[libata scsi] fix read/write translation edge cases
Fix bugs for unlikely edge cases noticed by Douglas Gilbert:
- When READ(6)/WRITE(6) sector count == 0, treat it as 256 sectors
- For other READ(x)/WRITE(x), when sector count == 0, error.
We don't support successfully completing zero-length transfers at
this time.
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index f58311b..4074e78 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -630,11 +630,19 @@
tf->lbah = scsicmd[3];
VPRINTK("ten-byte command\n");
+ if (qc->nsect == 0) /* we don't support length==0 cmds */
+ return 1;
return 0;
}
if (scsicmd[0] == READ_6 || scsicmd[0] == WRITE_6) {
qc->nsect = tf->nsect = scsicmd[4];
+ if (!qc->nsect) {
+ qc->nsect = 256;
+ if (lba48)
+ tf->hob_nsect = 1;
+ }
+
tf->lbal = scsicmd[3];
tf->lbam = scsicmd[2];
tf->lbah = scsicmd[1] & 0x1f; /* mask out reserved bits */
@@ -674,6 +682,8 @@
tf->lbah = scsicmd[7];
VPRINTK("sixteen-byte command\n");
+ if (qc->nsect == 0) /* we don't support length==0 cmds */
+ return 1;
return 0;
}