diff options
| author | Krzysztof Opasiak <k.opasiak@samsung.com> | 2016-12-20 21:52:16 +0300 |
|---|---|---|
| committer | Felipe Balbi <felipe.balbi@linux.intel.com> | 2017-01-02 11:55:28 +0300 |
| commit | 7e4da3fcf7c9fe042f2f7cb7bf23861a899b4a8f (patch) | |
| tree | d29bc543131edce31c5ac39040feee02000eea3d /drivers/usb/gadget/composite.c | |
| parent | 51c1685d956221576e165dd88a20063b169bae5a (diff) | |
| download | linux-7e4da3fcf7c9fe042f2f7cb7bf23861a899b4a8f.tar.xz | |
usb: gadget: composite: Test get_alt() presence instead of set_alt()
By convention (according to doc) if function does not provide
get_alt() callback composite framework should assume that it has only
altsetting 0 and should respond with error if host tries to set
other one.
After commit dd4dff8b035f ("USB: composite: Fix bug: should test
set_alt function pointer before use it")
we started checking set_alt() callback instead of get_alt().
This check is useless as we check if set_alt() is set inside
usb_add_function() and fail if it's NULL.
Let's fix this check and move comment about why we check the get
method instead of set a little bit closer to prevent future false
fixes.
Fixes: dd4dff8b035f ("USB: composite: Fix bug: should test set_alt function pointer before use it")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Diffstat (limited to 'drivers/usb/gadget/composite.c')
| -rw-r--r-- | drivers/usb/gadget/composite.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c index 41ab61f9b6e0..002822d98fda 100644 --- a/drivers/usb/gadget/composite.c +++ b/drivers/usb/gadget/composite.c @@ -1694,9 +1694,7 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl) value = min(w_length, (u16) 1); break; - /* function drivers must handle get/set altsetting; if there's - * no get() method, we know only altsetting zero works. - */ + /* function drivers must handle get/set altsetting */ case USB_REQ_SET_INTERFACE: if (ctrl->bRequestType != USB_RECIP_INTERFACE) goto unknown; @@ -1705,7 +1703,13 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl) f = cdev->config->interface[intf]; if (!f) break; - if (w_value && !f->set_alt) + + /* + * If there's no get_alt() method, we know only altsetting zero + * works. There is no need to check if set_alt() is not NULL + * as we check this in usb_add_function(). + */ + if (w_value && !f->get_alt) break; value = f->set_alt(f, w_index, w_value); if (value == USB_GADGET_DELAYED_STATUS) { |