[PATCH 0/2] Handle update hardware queues and queue freeze more carefully

[Daniel Wagner]

Hi,

this is a followup on the crash I reported in

  https://lore.kernel.org/linux-block/20210608183339.70609-1-dwagner@suse.de/

By moving the hardware check up the crash was gone. Unfortuntatly, I
don't understand why this fixes the crash. The per-cpu access is
crashing but I can't see why the blk_mq_update_nr_hw_queues() is
fixing this problem.

Even though I can't explain why it fixes it, I think it makes sense to
update the hardware queue mapping bevore we recreate the IO
queues. Thus I avoided in the commit message to say it fixes
something.

Also during testing I observed the we hang indivinetly in
blk_mq_freeze_queue_wait(). Again I can't explain why we get stuck
there but given a common pattern for the nvme_wait_freeze() is to use
it with a timeout I think the timeout should be used too :)

Anyway, someone with more undertanding of the stack can explain the
problems.

Thanks,
Daniel


Daniel Wagner (2):
  nvme-fc: Update hardware queues before using them
  nvme-fc: Wait with a timeout for queue to freeze

 drivers/nvme/host/fc.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

-- 
2.29.2