libperf: Adopt perf_mmap__put() function from tools/perf

Move perf_mmap__put() from tools/perf to libperf.

Once perf_mmap__put() is moved, we need a way to call application
related unmap code (AIO and aux related code for eprf), when the map
goes away.

Add the perf_mmap::unmap callback to do that.

The unmap path from perf is:

  perf_mmap__put                           (libperf)
    perf_mmap__munmap                      (libperf)
      map->unmap_cb -> perf_mmap__unmap_cb (perf)
        mmap__munmap                       (perf)

Committer notes:

Add missing linux/kernel.h to tools/perf/lib/mmap.c to get the BUG_ON
definition.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20191007125344.14268-8-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 33 insertions, 13 deletions

diff --git a/tools/perf/lib/include/internal/mmap.h b/tools/perf/lib/include/internal/mmap.h
index 5c2ca9ab12cd..bf9cc7d005ab 100644
--- a/tools/perf/lib/include/internal/mmap.h
+++ b/tools/perf/lib/include/internal/mmap.h
@@ -10,23 +10,28 @@
 /* perf sample has 16 bits size limit */
 #define PERF_SAMPLE_MAX_SIZE (1 << 16)
 
+struct perf_mmap;
+
+typedef void (*libperf_unmap_cb_t)(struct perf_mmap *map);
+
 /**
  * struct perf_mmap - perf's ring buffer mmap details
  *
  * @refcnt - e.g. code using PERF_EVENT_IOC_SET_OUTPUT to share this
  */
 struct perf_mmap {
-	void		*base;
-	int		 mask;
-	int		 fd;
-	int		 cpu;
-	refcount_t	 refcnt;
-	u64		 prev;
-	u64		 start;
-	u64		 end;
-	bool		 overwrite;
-	u64		 flush;
-	char		 event_copy[PERF_SAMPLE_MAX_SIZE] __aligned(8);
+	void			*base;
+	int			 mask;
+	int			 fd;
+	int			 cpu;
+	refcount_t		 refcnt;
+	u64			 prev;
+	u64			 start;
+	u64			 end;
+	bool			 overwrite;
+	u64			 flush;
+	libperf_unmap_cb_t	 unmap_cb;
+	char			 event_copy[PERF_SAMPLE_MAX_SIZE] __aligned(8);
 };
 
 struct perf_mmap_param {
@@ -36,10 +41,12 @@ struct perf_mmap_param {
 
 size_t perf_mmap__mmap_len(struct perf_mmap *map);
 
-void perf_mmap__init(struct perf_mmap *map, bool overwrite);
+void perf_mmap__init(struct perf_mmap *map, bool overwrite,
+		     libperf_unmap_cb_t unmap_cb);
 int perf_mmap__mmap(struct perf_mmap *map, struct perf_mmap_param *mp,
 		    int fd, int cpu);
 void perf_mmap__munmap(struct perf_mmap *map);
 void perf_mmap__get(struct perf_mmap *map);
+void perf_mmap__put(struct perf_mmap *map);
 
 #endif /* __LIBPERF_INTERNAL_MMAP_H */
diff --git a/tools/perf/lib/mmap.c b/tools/perf/lib/mmap.c
index 6eb228d89206..89c1e0e8b897 100644
--- a/tools/perf/lib/mmap.c
+++ b/tools/perf/lib/mmap.c
@@ -2,11 +2,14 @@
 #include <sys/mman.h>
 #include <internal/mmap.h>
 #include <internal/lib.h>
+#include <linux/kernel.h>
 
-void perf_mmap__init(struct perf_mmap *map, bool overwrite)
+void perf_mmap__init(struct perf_mmap *map, bool overwrite,
+		     libperf_unmap_cb_t unmap_cb)
 {
 	map->fd = -1;
 	map->overwrite = overwrite;
+	map->unmap_cb  = unmap_cb;
 	refcount_set(&map->refcnt, 0);
 }
 
@@ -40,9 +43,19 @@ void perf_mmap__munmap(struct perf_mmap *map)
 		map->fd = -1;
 		refcount_set(&map->refcnt, 0);
 	}
+	if (map && map->unmap_cb)
+		map->unmap_cb(map);
 }
 
 void perf_mmap__get(struct perf_mmap *map)
 {
 	refcount_inc(&map->refcnt);
 }
+
+void perf_mmap__put(struct perf_mmap *map)
+{
+	BUG_ON(map->base && refcount_read(&map->refcnt) == 0);
+
+	if (refcount_dec_and_test(&map->refcnt))
+		perf_mmap__munmap(map);
+}