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Subject[tip:perf/urgent] perf mmap: Add new return value logic for perf_mmap__read_init()
Commit-ID:  e0c75323e9f7002d84abbf68650277a6d971b3c0
Gitweb: https://git.kernel.org/tip/e0c75323e9f7002d84abbf68650277a6d971b3c0
Author: Kan Liang <kan.liang@intel.com>
AuthorDate: Thu, 18 Jan 2018 13:26:20 -0800
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Tue, 6 Feb 2018 10:11:49 -0300

perf mmap: Add new return value logic for perf_mmap__read_init()

Improve the readability by using meaningful enum (-EAGAIN, -EINVAL and
0) to replace the three returning states (0, -1 and 1).

Suggested-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1516310792-208685-6-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/mmap.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index c19a4e6..38fa69d 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -282,7 +282,7 @@ int perf_mmap__read_init(struct perf_mmap *md, bool overwrite,
*endp = overwrite ? old : head;

if (*startp == *endp)
- return 0;
+ return -EAGAIN;

size = *endp - *startp;
if (size > (unsigned long)(md->mask) + 1) {
@@ -291,7 +291,7 @@ int perf_mmap__read_init(struct perf_mmap *md, bool overwrite,

md->prev = head;
perf_mmap__consume(md, overwrite);
- return 0;
+ return -EAGAIN;
}

/*
@@ -299,10 +299,10 @@ int perf_mmap__read_init(struct perf_mmap *md, bool overwrite,
* most of data from it.
*/
if (overwrite_rb_find_range(data, md->mask, head, startp, endp))
- return -1;
+ return -EINVAL;
}

- return 1;
+ return 0;
}

int perf_mmap__push(struct perf_mmap *md, bool overwrite,
@@ -316,8 +316,8 @@ int perf_mmap__push(struct perf_mmap *md, bool overwrite,
int rc = 0;

rc = perf_mmap__read_init(md, overwrite, &start, &end);
- if (rc < 1)
- return rc;
+ if (rc < 0)
+ return (rc == -EAGAIN) ? 0 : -1;

size = end - start;

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