The nvme driver checked the queue state on every IO so this path could
be used to flush out entered requests to a failed completion. The code
even mentions in comments that we shouldn't have to do this, so let's
not do it.
Use the blk-mq's tag iterator to end all entered requests when the queue
isn't going to be restarted so the IO path doesn't have to deal with
these conditions.
Signed-off-by: Keith Busch <keith.busch@xxxxxxxxx>
---
drivers/nvme/host/pci.c | 45 +++++++++++++++++++++++++++++----------------
1 file changed, 29 insertions(+), 16 deletions(-)
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index f54718b63637..398c6333cf77 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -918,13 +918,6 @@ static blk_status_t nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
struct nvme_command cmnd;
blk_status_t ret;
- /*
- * We should not need to do this, but we're still using this to
- * ensure we can drain requests on a dying queue.
- */
- if (unlikely(!test_bit(NVMEQ_ENABLED, &nvmeq->flags)))
- return BLK_STS_IOERR;
-
ret = nvme_setup_cmd(ns, req, &cmnd);
if (ret)
return ret;
@@ -1403,10 +1396,6 @@ static int nvme_suspend_queue(struct nvme_queue *nvmeq)
{
if (!test_and_clear_bit(NVMEQ_ENABLED, &nvmeq->flags))
return 1;
-
- /* ensure that nvme_queue_rq() sees NVMEQ_ENABLED cleared */
- mb();
-
nvmeq->dev->online_queues--;
if (!nvmeq->qid && nvmeq->dev->ctrl.admin_q)
blk_mq_quiesce_queue(nvmeq->dev->ctrl.admin_q);
@@ -1616,15 +1605,29 @@ static const struct blk_mq_ops nvme_mq_ops = {
.poll = nvme_poll,
};
+static bool nvme_fail_queue_request(struct request *req, void *data, bool reserved)
+{
+ struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+ struct nvme_queue *nvmeq = iod->nvmeq;
+
+ if (!test_bit(NVMEQ_ENABLED, &nvmeq->flags))
+ blk_mq_end_request(req, BLK_STS_IOERR);
+ return true;
+}
+
static void nvme_dev_remove_admin(struct nvme_dev *dev)
{
if (dev->ctrl.admin_q && !blk_queue_dying(dev->ctrl.admin_q)) {
/*
* If the controller was reset during removal, it's possible
- * user requests may be waiting on a stopped queue. Start the
- * queue to flush these to completion.
+ * user requests may be waiting on a stopped queue. End all
+ * entered requests after preventing new requests from
+ * entering.
*/
- blk_mq_unquiesce_queue(dev->ctrl.admin_q);
+ blk_set_queue_dying(dev->ctrl.admin_q);
+ blk_mq_tagset_busy_iter(&dev->admin_tagset,
+ nvme_fail_queue_request,
+ NULL);
blk_cleanup_queue(dev->ctrl.admin_q);
blk_mq_free_tag_set(&dev->admin_tagset);
}
@@ -2435,6 +2438,14 @@ static void nvme_pci_disable(struct nvme_dev *dev)
}
}
+static void nvme_fail_requests(struct nvme_dev *dev)
+{
+ if (!dev->ctrl.tagset)
+ return;
+ blk_mq_tagset_busy_iter(dev->ctrl.tagset, nvme_fail_queue_request,
+ NULL);
+}
+
static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
{
bool dead = true;
@@ -2475,11 +2486,11 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
/*
* The driver will not be starting up queues again if shutting down so
- * must flush all entered requests to their failed completion to avoid
+ * must end all entered requests to their failed completion to avoid
* deadlocking blk-mq hot-cpu notifier.
*/
if (shutdown)
- nvme_start_queues(&dev->ctrl);
+ nvme_fail_requests(dev);
mutex_unlock(&dev->shutdown_lock);
}
@@ -2624,6 +2635,8 @@ static void nvme_reset_work(struct work_struct *work)
nvme_remove_namespaces(&dev->ctrl);
new_state = NVME_CTRL_ADMIN_ONLY;
} else {
+ /* Fail requests that entered an hctx that no longer exists */
+ nvme_fail_requests(dev);
nvme_start_queues(&dev->ctrl);
nvme_wait_freeze(&dev->ctrl);
/* hit this only when allocate tagset fails */
--
2.14.4
