perf header: Revamp do_write()

Now that writen takes a const buffer, use it in do_write instead of
duplicating its functionality.

Export do_write to use it consistently in header.c and build_id.c .

Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Acked-by: David Ahern <dsahern@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Simon Que <sque@chromium.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20170718042549.145161-6-davidcc@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 5 insertions, 9 deletions

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 8dda19b68ac4..954f0ef8e712 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -75,17 +75,13 @@ bool perf_header__has_feat(const struct perf_header *header, int feat)
 }
 
 /* Return: 0 if succeded, -ERR if failed. */
-static int do_write(int fd, const void *buf, size_t size)
+int do_write(int fd, const void *buf, size_t size)
 {
-	while (size) {
-		int ret = write(fd, buf, size);
-
-		if (ret < 0)
-			return -errno;
+	ssize_t ret;
 
-		size -= ret;
-		buf += ret;
-	}
+	ret  = writen(fd, buf, size);
+	if (ret != (ssize_t)size)
+		return ret < 0 ? (int)ret : -1;
 
 	return 0;
 }