From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751946AbaL3HQe (ORCPT ); Tue, 30 Dec 2014 02:16:34 -0500 Received: from mailout3.w1.samsung.com ([210.118.77.13]:48101 "EHLO mailout3.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751495AbaL3HQd (ORCPT ); Tue, 30 Dec 2014 02:16:33 -0500 X-AuditID: cbfec7f4-b7f126d000001e9a-0d-54a2514e0dd2 Message-id: <54A25135.5030103@samsung.com> Date: Tue, 30 Dec 2014 08:16:05 +0100 From: Andrzej Hajda User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-version: 1.0 To: Andi Kleen Cc: linux-mm@kvack.org, Marek Szyprowski , linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 0/4] kstrdup optimization References: <1419864510-24834-1-git-send-email-a.hajda@samsung.com> <87egrhws89.fsf@tassilo.jf.intel.com> In-reply-to: <87egrhws89.fsf@tassilo.jf.intel.com> Content-type: text/plain; charset=windows-1252 Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrKLMWRmVeSWpSXmKPExsVy+t/xa7p+gYtCDPpemFscufad3eLyrjls FvfW/Ge1WHvkLrsDi8f8nR8ZPTZ9msTu0bdlFaPH501yASxRXDYpqTmZZalF+nYJXBlfm6+z FnxirZjz5hNLA+Mdli5GTg4JAROJrY8vM0PYYhIX7q1n62Lk4hASWMoosenfWbAiIYFPjBLH piqB2LwCWhInNn9k6mLk4GARUJU4+FQUJMwmoCnxd/NNNhBbVCBC4sOqr2wQ5YISPybfYwEp FxFQkTh+ig8kzCyQLPH8xzp2EFtYwFBixe9lbBCbsiWe3jgIZnMKGEms+v2YFaSVWUBP4v5F LYhWeYnNa94yT2AUmIVkwSyEqllIqhYwMq9iFE0tTS4oTkrPNdQrTswtLs1L10vOz93ECAna LzsYFx+zOsQowMGoxMO74f3CECHWxLLiytxDjBIczEoivI0Gi0KEeFMSK6tSi/Lji0pzUosP MTJxcEo1MLp9UxKdKV91uliijzu++VKj7+qjf1x5VM7kfd6zXLjPtW6616R5VnNu8faJdt1x CvH8sfCpRPaCpRUOzlcX588zu/W31D1559HMXuMgxY/qLU334xuT3oTO89zb+DMs+FP8pTLu Wo/48mfrJ1V7HuC4v/GgAfufpwbvnG8VM36o498o29DQpMRSnJFoqMVcVJwIAPPsvmo4AgAA Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/30/2014 07:45 AM, Andi Kleen wrote: > Andrzej Hajda writes: > >> kstrdup if often used to duplicate strings where neither source neither >> destination will be ever modified. In such case we can just reuse the source >> instead of duplicating it. The problem is that we must be sure that >> the source is non-modifiable and its life-time is long enough. > What happens if someone is to kfree() these strings? > > -Andi > kstrdup_const must be accompanied by kfree_const, I did not mention it in cover letter but it is described in the 1st patch commit message. Simpler alternative (but I am not sure if better) would be to add similar check (ie. if pointer is in .rodata) to kfree itself. Regards Andrzej