Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752570AbcDZLZM (ORCPT ); Tue, 26 Apr 2016 07:25:12 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:52399 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751815AbcDZLZK (ORCPT ); Tue, 26 Apr 2016 07:25:10 -0400 MIME-Version: 1.0 In-Reply-To: <1461646652-20393-1-git-send-email-mario_limonciello@dell.com> References: <1461646652-20393-1-git-send-email-mario_limonciello@dell.com> Date: Tue, 26 Apr 2016 19:25:07 +0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 1/1] firmware: correct test of wait_for_completion_interruptible_timeout return From: Ming Lei To: Mario Limonciello Cc: LKML , stable , stuart_hayes@dell.com Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2771 Lines: 65 On Tue, Apr 26, 2016 at 12:57 PM, Mario Limonciello 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@vger.kernel.org > CC: stuart_hayes@dell.com > Signed-off-by: Mario Limonciello > --- > 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 > > if (is_fw_load_aborted(buf)) > -- > 2.7.4 >