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usb: gadget: composite: conditionally dequeue os_desc and setup requests 

In case we unload a gadget driver while any of
os_desc_req or req are still pending, we need
to make sure to dequeue them.

By using our setup_pending and os_desc_pending
flags we achieve that in a way that doesn't
cause any regressions because we won't dequeue
a request which was already completed.

The original idea came from Li Jun's commit
f2267089ea
(usb: gadget: composite: dequeue cdev->req
before free it in composite_dev_cleanup) which,
unfortunately, caused two regressions (kfree()
being called before usb_ep_dequeue() and calling
usb_ep_dequeue() when the request was already
completed). That commit also didn't take care
of os_desc_req which can fall into the same
situation so we must care for that one too.

Note that in order to make code slightly easier
to read, we introduce composite_ep_queue() which
hides details about how to fiddle with our pending
flags.

Signed-off-by: Felipe Balbi <balbi@ti.com>
This commit is contained in:
Felipe Balbi 2014-09-18 10:01:55 -05:00
parent 57943716ff
commit a7c12eaf2e
1 changed files with 48 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

51
drivers/usb/gadget/composite.c
View File

@ -1246,10 +1246,49 @@ EXPORT_SYMBOL_GPL(usb_string_ids_n);
static void composite_setup_complete(struct usb_ep *ep, struct usb_request *req)
{
struct usb_composite_dev *cdev;
if (req->status || req->actual != req->length)
DBG((struct usb_composite_dev *) ep->driver_data,
"setup complete --> %d, %d/%d\n",
req->status, req->actual, req->length);
/*
* REVIST The same ep0 requests are shared with function drivers
* so they don't have to maintain the same ->complete() stubs.
*
* Because of that, we need to check for the validity of ->context
* here, even though we know we've set it to something useful.
*/
if (!req->context)
return;
cdev = req->context;
if (cdev->req == req)
cdev->setup_pending = false;
else if (cdev->os_desc_req == req)
cdev->os_desc_pending = false;
else
WARN(1, "unknown request %p\n", req);
}
static int composite_ep0_queue(struct usb_composite_dev *cdev,
struct usb_request *req, gfp_t gfp_flags)
{
int ret;
ret = usb_ep_queue(cdev->gadget->ep0, req, gfp_flags);
if (ret == 0) {
if (cdev->req == req)
cdev->setup_pending = true;
else if (cdev->os_desc_req == req)
cdev->os_desc_pending = true;
else
WARN(1, "unknown request %p\n", req);
}
return ret;
}
static int count_ext_compat(struct usb_configuration *c)
@ -1690,7 +1729,7 @@ unknown:
req->length = value;
req->context = cdev;
req->zero = value < w_length;
value = usb_ep_queue(gadget->ep0, req, GFP_ATOMIC);
value = composite_ep0_queue(cdev, req, GFP_ATOMIC);
if (value < 0) {
DBG(cdev, "ep_queue --> %d\n", value);
req->status = 0;
@ -1762,7 +1801,7 @@ unknown:
req->length = value;
req->context = cdev;
req->zero = value < w_length;
value = usb_ep_queue(gadget->ep0, req, GFP_ATOMIC);
value = composite_ep0_queue(cdev, req, GFP_ATOMIC);
if (value < 0) {
DBG(cdev, "ep_queue --> %d\n", value);
req->status = 0;
@ -1957,10 +1996,16 @@ void composite_dev_cleanup(struct usb_composite_dev *cdev)
kfree(uc);
}
if (cdev->os_desc_req) {
if (cdev->os_desc_pending)
usb_ep_dequeue(cdev->gadget->ep0, cdev->os_desc_req);
kfree(cdev->os_desc_req->buf);
usb_ep_free_request(cdev->gadget->ep0, cdev->os_desc_req);
}
if (cdev->req) {
if (cdev->setup_pending)
usb_ep_dequeue(cdev->gadget->ep0, cdev->req);
kfree(cdev->req->buf);
usb_ep_free_request(cdev->gadget->ep0, cdev->req);
}
@ -2165,7 +2210,7 @@ void usb_composite_setup_continue(struct usb_composite_dev *cdev)
DBG(cdev, "%s: Completing delayed status\n", __func__);
req->length = 0;
req->context = cdev;
value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
value = composite_ep0_queue(cdev, req, GFP_ATOMIC);
if (value < 0) {
DBG(cdev, "ep_queue --> %d\n", value);
req->status = 0;