From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965109AbdEWHti (ORCPT ); Tue, 23 May 2017 03:49:38 -0400 Received: from mail-pf0-f181.google.com ([209.85.192.181]:35255 "EHLO mail-pf0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936388AbdEWHt3 (ORCPT ); Tue, 23 May 2017 03:49:29 -0400 From: David Carrillo-Cisneros To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Andi Kleen , Simon Que , Wang Nan , Jiri Olsa , He Kuang , Masami Hiramatsu , David Ahern , Namhyung Kim , Stephane Eranian , Paul Turner , David Carrillo-Cisneros Subject: [PATCH v2 04/13] perf util: add const modifier to buf in "writen" function Date: Tue, 23 May 2017 00:48:44 -0700 Message-Id: <20170523074853.54892-5-davidcc@google.com> X-Mailer: git-send-email 2.13.0.219.gdb65acc882-goog In-Reply-To: <20170523074853.54892-1-davidcc@google.com> References: <20170523074853.54892-1-davidcc@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Make buf in helper function "writen" constant to simplify the life of its callers. This requires to hack a cast of buf prior to passing it to "ion" which is simpler than the alternative of reworking the "ion" function to provide a read and a write paths, the latter with constant buf argument. Signed-off-by: David Carrillo-Cisneros --- tools/perf/util/util.c | 6 ++++-- tools/perf/util/util.h | 2 +- 2 files changed, 5 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c index 6450c75a6f5b..31ca7661e5fb 100644 --- a/tools/perf/util/util.c +++ b/tools/perf/util/util.c @@ -260,6 +260,7 @@ static ssize_t ion(bool is_read, int fd, void *buf, size_t n) size_t left = n; while (left) { + /* buf must be treated as const if !is_read. */ ssize_t ret = is_read ? read(fd, buf, left) : write(fd, buf, left); @@ -287,9 +288,10 @@ ssize_t readn(int fd, void *buf, size_t n) /* * Write exactly 'n' bytes or return an error. */ -ssize_t writen(int fd, void *buf, size_t n) +ssize_t writen(int fd, const void *buf, size_t n) { - return ion(false, fd, buf, n); + /* ion does not modify buf. */ + return ion(false, fd, (void *)buf, n); } size_t hex_width(u64 v) diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h index 3852b6d3270a..e0881bf67fc9 100644 --- a/tools/perf/util/util.h +++ b/tools/perf/util/util.h @@ -57,7 +57,7 @@ int copyfile_mode(const char *from, const char *to, mode_t mode); int copyfile_offset(int fromfd, loff_t from_ofs, int tofd, loff_t to_ofs, u64 size); ssize_t readn(int fd, void *buf, size_t n); -ssize_t writen(int fd, void *buf, size_t n); +ssize_t writen(int fd, const void *buf, size_t n); struct perf_event_attr; -- 2.13.0.219.gdb65acc882-goog