Limit USB storage transfers to 240 sectors.

drivers/usb/storage/scsiglue.c

@@ -312,6 +312,9 @@ struct scsi_host_template usb_stor_host_template = {
 	/* lots of sg segments can be handled */
 	.sg_tablesize =			SG_ALL,
 
+	/* limit the total size of a transfer to 120 KB */
+	.max_sectors =                  240,
+
 	/* merge commands... this seems to help performance, but
 	 * periodically someone should test to see which setting is more
 	 * optimal.