[PATCH v2 37/39] codetag: debug: mark codetags for reserved pages as empty

[Suren Baghdasaryan <surenb@google.com>]

To avoid debug warnings while freeing reserved pages which were not
allocated with usual allocators, mark their codetags as empty before
freeing.
Maybe we can annotate reserved pages correctly and avoid this?

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 include/linux/alloc_tag.h   | 2 ++
 include/linux/mm.h          | 8 ++++++++
 include/linux/pgalloc_tag.h | 2 ++
 3 files changed, 12 insertions(+)

diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h
index 1f3207097b03..102caf62c2a9 100644
--- a/include/linux/alloc_tag.h
+++ b/include/linux/alloc_tag.h
@@ -95,6 +95,7 @@ static inline void set_codetag_empty(union codetag_ref *ref)
 #else /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */
 
 static inline bool is_codetag_empty(union codetag_ref *ref) { return false; }
+static inline void set_codetag_empty(union codetag_ref *ref) {}
 
 #endif /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */
 
@@ -155,6 +156,7 @@ static inline void alloc_tag_sub(union codetag_ref *ref, size_t bytes) {}
 static inline void alloc_tag_sub_noalloc(union codetag_ref *ref, size_t bytes) {}
 static inline void alloc_tag_add(union codetag_ref *ref, struct alloc_tag *tag,
 				 size_t bytes) {}
+static inline void set_codetag_empty(union codetag_ref *ref) {}
 
 #endif
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index bf5d0b1b16f4..310129414833 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -5,6 +5,7 @@
 #include <linux/errno.h>
 #include <linux/mmdebug.h>
 #include <linux/gfp.h>
+#include <linux/pgalloc_tag.h>
 #include <linux/bug.h>
 #include <linux/list.h>
 #include <linux/mmzone.h>
@@ -3077,6 +3078,13 @@ extern void reserve_bootmem_region(phys_addr_t start,
 /* Free the reserved page into the buddy system, so it gets managed. */
 static inline void free_reserved_page(struct page *page)
 {
+	union codetag_ref *ref;
+
+	ref = get_page_tag_ref(page);
+	if (ref) {
+		set_codetag_empty(ref);
+		put_page_tag_ref(ref);
+	}
 	ClearPageReserved(page);
 	init_page_count(page);
 	__free_page(page);
diff --git a/include/linux/pgalloc_tag.h b/include/linux/pgalloc_tag.h
index 0174aff5e871..ae9b0f359264 100644
--- a/include/linux/pgalloc_tag.h
+++ b/include/linux/pgalloc_tag.h
@@ -93,6 +93,8 @@ static inline void pgalloc_tag_split(struct page *page, unsigned int nr)
 
 #else /* CONFIG_MEM_ALLOC_PROFILING */
 
+static inline union codetag_ref *get_page_tag_ref(struct page *page) { return NULL; }
+static inline void put_page_tag_ref(union codetag_ref *ref) {}
 static inline void pgalloc_tag_add(struct page *page, struct task_struct *task,
 				   unsigned int order) {}
 static inline void pgalloc_tag_sub(struct page *page, unsigned int order) {}
-- 
2.42.0.758.gaed0368e0e-goog