perf/ring_buffer: Matching the memory allocate and free, in rb_alloc()

Currently perf_mmap_alloc_page() is used to allocate memory in
rb_alloc(), but using free_page() to free memory in the failure path.

It's better to use perf_mmap_free_page() instead.

Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <jolsa@redhat.co>
Cc: <acme@kernel.org>
Cc: <mingo@redhat.com>
Cc: <mark.rutland@arm.com>
Cc: <namhyung@kernel.org>
Cc: <alexander.shishkin@linux.intel.com>
Link: https://lkml.kernel.org/r/575c7e8c-90c7-4e3a-b41d-f894d8cdbd7f@huawei.com

kernel/events/ring_buffer.c

@@ -754,6 +754,14 @@ static void *perf_mmap_alloc_page(int cpu)
 	return page_address(page);
 }
 
+static void perf_mmap_free_page(void *addr)
+{
+	struct page *page = virt_to_page(addr);
+
+	page->mapping = NULL;
+	__free_page(page);
+}
+
 struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
 {
 	struct ring_buffer *rb;
@@ -788,9 +796,9 @@ struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
 
 fail_data_pages:
 	for (i--; i >= 0; i--)
-		free_page((unsigned long)rb->data_pages[i]);
+		perf_mmap_free_page(rb->data_pages[i]);
 
-	free_page((unsigned long)rb->user_page);
+	perf_mmap_free_page(rb->user_page);
 
 fail_user_page:
 	kfree(rb);
@@ -799,14 +807,6 @@ fail:
 	return NULL;
 }
 
-static void perf_mmap_free_page(void *addr)
-{
-	struct page *page = virt_to_page(addr);
-
-	page->mapping = NULL;
-	__free_page(page);
-}
-
 void rb_free(struct ring_buffer *rb)
 {
 	int i;