From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnaldo Carvalho de Melo Subject: [PATCH 67/86] perf util: Add const modifier to buf in "writen" function Date: Wed, 19 Jul 2017 11:29:31 -0300 Message-ID: <20170719142950.3747-68-acme@kernel.org> References: <20170719142950.3747-1-acme@kernel.org> Return-path: In-Reply-To: <20170719142950.3747-1-acme@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, David Carrillo-Cisneros , Alexander Shishkin , Andi Kleen , He Kuang , Masami Hiramatsu , Namhyung Kim , Paul Turner , Peter Zijlstra , Simon Que , Stephane Eranian , Wang Nan , Arnaldo Carvalho de Melo List-Id: linux-perf-users.vger.kernel.org From: David Carrillo-Cisneros 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 Acked-by: David Ahern Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Andi Kleen Cc: He Kuang Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Paul Turner Cc: Peter Zijlstra Cc: Simon Que Cc: Stephane Eranian Cc: Wang Nan Link: http://lkml.kernel.org/r/20170718042549.145161-5-davidcc@google.com Signed-off-by: Arnaldo Carvalho de Melo --- 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 9e4ea852f636..4c360daa4e24 100644 --- a/tools/perf/util/util.c +++ b/tools/perf/util/util.c @@ -281,6 +281,7 @@ 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); @@ -308,9 +309,10 @@ 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 062dd20437f7..b136c271125f 100644 --- a/tools/perf/util/util.h +++ b/tools/perf/util/util.h @@ -38,7 +38,7 @@ int copyfile_ns(const char *from, const char *to, struct nsinfo *nsi); 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); size_t hex_width(u64 v); int hex2u64(const char *ptr, u64 *val); -- 2.9.4