From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f199.google.com (mail-io0-f199.google.com [209.85.223.199]) by kanga.kvack.org (Postfix) with ESMTP id 953486B0038 for ; Mon, 2 Oct 2017 19:33:32 -0400 (EDT) Received: by mail-io0-f199.google.com with SMTP id q7so5032887ioi.12 for ; Mon, 02 Oct 2017 16:33:32 -0700 (PDT) Received: from mail-sor-f41.google.com (mail-sor-f41.google.com. [209.85.220.41]) by mx.google.com with SMTPS id b3sor8894298qkd.1.2017.10.02.16.33.31 for (Google Transport Security); Mon, 02 Oct 2017 16:33:31 -0700 (PDT) Date: Mon, 2 Oct 2017 19:33:29 -0400 (EDT) From: Nicolas Pitre Subject: Re: [PATCH v4 4/5] cramfs: add mmap support In-Reply-To: Message-ID: References: <20170927233224.31676-1-nicolas.pitre@linaro.org> <20170927233224.31676-5-nicolas.pitre@linaro.org> <20171001083052.GB17116@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Richard Weinberger Cc: Christoph Hellwig , Alexander Viro , "linux-mm@kvack.org" , linux-fsdevel , "linux-embedded@vger.kernel.org" , LKML , Chris Brandt On Tue, 3 Oct 2017, Richard Weinberger wrote: > On Mon, Oct 2, 2017 at 12:29 AM, Nicolas Pitre wrote: > > On Sun, 1 Oct 2017, Christoph Hellwig wrote: > > > >> up_read(&mm->mmap_sem) in the fault path is a still a complete > >> no-go, > >> > >> NAK > > > > Care to elaborate? > > > > What about mm/filemap.c:__lock_page_or_retry() then? > > As soon you up_read() in the page fault path other tasks will race > with you before > you're able to grab the write lock. But I _know_ that. Could you highlight an area in my code where this is not accounted for? Nicolas -- 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