[PATCH 4.14 017/164] usb: gadget: udc: core: update usb_ep_queue() documentation

From: Greg Kroah-Hartman
Date: Sun Apr 22 2018 - 11:39:05 EST

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


From: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>

commit eaa358c7790338d83bb6a31258bdc077de120414 upstream.

Mention that ->complete() should never be called from within

Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/usb/gadget/udc/core.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -249,6 +249,9 @@ EXPORT_SYMBOL_GPL(usb_ep_free_request);
* arranges to poll once per interval, and the gadget driver usually will
* have queued some data to transfer at that time.
+ * Note that @req's ->complete() callback must never be called from
+ * within usb_ep_queue() as that can create deadlock situations.
+ *
* Returns zero, or a negative error code. Endpoints that are not enabled
* report errors; errors will also be
* reported when the usb peripheral is disconnected.