From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga05.intel.com ([192.55.52.43]:58085 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728741AbeGYSfz (ORCPT ); Wed, 25 Jul 2018 14:35:55 -0400 Date: Wed, 25 Jul 2018 11:23:16 -0600 From: Ross Zwisler To: Huaisheng Ye Cc: linux-nvdimm@lists.01.org, dan.j.williams@intel.com, ross.zwisler@linux.intel.com, willy@infradead.org, vishal.l.verma@intel.com, dave.jiang@intel.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, viro@zeniv.linux.org.uk, martin.petersen@oracle.com, axboe@kernel.dk, gregkh@linuxfoundation.org, bart.vanassche@wdc.com, jack@suse.cz, agk@redhat.com, snitzer@redhat.com, dm-devel@redhat.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, linux-fsdevel@vger.kernel.org, chengnt@lenovo.com, colyli@suse.de, Huaisheng Ye Subject: Re: [PATCH v2 0/6] kaddr and pfn can be NULL to ->direct_access() Message-ID: <20180725172316.GA12896@linux.intel.com> References: <20180725162849.8320-1-yehs2007@zoho.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180725162849.8320-1-yehs2007@zoho.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, Jul 26, 2018 at 12:28:43AM +0800, Huaisheng Ye wrote: > From: Huaisheng Ye > > Changes since v1 [1]: > * Involve the previous patches for pfn can be NULL. > * Reword the patch descriptions according to Christian's comment. > * According to Ross's suggestion, replace local pointer dummy_addr > with NULL within md/dm-writecache for direct_access. > > [1]: https://lkml.org/lkml/2018/7/24/199 > > Some functions within fs/dax, dax/super and md/dm-writecache don't > need to get local pointer kaddr or variable pfn from direct_access. > Assigning NULL to kaddr or pfn to ->direct_access() is more > straightforward and simple than offering a useless local pointer or > variable. > > So all ->direct_access() need to check the validity of pointer kaddr > and pfn for NULL assignment. If either of them is equal to NULL, that > is to say callers may have no need for kaddr or pfn, so this series of > patch are prepared for allowing them to pass in NULL instead of having > to pass in a local pointer or variable that they then just throw away. Looks good. For the series: Reviewed-by: Ross Zwisler