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libata: change ATA_QCFLAG_DMAMAP semantics 

ATA_QCFLAG_DMAMAP was a bit peculiar in that it got set during qc
initialization and cleared if DMA mapping wasn't necessary.  Make it
more straight forward by making the following changes.

* Don't set it during initialization.  Set it after DMA is actually
  mapped.

* Add BUG_ON() to guarantee that there is data to transfer if DMAMAP
  is set.  This always holds for the current code.  The BUG_ON() is
  for docummentation and sanity check.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
hifive-unleashed-5.1
Tejun Heo 2007-12-05 16:43:10 +09:00 committed by Jeff Garzik
parent 001102d785
commit f92a26365a
1 changed files with 7 additions and 8 deletions
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15
drivers/ata/libata-core.c
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@ -4475,7 +4475,6 @@ void ata_sg_clean(struct ata_queued_cmd *qc)
int dir = qc->dma_dir;
void *pad_buf = NULL;
WARN_ON(!(qc->flags & ATA_QCFLAG_DMAMAP));
WARN_ON(sg == NULL);
VPRINTK("unmapping %u sg elements\n", qc->n_elem);
@ -4762,11 +4761,9 @@ void ata_noop_qc_prep(struct ata_queued_cmd *qc) { }
* LOCKING:
* spin_lock_irqsave(host lock)
*/
void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
unsigned int n_elem)
{
qc->flags |= ATA_QCFLAG_DMAMAP;
qc->__sg = sg;
qc->n_elem = n_elem;
qc->orig_n_elem = n_elem;
@ -4795,7 +4792,6 @@ static int ata_sg_setup(struct ata_queued_cmd *qc)
int n_elem, pre_n_elem, dir, trim_sg = 0;
VPRINTK("ENTER, ata%u\n", ap->print_id);
WARN_ON(!(qc->flags & ATA_QCFLAG_DMAMAP));
/* we must lengthen transfers to end on a 32-bit boundary */
qc->pad_len = lsg->length & 3;
@ -4855,6 +4851,7 @@ static int ata_sg_setup(struct ata_queued_cmd *qc)
skip_map:
qc->n_elem = n_elem;
qc->flags |= ATA_QCFLAG_DMAMAP;
return 0;
}
@ -5912,12 +5909,15 @@ void ata_qc_issue(struct ata_queued_cmd *qc)
qc->flags |= ATA_QCFLAG_ACTIVE;
ap->qc_active |= 1 << qc->tag;
/* We guarantee to LLDs that they will have at least one
* non-zero sg if the command is a data command.
*/
BUG_ON(ata_is_data(prot) && (!qc->__sg || !qc->n_elem || !qc->nbytes));
if (ata_is_dma(prot) || (ata_is_pio(prot) &&
(ap->flags & ATA_FLAG_PIO_DMA))) {
(ap->flags & ATA_FLAG_PIO_DMA)))
if (ata_sg_setup(qc))
goto sg_err;
} else
qc->flags &= ATA_QCFLAG_DMAMAP;
/* if device is sleeping, schedule softreset and abort the link */
if (unlikely(qc->dev->flags & ATA_DFLAG_SLEEPING)) {
@ -5935,7 +5935,6 @@ void ata_qc_issue(struct ata_queued_cmd *qc)
return;
sg_err:
qc->flags &= ~ATA_QCFLAG_DMAMAP;
qc->err_mask |= AC_ERR_SYSTEM;
err:
ata_qc_complete(qc);