scsi: core: Clear UNIT ATTENTION conditions with TEST UNIT READY

Some targets, e.g. BIWIN BWU2A05* UFS devices, fail to clear power-on or
reset UNIT ATTENTION conditions on WRITE commands while clearing these
on commands like TEST UNIT READY, READ, and SYNCHRONIZE CACHE.

Add scsi_eh_clear_ua() to scsi_eh_ready_devs() ahead of device reset so
that the error handler sends TEST UNIT READY to consume a stuck UNIT
ATTENTION and verifies with a follow-up TEST UNIT READY that the
condition cleared before requeueing affected commands. Allow a few
additional TEST UNIT READY attempts for queued UNIT ATTENTION conditions
and busy devices, delay retries, and honor the error handler
deadline. Save and restore scmd->sense_buffer across scsi_send_eh_cmnd()
so that the original sense data remains intact while filtering work_q
and if retries are later exhausted. Log a rate-limited message when a
persistent UNIT ATTENTION is cleared to make it possible to identify
misbehaving devices.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/444e78b0fa892e8854bee89f341824d67000d968.1793400000.git.bvanassche@acm.org
Signed-off-by: Martin K. Petersen (Oracle) <mkp@kernel.org>

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