libata: update ->data_xfer hook for ATAPI

Depending on how many bytes are transferred as a unit, PIO data
transfer may consume more bytes than requested.  Knowing how much
data is consumed is necessary to determine how much is left for
draining.  This patch update ->data_xfer such that it returns the
number of consumed bytes.

While at it, it also makes the following changes.

* s/adev/dev/
* use READ/WRITE constants for rw indication
* misc clean ups

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 6 insertions, 5 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 03afcd63202d..7fa96cb4f6db 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -701,7 +701,8 @@ struct ata_port_operations {
         void (*bmdma_setup) (struct ata_queued_cmd *qc);
         void (*bmdma_start) (struct ata_queued_cmd *qc);
 
-        void (*data_xfer) (struct ata_device *, unsigned char *, unsigned int, int);
+        unsigned int (*data_xfer) (struct ata_device *dev, unsigned char *buf,
+                                   unsigned int buflen, int rw);
 
         int (*qc_defer) (struct ata_queued_cmd *qc);
         void (*qc_prep) (struct ata_queued_cmd *qc);
@@ -881,10 +882,10 @@ extern void ata_exec_command(struct ata_port *ap, const struct ata_taskfile *tf)
 extern int ata_port_start(struct ata_port *ap);
 extern int ata_sff_port_start(struct ata_port *ap);
 extern irqreturn_t ata_interrupt(int irq, void *dev_instance);
-extern void ata_data_xfer(struct ata_device *adev, unsigned char *buf,
-                          unsigned int buflen, int write_data);
-extern void ata_data_xfer_noirq(struct ata_device *adev, unsigned char *buf,
-                                unsigned int buflen, int write_data);
+extern unsigned int ata_data_xfer(struct ata_device *dev,
+                        unsigned char *buf, unsigned int buflen, int rw);
+extern unsigned int ata_data_xfer_noirq(struct ata_device *dev,
+                        unsigned char *buf, unsigned int buflen, int rw);
 extern int ata_std_qc_defer(struct ata_queued_cmd *qc);
 extern void ata_dumb_qc_prep(struct ata_queued_cmd *qc);
 extern void ata_qc_prep(struct ata_queued_cmd *qc);