Tejun Heo wrote:
> Robert Hancock wrote:
>> We need to run any DMA command with result taskfile requested in ADMA mode
>> when the port is in ADMA mode, otherwise it may try to use the legacy DMA engine
>> in ADMA mode which is not allowed. Enforce this with BUG_ON() since data
>> corruption could potentially result if this happened. Also WARN_ON() if we try
>> and send result taskfile commands while NCQ commands are still active, since the
>> hardware doesn't allow this.
>>
>> Signed-off-by: Robert Hancock <hancockr@xxxxxxx>
>>
>> @@ -1425,9 +1427,17 @@
>> + /* We can't handle result taskfile with NCQ commands active, since
>> + retrieving the taskfile switches us out of ADMA mode and would abort
>> + existing commands. */
>> + WARN_ON((qc->flags & ATA_QCFLAG_RESULT_TF) &&
>> + (qc->ap->qc_allocated & ~(1 << qc->tag)));
>
> I owe an apology here. ap->qc_allocated & ~(1 << qc->tag) test isn't
> correct. Sorry. qc deferring happens after qc is allocated so the
> condition can trigger (although it should be rare) even when nothing is
> going wrong, so I guess it should be WARN_ON((qc->flags &
> ATA_QCFLAG_RESULT_TF) && link->sactive).
Or, just make the assumption clear by not allowing NCQ w/ RESULT_TF at all.
if (unlikely(qc->tf.protocol == ATA_PROT_NCQ &&
(qc->flags & ATA_QCFLAG_RESULT_TF)) {
ata_dev_printk(qc->dev, KERN_ERR,
"NCQ w/ RESULT_TF not allowed\n");
return AC_ERR_SYSTEM;
}
Thanks.
--
tejun
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