From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Jiang Subject: Re: [PATCH v3 0/6] kaddr and pfn can be NULL to ->direct_access() Date: Tue, 31 Jul 2018 08:35:58 -0700 Message-ID: References: <20180730071548.9172-1-yehs2007@zoho.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180730071548.9172-1-yehs2007@zoho.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Huaisheng Ye , linux-nvdimm@lists.01.org, dan.j.williams@intel.com Cc: ross.zwisler@linux.intel.com, willy@infradead.org, vishal.l.verma@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, keescook@chromium.org, dm-devel@redhat.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, linux-fsdevel@vger.kernel.org, colyli@suse.de, chengnt@lenovo.com, Huaisheng Ye List-ID: On 7/30/2018 12:15 AM, Huaisheng Ye wrote: Applied > From: Huaisheng Ye > > Changes since v2 [2]: > * Collect Martin and Mike's acks for dcssblk and dm-writecache; > * Rebase the series of patch to v4.18-rc7. > > 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 > [2]: https://lkml.org/lkml/2018/7/25/581 > > 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 with ->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. > > Huaisheng Ye (6): > libnvdimm, pmem: kaddr and pfn can be NULL to ->direct_access() > s390, dcssblk: kaddr and pfn can be NULL to ->direct_access() > tools/testing/nvdimm: kaddr and pfn can be NULL to ->direct_access() > dax/super: Do not request a pointer kaddr when not required > md/dm-writecache: Don't request pointer dummy_addr when not required > filesystem-dax: Do not request kaddr and pfn when not required > > drivers/dax/super.c | 3 +-- > drivers/md/dm-writecache.c | 3 +-- > drivers/nvdimm/pmem.c | 7 +++++-- > drivers/s390/block/dcssblk.c | 8 +++++--- > fs/dax.c | 13 ++++--------- > tools/testing/nvdimm/pmem-dax.c | 12 ++++++++---- > 6 files changed, 24 insertions(+), 22 deletions(-) >