libata: minor whitespace, comment, debug message updates
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 03b7a6d..d67c3fc 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -589,7 +589,8 @@
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 @@
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 @@
/* 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 @@
tf->device |= (block >> 24) & 0xf;
}
-
+
qc->nsect = n_block;
tf->nsect = n_block & 0xff;
@@ -731,23 +740,23 @@
/* 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;
