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

[Kamal Mostafa]

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-3.8.y-queue branch of the 3.8.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-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.3.

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

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 11ed28a7164959c81a282b3c96460e20130dad7d 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: 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>
[ kamal: backport to 3.8 ]
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/dwc3/gadget.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 09835b6..3c0351a 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1627,10 +1627,20 @@ 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