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 <bart.vanassche@xxxxxxxxxxx>
Cc: Keith Busch <keith.busch@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Sagi Grimberg <sagi@xxxxxxxxxxx>
---
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 fe15d94..45dd237 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -201,13 +201,7 @@ static struct nvme_ns *nvme_get_ns_from_disk(struct gendisk *disk)
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);
@@ -2078,13 +2072,8 @@ 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);
@@ -2095,7 +2084,6 @@ 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);
}
--
2.10.1
--
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