libata: minor whitespace, comment, debug message updates

diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 03b7a6dd95fe0aadf3dbcb2dcaa69136151dc69b..d67c3fc98f7b392ba681c41c4dd592f4cc32e267 100644 (file)
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -589,7 +589,8 @@ static unsigned int ata_scsi_verify_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
                head  = track % dev->heads;
                sect  = (u32)block % dev->sectors + 1;
 
-               DPRINTK("block[%u] track[%u] cyl[%u] head[%u] sect[%u] \n", (u32)block, track, cyl, head, sect);
+               DPRINTK("block %u track %u cyl %u head %u sect %u\n",
+                       (u32)block, track, cyl, head, sect);
                
                /* Check whether the converted CHS can fit. 
                   Cylinder: 0-65535 
@@ -665,6 +666,10 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
                block |= ((u64)scsicmd[3]);
 
                n_block |= ((u32)scsicmd[4]);
+
+               /* for 6-byte r/w commands, transfer length 0
+                * means 256 blocks of data, not 0 block.
+                */
                if (!n_block)
                        n_block = 256;
        
@@ -692,7 +697,11 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
 
        /* Check and compose ATA command */
        if (!n_block)
-               /* In ATA, sector count 0 means 256 or 65536 sectors, not 0 sectors. */
+               /* For 10-byte and 16-byte SCSI R/W commands, transfer
+                * length 0 means transfer 0 block of data.
+                * However, for ATA R/W commands, sector count 0 means
+                * 256 or 65536 sectors, not 0 sectors as in SCSI.
+                */
                return 1;
 
        if (lba) {
@@ -715,7 +724,7 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
 
                        tf->device |= (block >> 24) & 0xf;
                }
-       
+
                qc->nsect = n_block;
                tf->nsect = n_block & 0xff;
 
@@ -731,23 +740,23 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, u8 *scsicmd)
                /* The request -may- be too large for CHS addressing. */
                if ((block >> 28) || (n_block > 256))
                        return 1;
-                       
+
                /* Convert LBA to CHS */
                track = (u32)block / dev->sectors;
                cyl   = track / dev->heads;
                head  = track % dev->heads;
                sect  = (u32)block % dev->sectors + 1;
 
-               DPRINTK("block[%u] track[%u] cyl[%u] head[%u] sect[%u] \n", 
+               DPRINTK("block %u track %u cyl %u head %u sect %u\n",
                        (u32)block, track, cyl, head, sect);
-               
+
                /* Check whether the converted CHS can fit. 
                   Cylinder: 0-65535 
                   Head: 0-15
                   Sector: 1-255*/
-               if ((cyl >> 16) || (head >> 4) || (sect >> 8) || (!sect)) 
+               if ((cyl >> 16) || (head >> 4) || (sect >> 8) || (!sect))
                        return 1;
-               
+
                qc->nsect = n_block;
                tf->nsect = n_block & 0xff; /* Sector count 0 means 256 sectors */
                tf->lbal = sect;