Albert Lee wrote:
> Tejun Heo wrote:
>> Albert Lee wrote:
>>
>>> -static void ata_pio_sector(struct ata_queued_cmd *qc, int last)
>>> +static void ata_pio_sector(struct ata_queued_cmd *qc, int last, int lock)
>>
>> I think the naming of @lock is a bit confusing here. @clr_hsm_wq or
>> @last_sector, maybe?
>>
>
> How about "irq_handover"? When set to "true", it means the workqueue is going to
> handover the control of the port to the irq handler.
>
>>> + if (lock) {
>>> + tail = 8;
>>> + head = ATA_SECT_SIZE - tail; /* multiple of 8 bytes */
>>> + ap->ops->data_xfer(qc->dev, buf + offset, head, do_write);
>>> + spin_lock_irqsave(ap->lock, irq_flags);
>>> + }
>>> +
>>> + ap->ops->data_xfer(qc->dev, buf + offset + head, tail, do_write);
>>
>> Aieee, we have to transfer the whole last sector while holding the spin
>> lock and IRQ disabled. That's sad but pushing locking into ->data_xfer
>> doesn't sound attractive either. Any better ideas?
>>
>
> Why need to transfer the last sector as a whole?
> Spliting it into 504 (unlocked) + 8 (holding ap->lock) works on my machine...
That would be the cleanest way to do it but I'm not sure whether all
controllers can live with that. If I understand correctly, Some
controllers just have to have the whole transfer done atomically. I
think Alan knows much better about this. Alan?
--
tejun
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