From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757687Ab3K1Ka5 (ORCPT ); Thu, 28 Nov 2013 05:30:57 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55115 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751151Ab3K1Ka4 (ORCPT ); Thu, 28 Nov 2013 05:30:56 -0500 From: Jiri Olsa To: linux-kernel@vger.kernel.org Cc: Jiri Olsa , Ingo Molnar , Frederic Weisbecker , Peter Zijlstra , Namhyung Kim , Mike Galbraith , David Ahern , Adrian Hunter , Arnaldo Carvalho de Melo Subject: [PATCH 3/7] perf tools: Fine tune readn function Date: Thu, 28 Nov 2013 11:30:15 +0100 Message-Id: <1385634619-8129-4-git-send-email-jolsa@redhat.com> In-Reply-To: <1385634619-8129-1-git-send-email-jolsa@redhat.com> References: <1385634619-8129-1-git-send-email-jolsa@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Added a 'left' variable to make the flow clearer, and added a debug check for the return value - returning 'n' is more obvious. Added small comment for readn. Original-patch-by: Ingo Molnar Signed-off-by: Jiri Olsa Cc: Ingo Molnar Cc: Frederic Weisbecker Cc: Peter Zijlstra Cc: Namhyung Kim Cc: Mike Galbraith Cc: David Ahern Cc: Adrian Hunter Cc: Arnaldo Carvalho de Melo --- tools/perf/util/util.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c index 9440481..6ea0b4a 100644 --- a/tools/perf/util/util.c +++ b/tools/perf/util/util.c @@ -6,6 +6,7 @@ #endif #include #include +#include /* * XXX We need to find a better place for these things... @@ -151,21 +152,26 @@ unsigned long convert_unit(unsigned long value, char *unit) return value; } +/* + * Read exactly 'n' bytes or return an error. + */ ssize_t readn(int fd, void *buf, size_t n) { void *buf_start = buf; + size_t left = n; - while (n) { - ssize_t ret = read(fd, buf, n); + while (left) { + ssize_t ret = read(fd, buf, left); if (ret <= 0) return ret; - n -= ret; - buf += ret; + left -= ret; + buf += ret; } - return buf - buf_start; + BUG_ON((size_t)(buf - buf_start) != n); + return n; } size_t hex_width(u64 v) -- 1.8.3.1