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libata: don't check whether to use DMA or not for no data commands

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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>
This commit is contained in:
Tejun Heo 2008-06-17 12:36:26 +09:00 committed by Jeff Garzik
parent d799e083a8
commit 5895ef9a5b
3 changed files with 10 additions and 12 deletions
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4
drivers/ata/libata-core.c
View File

@ -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;

16
drivers/ata/libata-scsi.c
View File

@ -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;

2
drivers/ata/libata.h
View File

@ -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);