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| author | Alan Stern <stern@rowland.harvard.edu> | 2018-03-27 17:27:06 +0300 |
|---|---|---|
| committer | Felipe Balbi <felipe.balbi@linux.intel.com> | 2018-04-23 14:07:36 +0300 |
| commit | 5d1332a8eabd8bd5b8c322d45542968ee6f113be (patch) | |
| tree | dc27ad27ef366abe6b355bd65a1ee5b131537106 | |
| parent | 6d08b06e67cd117f6992c46611dfb4ce267cd71e (diff) | |
| download | linux-5d1332a8eabd8bd5b8c322d45542968ee6f113be.tar.xz | |
usb: gadget: udc: core: Document the relation between usb_ep_queue() and completion callback
Improve the kerneldoc for usb_ep_queue() to note explicitly that the
request's completion routine will be called if and only if the return
value is 0. The corresponding fact about usb_submit_urb() for the
host-side API has long been documented, and this has always been the
intention for the gadget API. But until now, documentation seems to
have been lacking.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
| -rw-r--r-- | drivers/usb/gadget/udc/core.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c index 842814bc0e4f..cab5e4f09924 100644 --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -244,6 +244,12 @@ EXPORT_SYMBOL_GPL(usb_ep_free_request); * 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. + * + * If and only if @req is successfully queued (the return value is zero), + * @req->complete() will be called exactly once, when the Gadget core and + * UDC are finished with the request. When the completion function is called, + * control of the request is returned to the device driver which submitted it. + * The completion handler may then immediately free or reuse @req. */ int usb_ep_queue(struct usb_ep *ep, struct usb_request *req, gfp_t gfp_flags) |