linux-kernel - Re: [PATCH] test_firmware: fix setting old custom fw path back on exit, second try

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Date:   Tue, 3 Apr 2018 12:54:46 -0700
From:   "Luis R. Rodriguez" <mcgrof@...nel.org>
To:     Ben Hutchings <ben.hutchings@...ethink.co.uk>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Shuah Khan <shuah@...nel.org>, linux-kselftest@...r.kernel.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] test_firmware: fix setting old custom fw path back on
 exit, second try

On Tue, Apr 3, 2018 at 12:48 PM, Ben Hutchings
<ben.hutchings@...ethink.co.uk> wrote:
> Commit 65c79230576 tried to clear the custom firmware path on exit by
> writing a single space to the firmware_class.path parameter.  This
> doesn't work because nothing strips this space from the value stored
> and fw_get_filesystem_firmware() only ignores zero-length paths.
>
> Instead, write a null byte.
>
> Fixes: 0a8adf58475 ("test: add firmware_class loader test")
> Fixes: 65c79230576 ("test_firmware: fix setting old custom fw path back on exit")
> Signed-off-by: Ben Hutchings <ben.hutchings@...ethink.co.uk>

Thanks for the patch! Also can you re-send and address Greg and
linux-kernel ? There's significant changes to the firmware API on its
way to Linus to I think if we want to merge this it should go through
Greg at this point as he also merged some new changes I made to these
scripts.

> ---
>  tools/testing/selftests/firmware/fw_filesystem.sh | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/firmware/fw_filesystem.sh b/tools/testing/selftests/firmware/fw_filesystem.sh
> index f9508e1a4058..6b63b6bf2661 100755
> --- a/tools/testing/selftests/firmware/fw_filesystem.sh
> +++ b/tools/testing/selftests/firmware/fw_filesystem.sh
> @@ -46,9 +46,11 @@ test_finish()
>                 echo "$OLD_TIMEOUT" >/sys/class/firmware/timeout
>         fi
>         if [ "$OLD_FWPATH" = "" ]; then
> -               OLD_FWPATH=" "
> +               # A zero-length write won't work; write a null byte
> +               printf '\000' >/sys/module/firmware_class/parameters/path
> +       else
> +               echo -n "$OLD_FWPATH" >/sys/module/firmware_class/parameters/path

Odd I am pretty sure I tested this and it worked for me. Wonder what
it could have been... What shell are you using? I used bash.

  Luis

>         fi
> -       echo -n "$OLD_FWPATH" >/sys/module/firmware_class/parameters/path
>         rm -f "$FW"
>         rmdir "$FWPATH"
>  }
> --
> 2.16.2
>