From a7c12eaf2e5eea0c15242ebb7d1d3b6e7fcb62bb Mon Sep 17 00:00:00 2001 From: Felipe Balbi Date: Thu, 18 Sep 2014 10:01:55 -0500 Subject: [PATCH] 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 f2267089ea17fa97b796b1b4247e3f8957655df3 (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 --- drivers/usb/gadget/composite.c | 51 ++++++++++++++++++++++++++++++++-- 1 file changed, 48 insertions(+), 3 deletions(-) diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c index 09602dc90205..e071d580346e 100644 --- a/drivers/usb/gadget/composite.c +++ b/drivers/usb/gadget/composite.c @@ -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; -- 2.20.1