From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: What does this sparse warning mean in posix_acl.h? Date: Sat, 17 Aug 2013 17:23:26 -0400 Message-ID: <20130817212326.GI30769@thunk.org> References: <20130817205554.GH30769@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from imap.thunk.org ([74.207.234.97]:45140 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754609Ab3HQVXb (ORCPT ); Sat, 17 Aug 2013 17:23:31 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: Linus Torvalds Cc: linux-fsdevel , Sparse Mailing-list On Sat, Aug 17, 2013 at 02:14:45PM -0700, Linus Torvalds wrote: > > So anybody using "get_cached_acl()" is safe. It gets either a locked > ref-counted ACL pointer, or an unlocked optimistic NULL pointer. Ah, I see. But as we start adding the RCU annotations and the calls to rcu_derference(), then I imagine we'll start triggering warnings from various other static analysis tools, even if it makes sparse happy. > So the ACL accesses are this somewhat strange mix of RCU and non-RCU > use. We probably could make *more* of them use the RCU model, but > apart from the RCU pathname lookup nothing else has ever been critical > enough to care. Ugh. OK, I care mostly because it's adding noise to my make C=1 runs, but I'm not sure I care enough to fix it up right away. I'll put it on my todo list, and hope someone beats me to it. :-) - Ted