This is a note to let you know that I've just added the patch titled
usb: gadget: composite: Test get_alt() presence instead of set_alt()
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-gadget-composite-test-get_alt-presence-instead-of-set_alt.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7e4da3fcf7c9fe042f2f7cb7bf23861a899b4a8f Mon Sep 17 00:00:00 2001
From: Krzysztof Opasiak <k.opasiak@xxxxxxxxxxx>
Date: Tue, 20 Dec 2016 19:52:16 +0100
Subject: usb: gadget: composite: Test get_alt() presence instead of set_alt()
From: Krzysztof Opasiak <k.opasiak@xxxxxxxxxxx>
commit 7e4da3fcf7c9fe042f2f7cb7bf23861a899b4a8f upstream.
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")
Signed-off-by: Krzysztof Opasiak <k.opasiak@xxxxxxxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/gadget/composite.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1601,9 +1601,7 @@ composite_setup(struct usb_gadget *gadge
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;
@@ -1612,7 +1610,13 @@ composite_setup(struct usb_gadget *gadge
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) {
Patches currently in stable-queue which might be from k.opasiak@xxxxxxxxxxx are
queue-4.4/usb-gadget-composite-test-get_alt-presence-instead-of-set_alt.patch
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