For some HBAs, particularly SAS HBAs, there is no reason to
allocate a PRD buffer, since it is not used. Add a flag
to prevent its allocation.
Signed-off-by: Brian King <brking@xxxxxxxxxx>
---
drivers/scsi/libata-core.c | 11 +++++++----
include/linux/libata.h | 1 +
2 files changed, 8 insertions(+), 4 deletions(-)
diff -puN include/linux/libata.h~libata_no_prd include/linux/libata.h
--- libata-dev/include/linux/libata.h~libata_no_prd 2006-02-03 12:37:32.000000000 -0600
+++ libata-dev-bjking1/include/linux/libata.h 2006-02-03 12:37:32.000000000 -0600
@@ -161,6 +161,7 @@ enum {
ATA_FLAG_PIO_LBA48 = (1 << 13), /* Host DMA engine is LBA28 only */
ATA_FLAG_IRQ_MASK = (1 << 14), /* Mask IRQ in PIO xfers */
+ ATA_FLAG_NO_PRD = (1 << 15), /* No PRD to allocate */
ATA_QCFLAG_ACTIVE = (1 << 1), /* cmd not yet ack'd to scsi lyer */
ATA_QCFLAG_SG = (1 << 3), /* have s/g table? */
diff -puN drivers/scsi/libata-core.c~libata_no_prd drivers/scsi/libata-core.c
--- libata-dev/drivers/scsi/libata-core.c~libata_no_prd 2006-02-03 12:37:32.000000000 -0600
+++ libata-dev-bjking1/drivers/scsi/libata-core.c 2006-02-03 12:37:32.000000000 -0600
@@ -4644,9 +4644,11 @@ int ata_port_start (struct ata_port *ap)
struct device *dev = ap->dev;
int rc;
- ap->prd = dma_alloc_coherent(dev, ATA_PRD_TBL_SZ, &ap->prd_dma, GFP_KERNEL);
- if (!ap->prd)
- return -ENOMEM;
+ if ((ap->flags & ATA_FLAG_NO_PRD) == 0) {
+ ap->prd = dma_alloc_coherent(dev, ATA_PRD_TBL_SZ, &ap->prd_dma, GFP_KERNEL);
+ if (!ap->prd)
+ return -ENOMEM;
+ }
rc = ata_pad_alloc(ap, dev);
if (rc) {
@@ -4676,7 +4678,8 @@ void ata_port_stop (struct ata_port *ap)
{
struct device *dev = ap->dev;
- dma_free_coherent(dev, ATA_PRD_TBL_SZ, ap->prd, ap->prd_dma);
+ if ((ap->flags & ATA_FLAG_NO_PRD) == 0)
+ dma_free_coherent(dev, ATA_PRD_TBL_SZ, ap->prd, ap->prd_dma);
ata_pad_free(ap, dev);
}
_
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