From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH v4 4/5] cramfs: add mmap support Date: Tue, 3 Oct 2017 08:37:00 -0700 Message-ID: <20171003153659.GA31600@infradead.org> References: <20170927233224.31676-1-nicolas.pitre@linaro.org> <20170927233224.31676-5-nicolas.pitre@linaro.org> <20171001083052.GB17116@infradead.org> <20171003145732.GA8890@infradead.org> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=t6gl+5nnj2ils1PJAHQGdW9jOjV7eXxI+cCw+WHmldk=; b=jjOy4gBSyt8dcAFMTQrI9bodr 2HTms1I0ezSG86X3QOCCUBC1Xl4h7AtdtdT2frFr1y7tP7SAwSjEaw7GQ5mrhvJHYObplFRFXU8vY CLpeXRNHOiOO1nuw11EhiVffLmiOdxTB5W1hq4W56HRC8ZrDEXxtqQHbBlDg7GbWnYEK1sCWstE8c aetVqfov05/Xgm5+xcUB+nqG2JmTLwLxAz5yxF7rHh837PyJYKXXgeFtR6a3Pd2Q7iRO31aobGXRe qj7ZFqbAQqWlq31zg6x6/gAWVnZ8IxildYY5SIN33IjYJEa1BgSoWromLX4/u7Gme/yHOFMiEjtl6 OqcMavLJQ==; Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Nicolas Pitre Cc: Christoph Hellwig , Richard Weinberger , Alexander Viro , "linux-mm@kvack.org" , linux-fsdevel , "linux-embedded@vger.kernel.org" , LKML , Chris Brandt On Tue, Oct 03, 2017 at 11:30:50AM -0400, Nicolas Pitre wrote: > Unless you have a better scheme altogether to suggest of course, given > the existing constraints. I still can't understand why this convoluted fault path that finds vma, attempts with all kinds of races and then tries to update things like vm_ops is even nessecary. We have direct mappings of physical address perfectly working in the DAX code (even with write support!) or in drivers using remap_pfn_range so a really good explanation why neither scheme can be used is needed first. -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752169AbdJCPhD (ORCPT ); Tue, 3 Oct 2017 11:37:03 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:36360 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751914AbdJCPhB (ORCPT ); Tue, 3 Oct 2017 11:37:01 -0400 Date: Tue, 3 Oct 2017 08:37:00 -0700 From: Christoph Hellwig To: Nicolas Pitre Cc: Christoph Hellwig , Richard Weinberger , Alexander Viro , "linux-mm@kvack.org" , linux-fsdevel , "linux-embedded@vger.kernel.org" , LKML , Chris Brandt Subject: Re: [PATCH v4 4/5] cramfs: add mmap support Message-ID: <20171003153659.GA31600@infradead.org> References: <20170927233224.31676-1-nicolas.pitre@linaro.org> <20170927233224.31676-5-nicolas.pitre@linaro.org> <20171001083052.GB17116@infradead.org> <20171003145732.GA8890@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.8.3 (2017-05-23) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 03, 2017 at 11:30:50AM -0400, Nicolas Pitre wrote: > Unless you have a better scheme altogether to suggest of course, given > the existing constraints. I still can't understand why this convoluted fault path that finds vma, attempts with all kinds of races and then tries to update things like vm_ops is even nessecary. We have direct mappings of physical address perfectly working in the DAX code (even with write support!) or in drivers using remap_pfn_range so a really good explanation why neither scheme can be used is needed first.