From: Christy Lee <christylee@fb.com>
Date: Wed, 29 Dec 2021 12:41:56 -0800
Subject: libbpf: Deprecate bpf_perf_event_read_simple() API
Patch-mainline: v5.17-rc1
Git-commit: 7218c28c87f57c131879a75a226b9033ac90b266
References: jsc#PED-1368

With perf_buffer__poll() and perf_buffer__consume() APIs available,
there is no reason to expose bpf_perf_event_read_simple() API to
users. If users need custom perf buffer, they could re-implement
the function.

Mark bpf_perf_event_read_simple() and move the logic to a new
static function so it can still be called by other functions in the
same file.

  [0] Closes: https://github.com/libbpf/libbpf/issues/310

Signed-off-by: Christy Lee <christylee@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211229204156.13569-1-christylee@fb.com
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 tools/lib/bpf/libbpf.c |   22 ++++++++++++++--------
 tools/lib/bpf/libbpf.h |    1 +
 2 files changed, 15 insertions(+), 8 deletions(-)

--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -10660,10 +10660,10 @@ struct bpf_link *bpf_map__attach_struct_
 	return link;
 }
 
-enum bpf_perf_event_ret
-bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
-			   void **copy_mem, size_t *copy_size,
-			   bpf_perf_event_print_t fn, void *private_data)
+static enum bpf_perf_event_ret
+perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
+		       void **copy_mem, size_t *copy_size,
+		       bpf_perf_event_print_t fn, void *private_data)
 {
 	struct perf_event_mmap_page *header = mmap_mem;
 	__u64 data_head = ring_buffer_read_head(header);
@@ -10708,6 +10708,12 @@ bpf_perf_event_read_simple(void *mmap_me
 	return libbpf_err(ret);
 }
 
+__attribute__((alias("perf_event_read_simple")))
+enum bpf_perf_event_ret
+bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
+			   void **copy_mem, size_t *copy_size,
+			   bpf_perf_event_print_t fn, void *private_data);
+
 struct perf_buffer;
 
 struct perf_buffer_params {
@@ -11116,10 +11122,10 @@ static int perf_buffer__process_records(
 {
 	enum bpf_perf_event_ret ret;
 
-	ret = bpf_perf_event_read_simple(cpu_buf->base, pb->mmap_size,
-					 pb->page_size, &cpu_buf->buf,
-					 &cpu_buf->buf_size,
-					 perf_buffer__process_record, cpu_buf);
+	ret = perf_event_read_simple(cpu_buf->base, pb->mmap_size,
+				     pb->page_size, &cpu_buf->buf,
+				     &cpu_buf->buf_size,
+				     perf_buffer__process_record, cpu_buf);
 	if (ret != LIBBPF_PERF_EVENT_CONT)
 		return ret;
 	return 0;
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -976,6 +976,7 @@ LIBBPF_API int perf_buffer__buffer_fd(co
 typedef enum bpf_perf_event_ret
 	(*bpf_perf_event_print_t)(struct perf_event_header *hdr,
 				  void *private_data);
+LIBBPF_DEPRECATED_SINCE(0, 8, "use perf_buffer__poll() or  perf_buffer__consume() instead")
 LIBBPF_API enum bpf_perf_event_ret
 bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
 			   void **copy_mem, size_t *copy_size,