USB: usb-storage: increase max_sectors for tape drives

This patch (as1203) increases the max_sector limit for USB tape
drives. By default usb-storage sets max_sectors to 240 (i.e., 120 KB)
for all devices. But tape drives need a higher limit, since tapes can
and do have very large block sizes. Without the ability to transfer
an entire large block in a single command, such tapes can't be used.

This fixes Bugzilla #12207.

Signed-off-by: Alan Stern <[e-mail]>
Reported-and-tested-by: Phil Mitchell <[e-mail]>
Cc: stable <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/storage/scsiglue.c

···
 		if (sdev->request_queue->max_sectors > max_sectors)
 			blk_queue_max_sectors(sdev->request_queue,
 					      max_sectors);
+	} else if (sdev->type == TYPE_TAPE) {
+		/* Tapes need much higher max_sector limits, so just
+		 * raise it to the maximum possible (4 GB / 512) and
+		 * let the queue segment size sort out the real limit.
+		 */
+		blk_queue_max_sectors(sdev->request_queue, 0x7FFFFF);
 	}
 
 	/* Some USB host controllers can't do DMA; they have to use PIO.