From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kulikov Vasiliy Date: Mon, 06 Sep 2010 14:18:13 +0000 Subject: Re: [PATCH 13/14] mm: mempolicy: Check return code of check_range Message-Id: <20100906141813.GB9632@albatros> List-Id: References: <1283711588-7628-1-git-send-email-segooon@gmail.com> <20100906093610.C8B5.A69D9226@jp.fujitsu.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: David Rientjes Cc: KOSAKI Motohiro , kernel-janitors@vger.kernel.org, Andrew Morton , Lee Schermerhorn , Christoph Lameter , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Mon, Sep 06, 2010 at 02:02 -0700, David Rientjes wrote: > On Mon, 6 Sep 2010, KOSAKI Motohiro wrote: > > > > From: Vasiliy Kulikov > > > > > > Function check_range may return ERR_PTR(...). Check for it. > > > > When happen this issue? > > > > afaik, check_range return error when following condition. > > 1) mm->mmap->vm_start argument is incorrect > > 2) don't have neigher MPOL_MF_STATS, MPOL_MF_MOVE and MPOL_MF_MOVE_ALL > > > > I think both case is not happen in real. Am I overlooking anything? > > > > There's no reason not to check the return value of a function when the > implementation of either could change at any time. migrate_to_node() is > certainly not in any fastpath where we can't sacrifice a branch for more > robust code. Agreed, if you know that the caller must check input data and must not check return code, it's better to make this function return void. -- Vasiliy