566a 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -201,13 +201,7 @@ fail: void nvme_requeue_req(struct request *req) { - unsigned long flags; - - blk_mq_requeue_request(req, false); - spin_lock_irqsave(req->q->queue_lock, flags); - if (!blk_queue_stopped(req->q)) - blk_mq_kick_requeue_list(req->q); - spin_unlock_irqrestore(req->q->queue_lock, flags); + blk_mq_requeue_request(req, !blk_mq_queue_stopped(req->q)); } EXPORT_SYMBOL_GPL(nvme_requeue_req); @@ -2076,13 +2070,8 @@ void nvme_stop_queues(struct nvme_ctrl *ctrl) struct nvme_ns *ns; 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); - + list_for_each_entry(ns, &ctrl->namespaces, list) blk_mq_quiesce_queue(ns->queue); - } mutex_unlock(&ctrl->namespaces_mutex); } EXPORT_SYMBOL_GPL(nvme_stop_queues); @@ -2093,7 +2082,6 @@ 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); } -- 2.20.1