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authorTejun Heo <tj@kernel.org>2008-06-17 12:36:26 +0900
committerJeff Garzik <jgarzik@redhat.com>2008-06-18 20:27:49 -0400
commit5895ef9a5b746e7cc9ebda50c87fbd11562da0a4 (patch)
tree264ed72edfef60f11260f3227523334b1e1aca80 /drivers
parentd799e083a80b220f3681d7790f11e77d1704022b (diff)
downloadlinux-5895ef9a5b746e7cc9ebda50c87fbd11562da0a4.tar.gz
libata: don't check whether to use DMA or not for no data commands
There's no reason to check whether to use DMA or not for no data commands. Don't do it. While at it, make local variable using_pio in atapi_xlat() set iff ATAPI_PROT_PIO is going to be used and rename ata_check_atapi_dma() to atapi_check_dma() for consistency. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/ata/libata-core.c4
-rw-r--r--drivers/ata/libata-scsi.c16
-rw-r--r--drivers/ata/libata.h2
3 files changed, 10 insertions, 12 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index cc816ca623d..303fc0d2b97 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4297,7 +4297,7 @@ void ata_sg_clean(struct ata_queued_cmd *qc)
}
/**
- * ata_check_atapi_dma - Check whether ATAPI DMA can be supported
+ * atapi_check_dma - Check whether ATAPI DMA can be supported
* @qc: Metadata associated with taskfile to check
*
* Allow low-level driver to filter ATA PACKET commands, returning
@@ -4310,7 +4310,7 @@ void ata_sg_clean(struct ata_queued_cmd *qc)
* RETURNS: 0 when ATAPI DMA can be used
* nonzero otherwise
*/
-int ata_check_atapi_dma(struct ata_queued_cmd *qc)
+int atapi_check_dma(struct ata_queued_cmd *qc)
{
struct ata_port *ap = qc->ap;
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 2e6e1622dc6..57a43649a46 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2343,8 +2343,8 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
{
struct scsi_cmnd *scmd = qc->scsicmd;
struct ata_device *dev = qc->dev;
- int using_pio = (dev->flags & ATA_DFLAG_PIO);
int nodata = (scmd->sc_data_direction == DMA_NONE);
+ int using_pio = !nodata && (dev->flags & ATA_DFLAG_PIO);
unsigned int nbytes;
memset(qc->cdb, 0, dev->cdb_len);
@@ -2362,7 +2362,7 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
ata_qc_set_pc_nbytes(qc);
/* check whether ATAPI DMA is safe */
- if (!using_pio && ata_check_atapi_dma(qc))
+ if (!nodata && !using_pio && atapi_check_dma(qc))
using_pio = 1;
/* Some controller variants snoop this value for Packet
@@ -2402,13 +2402,11 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
qc->tf.lbam = (nbytes & 0xFF);
qc->tf.lbah = (nbytes >> 8);
- if (using_pio || nodata) {
- /* no data, or PIO data xfer */
- if (nodata)
- qc->tf.protocol = ATAPI_PROT_NODATA;
- else
- qc->tf.protocol = ATAPI_PROT_PIO;
- } else {
+ if (nodata)
+ qc->tf.protocol = ATAPI_PROT_NODATA;
+ else if (using_pio)
+ qc->tf.protocol = ATAPI_PROT_PIO;
+ else {
/* DMA data xfer */
qc->tf.protocol = ATAPI_PROT_DMA;
qc->tf.feature |= ATAPI_PKT_DMA;
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 4514283937e..1cf803adbc9 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -106,7 +106,7 @@ extern void ata_sg_clean(struct ata_queued_cmd *qc);
extern void ata_qc_free(struct ata_queued_cmd *qc);
extern void ata_qc_issue(struct ata_queued_cmd *qc);
extern void __ata_qc_complete(struct ata_queued_cmd *qc);
-extern int ata_check_atapi_dma(struct ata_queued_cmd *qc);
+extern int atapi_check_dma(struct ata_queued_cmd *qc);
extern void swap_buf_le16(u16 *buf, unsigned int buf_words);
extern void ata_dev_init(struct ata_device *dev);
extern void ata_link_init(struct ata_port *ap, struct ata_link *link, int pmp);