[PATCH] libata: separate out rw ATA taskfile building into ata_build_rw_tf()

Separate out rw ATA taskfile building from ata_scsi_rw_xlat() into
ata_build_rw_tf().  This will be used to improve media error handling.

Signed-off-by: Tejun Heo <htejun@gmail.com>
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index ca6f36c..60576b1 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -51,7 +51,9 @@
 extern int atapi_dmadir;
 extern int libata_fua;
 extern struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev);
-extern int ata_rwcmd_protocol(struct ata_queued_cmd *qc);
+extern int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev,
+			   u64 block, u32 n_block, unsigned int tf_flags,
+			   unsigned int tag);
 extern u64 ata_tf_read_block(struct ata_taskfile *tf, struct ata_device *dev);
 extern void ata_dev_disable(struct ata_device *dev);
 extern void ata_port_flush_task(struct ata_port *ap);