[ 3.5.y.z extended stable ] Patch "usb: dwc3: gadget: free trb pool only from epnum 2" has been added to staging queue

[Luis Henriques]

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

    usb: dwc3: gadget: free trb pool only from epnum 2

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

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

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From ddbd2c3a14505e56b33217a672d510c37f2f7433 Mon Sep 17 00:00:00 2001
From: George Cherian <george.cherian at ti.com>
Date: Mon, 27 May 2013 14:35:49 +0530
Subject: [PATCH] usb: dwc3: gadget: free trb pool only from epnum 2

commit 5bf8fae33d14cc5c3c53a926f9079f92c8b082b0 upstream.

we never allocate a TRB pool for physical endpoints
0 and 1 so trying to free it (a invalid TRB pool pointer)
will lead us in a warning while removing dwc3.ko module.

In order to fix the situation, all we have to do is skip
dwc3_free_trb_pool() for physical endpoints 0 and 1 just
as we while deleting endpoints from the endpoints list.

Signed-off-by: George Cherian <george.cherian at ti.com>
Signed-off-by: Felipe Balbi <balbi at ti.com>
[ luis: backport to 3.5: adjust context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/usb/dwc3/gadget.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index fae7885..3530c2b 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1537,10 +1537,19 @@ static void dwc3_gadget_free_endpoints(struct dwc3 *dwc)

 	for (epnum = 0; epnum < DWC3_ENDPOINTS_NUM; epnum++) {
 		dep = dwc->eps[epnum];
-		dwc3_free_trb_pool(dep);
-
-		if (epnum != 0 && epnum != 1)
+		/*
+		 * Physical endpoints 0 and 1 are special; they form the
+		 * bi-directional USB endpoint 0.
+		 *
+		 * For those two physical endpoints, we don't allocate a TRB
+		 * pool nor do we add them the endpoints list. Due to that, we
+		 * shouldn't do these two operations otherwise we would end up
+		 * with all sorts of bugs when removing dwc3.ko.
+		 */
+		if (epnum != 0 && epnum != 1) {
+			dwc3_free_trb_pool(dep);
 			list_del(&dep->endpoint.ep_list);
+		}

 		kfree(dep);
 	}
--
1.8.1.2