On Tue, Apr 26, 2016 at 12:57 PM, Mario Limonciello
<mario_limonciello@xxxxxxxx> wrote:
> Before this commit both code paths (hotplug and not-hotplug as determined
> by FW_OPT_UEVENT) would block on an interruptible completion, but the
> hotplugscenario also would wait until timeout and then abort. The non
> hotplugscenario (which dell-rbu followed) would block indefinitely until
> interrupted.
>
> After this commit both scenarios block on an interruptible condition but
> the hotplug scenario follows the value of firmware_loading_timeout to end.
> This changed the situation for the non hotplug scenario to instead wait
> for MAX_JIFFY_OFFSET. This should have the same result, but dell-rbu was
> failing with negative values returned from
> wait_for_completion_interruptible_timeout after completion occurred.
>
> This shouldn't be possible, but it was happening because the return is a
> long but the value it was being saved to was an int. When completion
> occurs quickly wait_for_completion_interruptible_timeout returns how much
> time was left (which happens to be a very big number since the timeout was
> MAX_JIFFY_OFFSET) One test run of mine returned 4611686018427368747.
>
> Other parts of the kernel with this type of return don't have problems
> because they use smaller timeouts.
>
> So to fix this: change the test to not store the value to an int, but
> rather directly compare against what
> wait_for_completion_interruptible_timeout can return.
>
> Fixes: 68ff2a00dbf59 (firmware_loader: handle timeout via wait_for_completion_interruptible_timeout())
> CC: stable@xxxxxxxxxxxxxxx
> CC: stuart_hayes@xxxxxxxx
> Signed-off-by: Mario Limonciello <mario_limonciello@xxxxxxxx>
> ---
> drivers/base/firmware_class.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
> index 773fc30..223af70 100644
> --- a/drivers/base/firmware_class.c
> +++ b/drivers/base/firmware_class.c
> @@ -917,14 +917,11 @@ static int _request_firmware_load(struct firmware_priv *fw_priv,
> timeout = MAX_JIFFY_OFFSET;
> }
>
> - retval = wait_for_completion_interruptible_timeout(&buf->completion,
> - timeout);
> - if (retval == -ERESTARTSYS || !retval) {
> + if (wait_for_completion_interruptible_timeout(&buf->completion,
> + timeout) <= 0) {
> mutex_lock(&fw_lock);
> fw_load_abort(fw_priv);
> mutex_unlock(&fw_lock);
> - } else if (retval > 0) {
> - retval = 0;
> }
Good catch, thanks!
Acked-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>
>
> if (is_fw_load_aborted(buf))
> --
> 2.7.4
>
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