[PATCH 3/5] perf tools: reuse perf_mmap__read_catchup in perf_mmap__push

[kan . liang]

From: Kan Liang <kan.li...@intel.com>

perf_mmap__push uses the same codes as perf_mmap__read_catchup to
calculate the ring buffer start, end and size.

No funcational change.

Signed-off-by: Kan Liang <kan.li...@intel.com>
---
 tools/perf/util/mmap.c | 31 ++++++-------------------------
 1 file changed, 6 insertions(+), 25 deletions(-)

diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index bf67460..61237eb 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -285,36 +285,16 @@ int perf_mmap__push(struct perf_mmap *md, bool overwrite,
                    void *to, int push(void *to, void *buf, size_t size))
 {
        u64 head = perf_mmap__read_head(md);
-       u64 old = md->prev;
-       u64 end = head, start = old;
+       u64 end, start;
        unsigned char *data = md->base + page_size;
        unsigned long size;
        void *buf;
-       int rc = 0;
+       int rc;
 
-       start = overwrite ? head : old;
-       end = overwrite ? old : head;
 
-       if (start == end)
-               return 0;
-
-       size = end - start;
-       if (size > (unsigned long)(md->mask) + 1) {
-               if (!overwrite) {
-                       WARN_ONCE(1, "failed to keep up with mmap data. (warn 
only once)\n");
-
-                       md->prev = head;
-                       perf_mmap__consume(md, overwrite);
-                       return 0;
-               }
-
-               /*
-                * Backward ring buffer is full. We still have a chance to read
-                * most of data from it.
-                */
-               if (overwrite_rb_find_range(data, md->mask, head, &start, &end))
-                       return -1;
-       }
+       rc = perf_mmap__read_catchup(md, overwrite, &start, &end, &size);
+       if (rc < 1)
+               return rc;
 
        if ((start & md->mask) + size != (end & md->mask)) {
                buf = &data[start & md->mask];
@@ -338,6 +318,7 @@ int perf_mmap__push(struct perf_mmap *md, bool overwrite,
 
        md->prev = head;
        perf_mmap__consume(md, overwrite);
+       rc = 0;
 out:
        return rc;
 }
-- 
2.5.5