libperf: Add 'refcnt' to struct perf_mmap

Move 'refcnt' from tools/perf's mmap to libperf's perf_mmap struct.

Committer notes:

Add the refcount.h include directive here, now it is needed.
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 <a.p.zijlstra@chello.nl>
Link: http://lore.kernel.org/lkml/20190913132355.21634-15-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/lib/include/internal/mmap.h

@@ -2,6 +2,8 @@
 #ifndef __LIBPERF_INTERNAL_MMAP_H
 #define __LIBPERF_INTERNAL_MMAP_H
 
+#include <linux/refcount.h>
+
 /**
  * struct perf_mmap - perf's ring buffer mmap details
  *
@@ -12,6 +14,7 @@ struct perf_mmap {
 	int		 mask;
 	int		 fd;
 	int		 cpu;
+	refcount_t	 refcnt;
 };
 
 #endif /* __LIBPERF_INTERNAL_MMAP_H */

tools/perf/util/evlist.c

@@ -719,7 +719,7 @@ static struct mmap *evlist__alloc_mmap(struct evlist *evlist,
 		 * Each PERF_EVENT_IOC_SET_OUTPUT points to this mmap and
 		 * thus does perf_mmap__get() on it.
 		 */
-		refcount_set(&map[i].refcnt, 0);
+		refcount_set(&map[i].core.refcnt, 0);
 	}
 	return map;
 }

tools/perf/util/mmap.c

@@ -89,7 +89,7 @@ union perf_event *perf_mmap__read_event(struct mmap *map)
 	/*
 	 * Check if event was unmapped due to a POLLHUP/POLLERR.
 	 */
-	if (!refcount_read(&map->refcnt))
+	if (!refcount_read(&map->core.refcnt))
 		return NULL;
 
 	/* non-overwirte doesn't pause the ringbuffer */
@@ -111,14 +111,14 @@ static bool perf_mmap__empty(struct mmap *map)
 
 void perf_mmap__get(struct mmap *map)
 {
-	refcount_inc(&map->refcnt);
+	refcount_inc(&map->core.refcnt);
 }
 
 void perf_mmap__put(struct mmap *map)
 {
-	BUG_ON(map->core.base && refcount_read(&map->refcnt) == 0);
+	BUG_ON(map->core.base && refcount_read(&map->core.refcnt) == 0);
 
-	if (refcount_dec_and_test(&map->refcnt))
+	if (refcount_dec_and_test(&map->core.refcnt))
 		perf_mmap__munmap(map);
 }
 
@@ -130,7 +130,7 @@ void perf_mmap__consume(struct mmap *map)
 		perf_mmap__write_tail(map, old);
 	}
 
-	if (refcount_read(&map->refcnt) == 1 && perf_mmap__empty(map))
+	if (refcount_read(&map->core.refcnt) == 1 && perf_mmap__empty(map))
 		perf_mmap__put(map);
 }
 
@@ -321,7 +321,7 @@ void perf_mmap__munmap(struct mmap *map)
 		munmap(map->core.base, perf_mmap__mmap_len(map));
 		map->core.base = NULL;
 		map->core.fd = -1;
-		refcount_set(&map->refcnt, 0);
+		refcount_set(&map->core.refcnt, 0);
 	}
 	auxtrace_mmap__munmap(&map->auxtrace_mmap);
 }
@@ -367,7 +367,7 @@ int perf_mmap__mmap(struct mmap *map, struct mmap_params *mp, int fd, int cpu)
 	 * evlist layer can't just drop it when filtering events in
 	 * perf_evlist__filter_pollfd().
 	 */
-	refcount_set(&map->refcnt, 2);
+	refcount_set(&map->core.refcnt, 2);
 	map->prev = 0;
 	map->core.mask = mp->mask;
 	map->core.base = mmap(NULL, perf_mmap__mmap_len(map), mp->prot,
@@ -479,7 +479,7 @@ int perf_mmap__read_init(struct mmap *map)
 	/*
 	 * Check if event was unmapped due to a POLLHUP/POLLERR.
 	 */
-	if (!refcount_read(&map->refcnt))
+	if (!refcount_read(&map->core.refcnt))
 		return -ENOENT;
 
 	return __perf_mmap__read_init(map);
@@ -537,7 +537,7 @@ void perf_mmap__read_done(struct mmap *map)
 	/*
 	 * Check if event was unmapped due to a POLLHUP/POLLERR.
 	 */
-	if (!refcount_read(&map->refcnt))
+	if (!refcount_read(&map->core.refcnt))
 		return;
 
 	map->prev = perf_mmap__read_head(map);

tools/perf/util/mmap.h

@@ -22,7 +22,6 @@ struct aiocb;
  */
 struct mmap {
 	struct perf_mmap	core;
-	refcount_t	 refcnt;
 	u64		 prev;
 	u64		 start;
 	u64		 end;