[patch 11/88] USB: usb-storage: increase max_sectors for tape drives

Greg KH
2009-04-30T17:11:59Z

[-- Attachment #1: 0010-USB-usb-storage-increase-max_sectors-for-tape-driv.patch --]
[-- Type: text/plain, Size: 1523 bytes --]

2.6.28-stable review patch. If anyone has any objections, please let us know.

------------------

From: Alan Stern <stern@rowland.harvard.edu>
'
upstream commit: 5c16034d73da2c1b663aa25dedadbc533b3d811c

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 <stern@rowland.harvard.edu>
Reported-and-tested-by: Phil Mitchell <philipm@sybase.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---
drivers/usb/storage/scsiglue.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -135,6 +135,12 @@ static int slave_configure(struct scsi_d
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);
}

/* We can't put these settings in slave_alloc() because that gets