From: Dan Williams Subject: Re: [PATCH 4/5] dax: use sb_issue_zerout instead of calling dax_clear_sectors Date: Tue, 29 Mar 2016 12:37:14 -0700 Message-ID: References: <1458861450-17705-1-git-send-email-vishal.l.verma@intel.com> <1458861450-17705-5-git-send-email-vishal.l.verma@intel.com> <1458939796.5501.8.camel@intel.com> <1459195288.15523.3.camel@intel.com> <1459277829.6412.3.camel@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: "linux-block@vger.kernel.org" , "xfs@oss.sgi.com" , "linux-mm@kvack.org" , "viro@zeniv.linux.org.uk" , "axboe@fb.com" , "akpm@linux-foundation.org" , "linux-nvdimm@lists.01.org" , "linux-fsdevel@vger.kernel.org" , "ross.zwisler@linux.intel.com" , "linux-ext4@vger.kernel.org" , "Wilcox, Matthew R" , "david@fromorbit.com" , "jack@suse.cz" To: "Verma, Vishal L" Return-path: In-Reply-To: <1459277829.6412.3.camel@intel.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Tue, Mar 29, 2016 at 11:57 AM, Verma, Vishal L wrote: > On Mon, 2016-03-28 at 16:34 -0700, Dan Williams wrote: > > <> > >> Seems kind of sad to fail the fault due to a bad block when we were >> going to zero it anyway, right? I'm not seeing a compelling reason to >> keep any zeroing in fs/dax.c. > > Agreed - but how do we do this? clear_pmem needs to be able to clear an > arbitrary number of bytes, but to go through the driver, we'd need to > send down a bio? If only the driver had an rw_bytes like interface that > could be used by anyone... :) I think we're ok because clear_pmem() will always happen on PAGE_SIZE, or HPAGE_SIZE boundaries.