diff mbox series

[v2,02/34] kasan, page_alloc: move tag_clear_highpage out of kernel_init_free_pages

Message ID 2ace94811bd1ce8c87519bf55bcc163c2a78d3cd.1638825394.git.andreyknvl@google.com (mailing list archive)
State New
Headers show
Series kasan, vmalloc, arm64: add vmalloc tagging support for SW/HW_TAGS | expand

Commit Message

andrey.konovalov@linux.dev Dec. 6, 2021, 9:31 p.m. UTC 
From: Andrey Konovalov <andreyknvl@google.com>

Currently, kernel_init_free_pages() serves two purposes: it either only
zeroes memory or zeroes both memory and memory tags via a different
code path. As this function has only two callers, each using only one
code path, this behaviour is confusing.

This patch pulls the code that zeroes both memory and tags out of
kernel_init_free_pages().

As a result of this change, the code in free_pages_prepare() starts to
look complicated, but this is improved in the few following patches.
Those improvements are not integrated into this patch to make diffs
easier to read.

This patch does no functional changes.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
---
 mm/page_alloc.c | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)
diff mbox series

Patch

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c99566a3b67e..3589333b5b77 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1269,16 +1269,10 @@  static inline bool should_skip_kasan_poison(struct page *page, fpi_t fpi_flags)
 	       PageSkipKASanPoison(page);
 }
 
-static void kernel_init_free_pages(struct page *page, int numpages, bool zero_tags)
+static void kernel_init_free_pages(struct page *page, int numpages)
 {
 	int i;
 
-	if (zero_tags) {
-		for (i = 0; i < numpages; i++)
-			tag_clear_highpage(page + i);
-		return;
-	}
-
 	/* s390's use of memset() could override KASAN redzones. */
 	kasan_disable_current();
 	for (i = 0; i < numpages; i++) {
@@ -1372,7 +1366,7 @@  static __always_inline bool free_pages_prepare(struct page *page,
 		bool init = want_init_on_free();
 
 		if (init)
-			kernel_init_free_pages(page, 1 << order, false);
+			kernel_init_free_pages(page, 1 << order);
 		if (!skip_kasan_poison)
 			kasan_poison_pages(page, order, init);
 	}
@@ -2415,9 +2409,17 @@  inline void post_alloc_hook(struct page *page, unsigned int order,
 		bool init = !want_init_on_free() && want_init_on_alloc(gfp_flags);
 
 		kasan_unpoison_pages(page, order, init);
-		if (init)
-			kernel_init_free_pages(page, 1 << order,
-					       gfp_flags & __GFP_ZEROTAGS);
+
+		if (init) {
+			if (gfp_flags & __GFP_ZEROTAGS) {
+				int i;
+
+				for (i = 0; i < 1 << order; i++)
+					tag_clear_highpage(page + i);
+			} else {
+				kernel_init_free_pages(page, 1 << order);
+			}
+		}
 	}
 
 	set_page_owner(page, order, gfp_flags);