[3.19.y-ckt stable] Patch "USB: uas: Reduce can_queue to MAX_CMNDS" has been added to the 3.19.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    USB: uas: Reduce can_queue to MAX_CMNDS

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt18.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 34753b41d47e545f97dac8e2e64a9fe09541840f Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede at redhat.com>
Date: Mon, 7 Mar 2016 20:11:52 +0100
Subject: USB: uas: Reduce can_queue to MAX_CMNDS

commit 55ff8cfbc4e12a7d2187df523938cc671fbebdd1 upstream.

The uas driver can never queue more then MAX_CMNDS (- 1) tags and tags
are shared between luns, so there is no need to claim that we can_queue
some random large number.

Not claiming that we can_queue 65536 commands, fixes the uas driver
failing to initialize while allocating the tag map with a "Page allocation
failure (order 7)" error on systems which have been running for a while
and thus have fragmented memory.

Reported-and-tested-by: Yves-Alexis Perez <corsac at corsac.net>
Signed-off-by: Hans de Goede <hdegoede at redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/storage/uas.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index 75e4979..637ee77 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -812,7 +812,7 @@ static struct scsi_host_template uas_host_template = {
 	.slave_configure = uas_slave_configure,
 	.eh_abort_handler = uas_eh_abort_handler,
 	.eh_bus_reset_handler = uas_eh_bus_reset_handler,
-	.can_queue = 65536,	/* Is there a limit on the _host_ ? */
+	.can_queue = MAX_CMNDS,
 	.this_id = -1,
 	.sg_tablesize = SG_NONE,
 	.cmd_per_lun = 1,	/* until we override it */
--
2.7.4