Commits
![Ian Abbott](https://secure.gravatar.com/avatar/f3fb4783c5305162d323ea68b3de634c.jpg?s=96&d=mm)
Ian Abbott committed 322146d5d48
staging: comedi: don't poll_wait on same subdevice twice Comedi subdevices that support asynchronous acquisition commands have a wait queue head used for blocking reads or writes and for the poll file operation. The comedi device may have several subdevices that support "read" and/or "write" commands, but each open file object has at most one "read" subdevice and one "write" subdevice. It's possible (though rare) for those to be the same subdevice if the subdevice supports commands in either direction. In that case, the "poll" file operation doesn't really need to do a `poll_wait()` on the same subdevice twice. Although harmless, it wastes a poll table entry. Check for that, and avoid it. Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>