[PATCH 04/75] perf map: Remove extra indirection from map__find()

Arnaldo Carvalho de Melo
2018-12-06T21:26:49Z

From: Eric Saint-Etienne <eric.saint.etienne@oracle.com>

A double pointer is used in map__find() where a single pointer is enough
because the function doesn't affect the rbtree and the rbtree is locked.

Signed-off-by: Eric Saint-Etienne <eric.saint.etienne@oracle.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Eric Saint-Etienne <eric.saintetienne@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1542969759-24346-1-git-send-email-eric.saint.etienne@oracle.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/map.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 781eed8e3265..a0d58b4d9c32 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -873,19 +873,18 @@ void maps__remove(struct maps *maps, struct map *map)

struct map *maps__find(struct maps *maps, u64 ip)
{
- struct rb_node **p, *parent = NULL;
+ struct rb_node *p;
struct map *m;

down_read(&maps->lock);

- p = &maps->entries.rb_node;
- while (*p != NULL) {
- parent = *p;
- m = rb_entry(parent, struct map, rb_node);
+ p = maps->entries.rb_node;
+ while (p != NULL) {
+ m = rb_entry(p, struct map, rb_node);
if (ip < m->start)
- p = &(*p)->rb_left;
+ p = p->rb_left;
else if (ip >= m->end)
- p = &(*p)->rb_right;
+ p = p->rb_right;
else
goto out;
}
--
2.19.2