Re: [PATCH v2 4/5] firmware: actually return NULL on failed request_firmware_nowait()

On Wed, Dec 09, 2015 at 02:50:28PM -0800, Brian Norris wrote:

The kerneldoc for request_firmware_nowait() says that it may call the
provided cont() callback with @fw == NULL, if the firmware request
fails. However, this is not the case when called with an empty string
(""). This case is short-circuited by the 'name[0] == '\0'' check
introduced in commit 471b095dfe0d ("firmware_class: make sure fw requests
contain a name"), so _request_firmware() never gets to set the fw to
NULL.

Noticed while using the new 'trigger_async_request' testing hook:

<-- snip -->

    # printf '\x00' > /sys/devices/virtual/misc/test_firmware/trigger_async_request
    [   32.126322] test_firmware: loading ''
    [   32.129995] test_firmware: failed to async load firmware
    -bash: printf: write error: No such device

Fixes: 471b095dfe0d ("firmware_class: make sure fw requests contain a name")
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Ming Lei <redacted>
Acked-by: Kees Cook <redacted>

Acked-by: Luis R. Rodriguez <redacted>

  Luis