[SCSI] scsi_scan.c: handle bad inquiry responses

AlanStern · James Bottomley · commit e423ee31db92 · 2007-02-16T10:13:01.000-06:00
A particular USB device has been reporting short inquiry lengths.  The
SCSI code cannot operate properly unless we get an inquiry length of
36 or above (because of the way we parse vendor and product), so
assume at least 36 bytes are valid even if the device reports fewer.
This is wrong, but it's no worse than what we're doing now (using the
garbage beyond the last reported valid byte).

Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: James Bottomley &lt;James.Bottomley@SteelEye.com&gt;
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
@@ -654,6 +654,19 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 	 * short INQUIRY), an abort here prevents any further use of the
 	 * device, including spin up.
 	 *
+	 * On the whole, the best approach seems to be to assume the first
+	 * 36 bytes are valid no matter what the device says.  That's
+	 * better than copying < 36 bytes to the inquiry-result buffer
+	 * and displaying garbage for the Vendor, Product, or Revision
+	 * strings.
+	 */
+	if (sdev->inquiry_len < 36) {
+		printk(KERN_INFO "scsi scan: INQUIRY result too short (%d),"
+				" using 36\n", sdev->inquiry_len);
+		sdev->inquiry_len = 36;
+	}
+
+	/*
 	 * Related to the above issue:
 	 *
 	 * XXX Devices (disk or all?) should be sent a TEST UNIT READY,
