6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nilay Shroff <nilay@xxxxxxxxxxxxx>
[ Upstream commit c199fac88fe7c749f88a0653e9f621b9f5a71cf1 ]
While shutting down loop controller, we first quiesce the admin/IO queue,
delete the admin/IO tag-set and then at last destroy the admin/IO queue.
However it's quite possible that during the window between quiescing and
destroying of the admin/IO queue, some admin/IO request might sneak in
and if that happens then we could potentially encounter a hung task
because shutdown operation can't forward progress until any pending I/O
is flushed off.
This commit helps ensure that before destroying the admin/IO queue, we
unquiesce the admin/IO queue so that any outstanding requests, which are
added after the admin/IO queue is quiesced, are now flushed to its
completion.
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Nilay Shroff <nilay@xxxxxxxxxxxxx>
Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/nvme/target/loop.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/drivers/nvme/target/loop.c b/drivers/nvme/target/loop.c
index 48d5df054cd02..bd61a1b82c4cd 100644
--- a/drivers/nvme/target/loop.c
+++ b/drivers/nvme/target/loop.c
@@ -265,6 +265,13 @@ static void nvme_loop_destroy_admin_queue(struct nvme_loop_ctrl *ctrl)
{
if (!test_and_clear_bit(NVME_LOOP_Q_LIVE, &ctrl->queues[0].flags))
return;
+ /*
+ * It's possible that some requests might have been added
+ * after admin queue is stopped/quiesced. So now start the
+ * queue to flush these requests to the completion.
+ */
+ nvme_unquiesce_admin_queue(&ctrl->ctrl);
+
nvmet_sq_destroy(&ctrl->queues[0].nvme_sq);
nvme_remove_admin_tag_set(&ctrl->ctrl);
}
@@ -297,6 +304,12 @@ static void nvme_loop_destroy_io_queues(struct nvme_loop_ctrl *ctrl)
nvmet_sq_destroy(&ctrl->queues[i].nvme_sq);
}
ctrl->ctrl.queue_count = 1;
+ /*
+ * It's possible that some requests might have been added
+ * after io queue is stopped/quiesced. So now start the
+ * queue to flush these requests to the completion.
+ */
+ nvme_unquiesce_io_queues(&ctrl->ctrl);
}
static int nvme_loop_init_io_queues(struct nvme_loop_ctrl *ctrl)
--
2.43.0
