From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from foss.arm.com ([217.140.101.70]:43896 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725834AbeIBMCc (ORCPT ); Sun, 2 Sep 2018 08:02:32 -0400 Date: Sun, 02 Sep 2018 08:47:29 +0100 Message-ID: <86y3ckwdbi.wl-marc.zyngier@arm.com> From: Marc Zyngier To: Sasha Levin Cc: "stable@vger.kernel.org" , Olof Johansson Subject: Re: [PATCH AUTOSEL 4.18 008/113] iommu/rockchip: Handle errors returned from PM framework In-Reply-To: <20180830180050.35735-8-alexander.levin@microsoft.com> References: <20180830180050.35735-1-alexander.levin@microsoft.com> <20180830180050.35735-8-alexander.levin@microsoft.com> MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII Sender: stable-owner@vger.kernel.org List-ID: On Thu, 30 Aug 2018 19:01:16 +0100, Sasha Levin wrote: > > From: Marc Zyngier > > [ Upstream commit 3fc7c5c0cff3150e471f5fd12f59971c6d2c6513 ] > > pm_runtime_get_if_in_use can fail: either PM has been disabled > altogether (-EINVAL), or the device hasn't been enabled yet (0). > Sadly, the Rockchip IOMMU driver tends to conflate the two things > by considering a non-zero return value as successful. > > This has the consequence of hiding other bugs, so let's handle this > case throughout the driver, with a WARN_ON_ONCE so that we can try > and work out what happened. > > Fixes: 0f181d3cf7d98 ("iommu/rockchip: Add runtime PM support") > Reviewed-by: Heiko Stuebner > Signed-off-by: Marc Zyngier > Signed-off-by: Olof Johansson > Signed-off-by: Sasha Levin Picking this patch on its own feels like a bad idea if CONFIG_PM is not selected. Consider picking up 7db7a8f5638a and d1558dfd9f22 which guarantee that things won't break. Thanks, M. -- Jazz is not dead, it just smell funny.