On 09/20/2018 06:15 PM, Jens Axboe wrote:
>>> When we're comparing the hardware completion mask passed in from the
>>> driver with the internal tag pending mask, we need to account for the
>>> fact that the internal tag is different from the hardware tag. If not,
>>> then we can end up either prematurely completing the internal tag (since
>>> it's not set in the hw mask), or simply flag an error:
>>>
>>> ata2: illegal qc_active transition (100000000->00000001)
>>>
>>> If the internal tag is set, then swap that with the hardware tag in this
>>> case before comparing with what the hardware reports.
>>>
>>> Fixes: 28361c403683 ("libata: add extra internal command")
>>> Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=201151
>>> Cc: stable@xxxxxxxxxxxxxxx
>>> Reported-by: Paul Sbarra <sbarra.paul@xxxxxxxxx>
>>> Tested-by: Paul Sbarra <sbarra.paul@xxxxxxxxx>
>>> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
>>>
>>> ---
>>>
>>> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
>>> index 599e01bcdef2..a9dd4ea7467d 100644
>>> --- a/drivers/ata/libata-core.c
>>> +++ b/drivers/ata/libata-core.c
>>> @@ -5359,10 +5359,20 @@ void ata_qc_complete(struct ata_queued_cmd *qc)
>>> */
>>> int ata_qc_complete_multiple(struct ata_port *ap, u64 qc_active)
>>> {
>>> + u64 done_mask, ap_qc_active = ap->qc_active;
>>> int nr_done = 0;
>>> - u64 done_mask;
>>>
>>> - done_mask = ap->qc_active ^ qc_active;
>>> + /*
>>> + * If the internal tag is set on ap->qc_active, then we care about
>>> + * bit0 on the passed in qc_active mask. Move that bit up to match
>>> + * the internal tag.
>>> + */
>>> + if (ap_qc_active & (1ULL << ATA_TAG_INTERNAL)) {
>>
>> Maybe BIT_ULL(ATA_TAG_INTERNAL)?
>
> Honestly, I had defines like that, since they hide what's going on, whereas
> the above is immediately readable to anyone. If it isn't, they probably
> shouldn't be fiddling with that code :-)
>
> Besides, we don't use that anywhere in libata currently. If someone has
To be precise, BIT() does get used in <linux/ata.h> and once in libata-core.c.
Also some libata drivers do use that macro.
> a good case for why that should change, I'm all ears. But should be
> a separate change.
Not me, I'm not a big fan of the macros either... :-)
MBR, Sergei
