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Commit 36a7e993 authored by Jon Derrick's avatar Jon Derrick Committed by Jens Axboe
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NVMe: Memory barrier before queue_count is incremented 



Protects against reordering and/or preempting which would allow the
kthread to access the queue descriptor before it is set up

Signed-off-by: default avatarJon Derrick <jonathan.derrick@intel.com>
Acked-by: default avatarKeith Busch <keith.busch@intel.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 4cc06521

drivers/block/nvme-core.c

+4 −1
Original line number Diff line number Diff line
@@ -1453,9 +1453,12 @@ static struct nvme_queue *nvme_alloc_queue(struct nvme_dev *dev, int qid, 
	nvmeq->q_db = &dev->dbs[qid * 2 * dev->db_stride];

	nvmeq->q_depth = depth;

	nvmeq->qid = qid;

	dev->queue_count++;

	dev->queues[qid] = nvmeq;



	/* make sure queue descriptor is set before queue count, for kthread */

	mb();

	dev->queue_count++;



	return nvmeq;



 free_cqdma: