From: Ross Zwisler Subject: Re: [PATCH 2/2] ext2: Add locking for DAX faults Date: Tue, 13 Oct 2015 16:15:30 -0600 Message-ID: <20151013221530.GA17773@linux.intel.com> References: <1444428128-12200-1-git-send-email-ross.zwisler@linux.intel.com> <1444428128-12200-3-git-send-email-ross.zwisler@linux.intel.com> <20151011231443.GY27164@dastard> <20151012214135.GA24720@linux.intel.com> <20151012232427.GH27164@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Dave Chinner , Ross Zwisler , Kernel development list , Jan Kara , linux-ext4@vger.kernel.org, Dan Williams , linux-nvdimm@lists.01.org, Matthew Wilcox , Andreas Dilger To: Eric Curtin Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Tue, Oct 13, 2015 at 12:35:44AM +0100, Eric Curtin wrote: > Hi Ross, >=20 > For all those int ret declarations. Why not declare and initialize al= l > on the same line? >=20 > Regards, > Eric Because the return value 'ret' is set unconditionally later in the func= tion as part of a call into the DAX code. This call needs to be made after we'= ve done appropriate locking, though, which really is the point of the ext2 wrap= per for the DAX function. Setting it to some random value and then uncondition= ally overwriting it later in the function is a bad pattern because a) the in= itial value is meaningless and b) it can hide coding errors where you are no = longer setting the variable to something meaningful. The "warning: =E2=80=98r= et=E2=80=99 is used uninitialized in this function" warnings would otherwise warn you that = you've made a mistake.