libperf: Adopt perf_mmap__read_init() from tools/perf

Move perf_mmap__read_init() from tools/perf to libperf and export it in
perf/mmap.h header.

And add pr_debug2()/pr_debug3() macros support, because the code is
using them.

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/20191007125344.14268-11-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 1 insertions, 81 deletions

diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index abe7cbe6c95f..59379118c2f1 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -365,86 +365,6 @@ int mmap__mmap(struct mmap *map, struct mmap_params *mp, int fd, int cpu)
 	return perf_mmap__aio_mmap(map, mp);
 }
 
-static int overwrite_rb_find_range(void *buf, int mask, u64 *start, u64 *end)
-{
-	struct perf_event_header *pheader;
-	u64 evt_head = *start;
-	int size = mask + 1;
-
-	pr_debug2("%s: buf=%p, start=%"PRIx64"\n", __func__, buf, *start);
-	pheader = (struct perf_event_header *)(buf + (*start & mask));
-	while (true) {
-		if (evt_head - *start >= (unsigned int)size) {
-			pr_debug("Finished reading overwrite ring buffer: rewind\n");
-			if (evt_head - *start > (unsigned int)size)
-				evt_head -= pheader->size;
-			*end = evt_head;
-			return 0;
-		}
-
-		pheader = (struct perf_event_header *)(buf + (evt_head & mask));
-
-		if (pheader->size == 0) {
-			pr_debug("Finished reading overwrite ring buffer: get start\n");
-			*end = evt_head;
-			return 0;
-		}
-
-		evt_head += pheader->size;
-		pr_debug3("move evt_head: %"PRIx64"\n", evt_head);
-	}
-	WARN_ONCE(1, "Shouldn't get here\n");
-	return -1;
-}
-
-/*
- * Report the start and end of the available data in ringbuffer
- */
-static int __perf_mmap__read_init(struct mmap *md)
-{
-	u64 head = perf_mmap__read_head(&md->core);
-	u64 old = md->core.prev;
-	unsigned char *data = md->core.base + page_size;
-	unsigned long size;
-
-	md->core.start = md->core.overwrite ? head : old;
-	md->core.end = md->core.overwrite ? old : head;
-
-	if ((md->core.end - md->core.start) < md->core.flush)
-		return -EAGAIN;
-
-	size = md->core.end - md->core.start;
-	if (size > (unsigned long)(md->core.mask) + 1) {
-		if (!md->core.overwrite) {
-			WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n");
-
-			md->core.prev = head;
-			perf_mmap__consume(&md->core);
-			return -EAGAIN;
-		}
-
-		/*
-		 * Backward ring buffer is full. We still have a chance to read
-		 * most of data from it.
-		 */
-		if (overwrite_rb_find_range(data, md->core.mask, &md->core.start, &md->core.end))
-			return -EINVAL;
-	}
-
-	return 0;
-}
-
-int perf_mmap__read_init(struct mmap *map)
-{
-	/*
-	 * Check if event was unmapped due to a POLLHUP/POLLERR.
-	 */
-	if (!refcount_read(&map->core.refcnt))
-		return -ENOENT;
-
-	return __perf_mmap__read_init(map);
-}
-
 int perf_mmap__push(struct mmap *md, void *to,
 		    int push(struct mmap *map, void *to, void *buf, size_t size))
 {
@@ -454,7 +374,7 @@ int perf_mmap__push(struct mmap *md, void *to,
 	void *buf;
 	int rc = 0;
 
-	rc = perf_mmap__read_init(md);
+	rc = perf_mmap__read_init(&md->core);
 	if (rc < 0)
 		return (rc == -EAGAIN) ? 1 : -1;