[PATCH 3.12 018/235] usb: gadget: composite: correctly initialize ep->maxpacket

From: Jiri Slaby
Date: Fri Jan 27 2017 - 07:02:32 EST

From: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.


commit e8f29bb719b47a234f33b0af62974d7a9521a52c upstream.

usb_endpoint_maxp() returns wMaxPacketSize in its
raw form. Without taking into consideration that it
also contains other bits reserved for isochronous

This patch fixes one occasion where this is a
problem by making sure that we initialize
ep->maxpacket only with lower 10 bits of the value
returned by usb_endpoint_maxp(). Note that seperate
patches will be necessary to audit all call sites of
usb_endpoint_maxp() and make sure that
usb_endpoint_maxp() only returns lower 10 bits of

Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
drivers/usb/gadget/composite.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index a0b5a13b52b0..bd6400b4af89 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -125,7 +125,7 @@ int config_ep_by_speed(struct usb_gadget *g,

/* commit results */
- _ep->maxpacket = usb_endpoint_maxp(chosen_desc);
+ _ep->maxpacket = usb_endpoint_maxp(chosen_desc) & 0x7ff;
_ep->desc = chosen_desc;
_ep->comp_desc = NULL;
_ep->maxburst = 0;