A request allocated from e.g. ep1out cannot
be queued to any other endpoint. This bug has
been in f_loopback at least since mid-2011 and
since nobody has really screamed about it, we're
not backporting to any stable kernels.
Debugged with MUSB since that's the only controller
which complains about this case.
Signed-off-by: Felipe Balbi <balbi@xxxxxx>
---
drivers/usb/gadget/function/f_loopback.c | 87 +++++++++++++++-----------------
1 file changed, 42 insertions(+), 45 deletions(-)
diff --git a/drivers/usb/gadget/function/f_loopback.c b/drivers/usb/gadget/function/f_loopback.c
index bf04389..298b461 100644
--- a/drivers/usb/gadget/function/f_loopback.c
+++ b/drivers/usb/gadget/function/f_loopback.c
@@ -253,22 +253,13 @@ static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
case 0: /* normal completion? */
if (ep == loop->out_ep) {
- /* loop this OUT packet back IN to the host */
req->zero = (req->actual < req->length);
req->length = req->actual;
- status = usb_ep_queue(loop->in_ep, req, GFP_ATOMIC);
- if (status == 0)
- return;
-
- /* "should never get here" */
- ERROR(cdev, "can't loop %s to %s: %d\n",
- ep->name, loop->in_ep->name,
- status);
}
/* queue the buffer for some later OUT packet */
req->length = buflen;
- status = usb_ep_queue(loop->out_ep, req, GFP_ATOMIC);
+ status = usb_ep_queue(ep, req, GFP_ATOMIC);
if (status == 0)
return;
@@ -308,60 +299,66 @@ static inline struct usb_request *lb_alloc_ep_req(struct usb_ep *ep, int len)
return alloc_ep_req(ep, len, buflen);
}
-static int
-enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
+static int enable_endpoint(struct usb_composite_dev *cdev, struct f_loopback *loop,
+ struct usb_ep *ep)
{
- int result = 0;
- struct usb_ep *ep;
struct usb_request *req;
unsigned i;
+ int result;
- /* one endpoint writes data back IN to the host */
- ep = loop->in_ep;
+ /*
+ * one endpoint writes data back IN to the host while another endpoint
+ * just reads OUT packets
+ */
result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
if (result)
- return result;
+ goto fail0;
result = usb_ep_enable(ep);
if (result < 0)
- return result;
- ep->driver_data = loop;
-
- /* one endpoint just reads OUT packets */
- ep = loop->out_ep;
- result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
- if (result)
goto fail0;
-
- result = usb_ep_enable(ep);
- if (result < 0) {
-fail0:
- ep = loop->in_ep;
- usb_ep_disable(ep);
- ep->driver_data = NULL;
- return result;
- }
ep->driver_data = loop;
- /* allocate a bunch of read buffers and queue them all at once.
+ /*
+ * allocate a bunch of read buffers and queue them all at once.
* we buffer at most 'qlen' transfers; fewer if any need more
* than 'buflen' bytes each.
*/
for (i = 0; i < qlen && result == 0; i++) {
req = lb_alloc_ep_req(ep, 0);
- if (req) {
- req->complete = loopback_complete;
- result = usb_ep_queue(ep, req, GFP_ATOMIC);
- if (result)
- ERROR(cdev, "%s queue req --> %d\n",
- ep->name, result);
- } else {
- usb_ep_disable(ep);
- ep->driver_data = NULL;
- result = -ENOMEM;
- goto fail0;
+ if (!req)
+ goto fail1;
+
+ req->complete = loopback_complete;
+ result = usb_ep_queue(ep, req, GFP_ATOMIC);
+ if (result) {
+ ERROR(cdev, "%s queue req --> %d\n",
+ ep->name, result);
+ goto fail1;
}
}
+ return 0;
+
+fail1:
+ usb_ep_disable(ep);
+
+fail0:
+ return result;
+}
+
+static int
+enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
+{
+ int result = 0;
+
+ result = enable_endpoint(cdev, loop, loop->in_ep);
+ if (result)
+ return result;
+
+ result = enable_endpoint(cdev, loop, loop->out_ep);
+ if (result)
+ return result;
+
DBG(cdev, "%s enabled\n", loop->function.name);
return result;
}
--
2.1.0.GIT
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