diff options
| author | Jiri Olsa <jolsa@redhat.com> | 2013-11-28 11:30:15 +0100 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2013-12-02 09:22:46 -0300 |
| commit | 838d14520267769648fb2fc2a637107a1d102590 (patch) | |
| tree | 48f16ca6aa41f01ac852114a224f3715578f1b15 | |
| parent | 727ebd544f85285a223ecc6a2a57ef90202cdc7b (diff) | |
perf tools: Fine tune readn function
Added a 'left' variable to make the flow clearer, and added a debug
check for the return value - returning 'n' is more obvious.
Added small comment for readn.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Original-patch-by: Ingo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1385634619-8129-4-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
| -rw-r--r-- | tools/perf/util/util.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c index 9440481e909..6ea0b4ae956 100644 --- a/tools/perf/util/util.c +++ b/tools/perf/util/util.c @@ -6,6 +6,7 @@ #endif #include <stdio.h> #include <stdlib.h> +#include <linux/kernel.h> /* * XXX We need to find a better place for these things... @@ -151,21 +152,26 @@ unsigned long convert_unit(unsigned long value, char *unit) return value; } +/* + * Read exactly 'n' bytes or return an error. + */ ssize_t readn(int fd, void *buf, size_t n) { void *buf_start = buf; + size_t left = n; - while (n) { - ssize_t ret = read(fd, buf, n); + while (left) { + ssize_t ret = read(fd, buf, left); if (ret <= 0) return ret; - n -= ret; - buf += ret; + left -= ret; + buf += ret; } - return buf - buf_start; + BUG_ON((size_t)(buf - buf_start) != n); + return n; } size_t hex_width(u64 v) |