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@xxxxxxxxx>
---
drivers/ata/libata-core.c | 15 +++++++--------
1 files changed, 7 insertions(+), 8 deletions(-)
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 5d21cc7..8478fd6 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4487,7 +4487,6 @@ 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);
@@ -4759,11 +4758,9 @@ 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;
@@ -4792,7 +4789,6 @@ 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;
@@ -4852,6 +4848,7 @@ static int ata_sg_setup(struct ata_queued_cmd *qc)
skip_map:
qc->n_elem = n_elem;
+ qc->flags |= ATA_QCFLAG_DMAMAP;
return 0;
}
@@ -5915,12 +5912,15 @@ 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)) {
@@ -5938,7 +5938,6 @@ 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);
--
1.5.2.4
-
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