Path: csiph.com!aioe.org!news.servidellagleba.it!bofh.it!news.nic.it!robomod From: Ming Lei Newsgroups: linux.kernel Subject: Re: [PATCH v4 1/5] fs: kiocb: introduce IOCB_DONT_DIRTY_PAGE flag for direct IO Date: Sat, 06 Jun 2015 02:50:02 +0200 Message-ID: References: X-Original-To: Christoph Hellwig MIME-Version: 1.0 X-Received: by 10.202.170.82 with SMTP id t79mr188749oie.40.1433551354039; Fri, 05 Jun 2015 17:42:34 -0700 (PDT) Content-Type: text/plain; charset=UTF-8 Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 23 Organization: linux.* mail to news gateway X-Original-Cc: Linux Kernel Mailing List , Dave Kleikamp , Jens Axboe , Zach Brown , Maxim Patlasov , Andrew Morton , Alexander Viro , Tejun Heo , Dave Chinner X-Original-Date: Sat, 6 Jun 2015 08:42:33 +0800 X-Original-Message-ID: X-Original-References: <1432881338-898-1-git-send-email-ming.lei@canonical.com> <1432881338-898-2-git-send-email-ming.lei@canonical.com> <20150605150348.GA6835@infradead.org> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: aioe.org linux.kernel:1159799 On Fri, Jun 5, 2015 at 11:03 PM, Christoph Hellwig wrote: > As mentioned last time a big fat NAK for this one. We generally > do not dirty kernel pages anywhere, so a flag that must alway be set > for default behavior just to prepare for a highy hypothetical user that > in the future might want to abuse the interface is a no-go. > > Just make the dirtying behavior dependent on the iov_iter type: > dirty for ITER_IOVEC and do nothing for ITER_KVEC and ITER_BVEC. Both ITER_KVEC and ITER_BVEC doesn't mean the pages are kernel page, for example of loop and swap. That is why this patch is more flexiable, and won't cause regression since the users may have different dirtying rules as you mentioned last time. http://marc.info/?t=143093223200001&r=1&w=2 Thanks, Ming -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/