From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Date: Thu, 13 Aug 2015 14:35:28 +0000 Subject: Re: RFC: prepare for struct scatterlist entries without page backing Message-Id: <20150813143528.GC17183@lst.de> List-Id: References: <1439363150-8661-1-git-send-email-hch@lst.de> <55CB3F47.3000902@plexistor.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Julian Calaby Cc: Boaz Harrosh , Christoph Hellwig , Linus Torvalds , axboe@kernel.dk, linux-mips@linux-mips.org, linux-ia64@vger.kernel.org, linux-nvdimm@ml01.01.org, David Howells , sparclinux , Hans-Christian Egtvedt , linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, x86@kernel.org, David Woodhouse , =?iso-8859-1?Q?H=E5vard?= Skinnemoen , linux-xtensa@linux-xtensa.org, grundler@parisc-linux.org, realmz6@gmail.com, alex.williamson@redhat.com, linux-metag@vger.kernel.org, Michal Simek , linux-parisc@vger.kernel.org, vgupta@synopsys.com, "linux-kernel@vger.kernel.org" , linux-alpha@vger.kernel.org, Linux Media Mailing List , li On Thu, Aug 13, 2015 at 09:37:37AM +1000, Julian Calaby wrote: > I.e. ~90% of this patch set seems to be just mechanically dropping > BUG_ON()s and converting open coded stuff to use accessor functions > (which should be macros or get inlined, right?) - and the remaining > bit is not flushing if we don't have a physical page somewhere. Which is was 90%. By lines changed most actually is the diffs for the cache flushing. > Would it make sense to split this patch set into a few bits: one to > drop all the useless BUG_ON()s, one to convert all the open coded > stuff to accessor functions, then another to do the actual page-less > sg stuff? Without the ifs the BUG_ON() actually are useful to assert we never feed the sort of physical addresses we can't otherwise support, so I don't think that part is doable. A simple series to make more use of sg_phys and add sg_pfn might still be useful, though.