usb: gadget: uvc: configfs: Prevent format changes after linking header

Quoted 5 lines · Laurent Pinchart

From: Joel Pepper <[email protected]>

While checks are in place to avoid attributes and children of a format being manipulated after the format is linked into the streaming header, the linked flag was never actually set, invalidating the protections.

That explains what's wrong, but not what we do about it. How about adding:

"Update the flag as appropriate in the header link calls."

Quoted 1 line

Signed-off-by Joel Pepper <[email protected]>

Missing and S-o-B from Laurent here? (I guess that will be added later?)

Otherwise,

Reviewed-by Kieran Bingham <[email protected]>

Quoted 33 lines

---

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

(quoted diff) +0 -0

b/drivers/usb/gadget/function/uvc_configfs.c index b8763343dcae..799dc32c5bc7 100644

drivers/usb/gadget/function/uvc_configfs.c +0 -0

@@ -928,6 +928,7 @@ static int uvcg_streaming_header_allow_link(struct

config_item *src,>

drivers/usb/gadget/function/uvc_configfs.c +1 -0

 	format_ptr->fmt = target_fmt;
 	list_add_tail(&format_ptr->entry, &src_hdr->formats);
 	++src_hdr->num_fmt;
 
+	++target_fmt->linked;
 
 out:
 	mutex_unlock(&opts->lock);

@@ -965,6 +966,8 @@ static void uvcg_streaming_header_drop_link(struct

config_item *src,>

drivers/usb/gadget/function/uvc_configfs.c +2 -0

 			break;
 
 		}
 
+	--target_fmt->linked;
+
 
 out:
 	mutex_unlock(&opts->lock);
 	mutex_unlock(su_mutex);