Re: [PATCH v2] scsi: ufs: core: Quiesce SCSI devices instead of host tagset during error handling

[Stanley Jhu <stanleyjhu@google.com>]

On Sat, 12 Sep 2026 10:03:24 +0000, sashiko-bot@kernel.org wrote:
> Will this loop skip devices that are in the process of being removed, leaving
> their request queues permanently quiesced?

Confirmed.

The old code unquiesced every queue in the tagset, including queues of
devices already being removed: a queue leaves set->tag_list only in
blk_mq_exit_queue(), which runs after device_del().
shost_for_each_device() skips those devices instead, because
scsi_device_get() fails once a device is in SDEV_CANCEL or SDEV_DEL. Their
queues then stay quiesced forever, and sd_shutdown() -> sd_sync_cache()
hangs in blk_execute_rq() with no timeout, since the request is never
started.

v3 takes a different approach. It keeps blk_mq_quiesce_tagset() as before
and only unquiesces hba->host->pseudo_sdev on top of it, so internal
commands stay dispatchable while the logical units remain quiesced. Clock
scaling and ufshcd_pause_command_processing() are unchanged.

Bart's Reviewed-by is dropped from v3 since the implementation changed.

Thanks,
Stanley Jhu