Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932125AbaA3VvQ (ORCPT ); Thu, 30 Jan 2014 16:51:16 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:42911 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753855AbaA3VvN (ORCPT ); Thu, 30 Jan 2014 16:51:13 -0500 Date: Thu, 30 Jan 2014 13:51:11 -0800 From: Andrew Morton To: Sebastian Capella Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pm@vger.kernel.org, linaro-kernel@lists.linaro.org, patches@linaro.org, "Joe Perches" , "Mikulas Patocka" , "Michel Lespinasse" , "Shaohua Li" , "Jerome Marchand" , "Joonsoo Kim" Subject: Re: [PATCH v5 1/2] mm: add kstrimdup function Message-Id: <20140130135111.cffc7d8852dd38545bddeb75@linux-foundation.org> In-Reply-To: <20140130214545.18296.69349@capellas-linux> References: <1391116318-17253-1-git-send-email-sebastian.capella@linaro.org> <1391116318-17253-2-git-send-email-sebastian.capella@linaro.org> <20140130132251.4f662aeddc09d8410dee4490@linux-foundation.org> <20140130214545.18296.69349@capellas-linux> X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 30 Jan 2014 13:45:45 -0800 Sebastian Capella wrote: > Quoting Andrew Morton (2014-01-30 13:22:51) > > On Thu, 30 Jan 2014 13:11:57 -0800 Sebastian Capella wrote: > > > +char *kstrimdup(const char *s, gfp_t gfp) > > > +{ > > > + char *buf; > > > + char *begin = skip_spaces(s); > > > + size_t len = strlen(begin); > > > + > > > + while (len > 1 && isspace(begin[len - 1])) > > > + len--; > > > > That's off-by-one isn't it? kstrimdup(" ") should return "", not " ". > > > > > + buf = kmalloc_track_caller(len + 1, gfp); > > > + if (!buf) > > > + return NULL; > > > + > > > + memcpy(buf, begin, len); > > > + buf[len] = '\0'; > > > + > > > + return buf; > > > +} > > Hi Andrew, > > I think this is a little tricky. > > For an empty string, the function relies on skip_spaces to point begin > at the \0'. > > Alternately, if we don't have an empty string, we know we have at least 1 > non-space, non-null character at begin[0], and there's no need to check it, > so the loop stops at [1]. If there's a space at 1, we just put the '\0' > there. > > We could check at [0], but I think its already been checked by skip_spaces. heh, OK, tricky. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/