Return-Path: Date: Thu, 25 Oct 2018 17:07:29 +0200 From: David Sterba To: Sasha Levin Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Jiri Kosina Subject: Re: [PATCH AUTOSEL 4.4 08/65] btrfs: cleaner_kthread() doesn't need explicit freeze Message-ID: <20181025150729.GD16290@suse.cz> Reply-To: dsterba@suse.cz References: <20181025141705.213937-1-sashal@kernel.org> <20181025141705.213937-8-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181025141705.213937-8-sashal@kernel.org> List-ID: On Thu, Oct 25, 2018 at 10:16:08AM -0400, Sasha Levin wrote: > From: Jiri Kosina > > [ Upstream commit 838fe1887765f4cc679febea60d87d2a06bd300e ] > > cleaner_kthread() is not marked freezable, and therefore calling > try_to_freeze() in its context is a pointless no-op. > > In addition to that, as has been clearly demonstrated by 80ad623edd2d > ("Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()"), it's perfectly > valid / legal for cleaner_kthread() to stay scheduled out in an arbitrary > place during suspend (in that particular example that was waiting for > reading of extent pages), so there is no need to leave any traces of > freezer in this kthread. > > Fixes: 80ad623edd2d ("Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()") > Fixes: 696249132158 ("btrfs: clear PF_NOFREEZE in cleaner_kthread()") > Signed-off-by: Jiri Kosina > Signed-off-by: David Sterba > Signed-off-by: Sasha Levin IIRC it was some preparatory work for livepatching. I did a quick check if this is safe for 4.4 and would say yes, but the patch does not fix anything so IMO this does not need to go to stable.