[PATCH v6 05/16] perf header: revamp do_write

[David Carrillo-Cisneros]

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 <davi...@google.com>
---
 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 e9665150e9b1..4baa5329439f 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -304,7 +304,7 @@ 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 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;
 }
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);
 
 /*
-- 
2.13.2.932.g7449e964c-goog