[PATCH v2 05/13] perf header: revamp do_write

[David Carrillo-Cisneros]

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

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

Signed-off-by: David Carrillo-Cisneros <davidcc@xxxxxxxxxx>
---
 tools/perf/util/build-id.c |  2 +-
 tools/perf/util/header.c   | 14 +++++---------
 tools/perf/util/header.h   |  2 ++
 3 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index 168cc49654e7..84d2ea51e557 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -345,7 +345,7 @@ static int write_buildid(const char *name, size_t name_len, u8 *build_id,
 	b.header.misc = misc;
 	b.header.size = sizeof(b) + len;
 
-	err = writen(fd, &b, sizeof(b));
+	err = do_write(fd, &b, sizeof(b));
 	if (err < 0)
 		return err;
 
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 6890f7c51814..292fb2156a59 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -73,17 +73,13 @@ 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;
 }
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index d30109b421ee..e98489c8bba7 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -144,6 +144,8 @@ bool is_perf_magic(u64 magic);
 
 #define NAME_ALIGN 64
 
+int do_write(int fd, const void *buf, size_t size);
+
 int write_padded(int fd, const void *bf, size_t count, size_t count_aligned);
 
 /*
-- 
2.13.0.219.gdb65acc882-goog