From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id 109BA6B0055 for ; Tue, 17 Mar 2009 01:42:37 -0400 (EDT) From: Nick Piggin Subject: Re: [aarcange@redhat.com: [PATCH] fork vs gup(-fast) fix] Date: Tue, 17 Mar 2009 16:42:24 +1100 References: <1237007189.25062.91.camel@pasglop> <200903170529.08995.nickpiggin@yahoo.com.au> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200903171642.25760.nickpiggin@yahoo.com.au> Sender: owner-linux-mm@kvack.org To: Linus Torvalds Cc: KOSAKI Motohiro , Benjamin Herrenschmidt , Andrea Arcangeli , Ingo Molnar , Nick Piggin , Hugh Dickins , KAMEZAWA Hiroyuki , linux-mm@kvack.org List-ID: On Tuesday 17 March 2009 06:17:21 Linus Torvalds wrote: > On Tue, 17 Mar 2009, Nick Piggin wrote: > > What's buggy about it? Stupid bugs, or fundamentally broken? > > The lack of locking. I don't think it's broken. I can't see a problem. > > In my opinion it is not, given that you have to convert callers. If you > > say that you only care about fixing O_DIRECT, then yes I would probably > > agree the lock is nicer in that case. > > F*ck me, I'm not going to bother to argue. I'm not going to merge your > patch, it's that easy. > > Quite frankly, I don't think that the "bug" is a bug to begin with. > O_DIRECT+fork() can damn well continue to be broken. But if we fix it, we > fix it the _clean_ way with a simple patch, not with that shit-for-logic > horrible decow crap. > > It's that simple. I refuse to take putrid industrial waste patches for > something like this. I consider it is clean because it only adds branches in 3 places that are not taken unless direct IO and fork are used, and it fixes the "problem" in the VM directly leaving get_user_pages unchanged. I don't think it is conceptually such a problem to copy pages rather than COW them in fork. Seems fairly straightforward to me. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org