From mboxrd@z Thu Jan 1 00:00:00 1970 From: josh@joshtriplett.org Subject: Re: [PATCH 1/1] jffs2: fix sparse warning: unexpected unlock Date: Fri, 26 Sep 2014 16:17:27 -0700 Message-ID: <20140926231727.GD20917@cloud> References: <1411065976-20386-1-git-send-email-fabf@skynet.be> <20140922181250.GN1193@ld-irv-0074> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from relay3-d.mail.gandi.net ([217.70.183.195]:50632 "EHLO relay3-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754819AbaIZXRd (ORCPT ); Fri, 26 Sep 2014 19:17:33 -0400 Content-Disposition: inline In-Reply-To: <20140922181250.GN1193@ld-irv-0074> Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: Brian Norris Cc: Fabian Frederick , linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, David Woodhouse , linux-sparse@vger.kernel.org On Mon, Sep 22, 2014 at 11:12:50AM -0700, Brian Norris wrote: > + linux-sparse > > On Thu, Sep 18, 2014 at 08:46:16PM +0200, Fabian Frederick wrote: > > fs/jffs2/summary.c:846:5: warning: context imbalance in 'jffs2_sum_write_sumnode' - unexpected unlock > > > > Signed-off-by: Fabian Frederick > > --- > > fs/jffs2/summary.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/fs/jffs2/summary.c b/fs/jffs2/summary.c > > index c522d09..a0bac7b 100644 > > --- a/fs/jffs2/summary.c > > +++ b/fs/jffs2/summary.c > > @@ -844,6 +844,8 @@ static int jffs2_sum_write_data(struct jffs2_sb_info *c, struct jffs2_eraseblock > > /* Write out summary information - called from jffs2_do_reserve_space */ > > > > int jffs2_sum_write_sumnode(struct jffs2_sb_info *c) > > + __releases(&c->erase_completion_lock) > > + __acquires(&c->erase_completion_lock) > > I'm not too familiar with sparse notations, but Documentation/sparse.txt > suggests the above is wrong, and the following is more accurate: > > __must_hold(&c->erase_completion_lock) > > But it looks like there are several other examples which do this. > Anyway, here's the relevant doc text, in case someone wants to clarify > it for me, or else tell me the documentation is wrong: > > __must_hold - The specified lock is held on function entry and exit. > > __acquires - The specified lock is held on function exit, but not entry. > > __releases - The specified lock is held on function entry, but not exit. > > So __acquires and __releases look mutually exclusive, but it's not clear > if __must_hold will actually cover what we want. (I haven't tested it.) __must_hold is indeed the correct annotation. (There isn't currently anything enforcing that, though.) - Josh Triplett