This is a note to let you know that I've just added the patch titled
nvme-loop: flush off pending I/O while shutting down loop controller
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nvme-loop-flush-off-pending-i-o-while-shutting-down-.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 17c1f21596bedadebff06f58a0969ef95c49cdd8
Author: Nilay Shroff <nilay@xxxxxxxxxxxxx>
Date: Wed Oct 16 08:33:14 2024 +0530
nvme-loop: flush off pending I/O while shutting down loop controller
[ 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>
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)
