Re: [PATCH] libata-eh copy result_tf flags from outgoing tf

[Mark Lord <liml@rtr.ca>]

Tejun Heo wrote:
> Mark Lord wrote:
>> Fix mis-reporting of NCQ errors by copying tf->flags to result_tf->flags
>> in libata-eh.  This allows ata_gen_ata_sense() to report the failed
>> block number correctly to SCSI after a media error during NCQ.
>>
>> This patch may also be a candidate for backporting to earlier kernels.
>> Without this fix, SCSI will fail I/O on the entire request rather
>> than just the bad sector.  That can be bad for a request that was
>> merged from many independent read reads from different tasks.
>>
>> Signed-off-by: Mark Lord <mlord@pobox.com>
>>
>> --- upstream/drivers/ata/libata-eh.c    2008-04-18 09:31:15.000000000 
>> -0400
>> +++ linux/drivers/ata/libata-eh.c    2008-04-23 16:25:38.000000000 -0400
>> @@ -1402,6 +1402,7 @@
>>     /* we've got the perpetrator, condemn it */
>>     qc = __ata_qc_from_tag(ap, tag);
>>     memcpy(&qc->result_tf, &tf, sizeof(tf));
>> +    qc->result_tf.flags = qc->tf.flags;
> 
> Maybe it's better to set ATA_TFLAG_LBA48 | ATA_TFLAG_ISADDR | 
> ATA_TFLAG_DEVICE?  After all, all fields are available after that memcpy().
..

I just did it the same way as the standard version in libata-core does it.
In this particular case, we know it was NCQ, so we know that the original
tf->flags have (ATA_TFLAG_LBA48|ATA_TFLAG_ISADDR|ATA_TFLAG_DEVICE) set.

I figured better to copy than just overwrite, because new flags might come along.

Cheers