[152/192] mm/debug: factor PagePoisoned out of __dump_page

Commit Message

Andrew Morton June 29, 2021, 2:41 a.m. UTC

From: "Matthew Wilcox (Oracle)" <[e-mail]>
Subject: mm/debug: factor PagePoisoned out of __dump_page

Move the PagePoisoned test into dump_page().  Skip the hex print for
poisoned pages -- we know they're full of ffffffff.  Move the reason
printing from __dump_page() to dump_page().

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Matthew Wilcox (Oracle) <[e-mail]>
Reviewed-by: Vlastimil Babka <[e-mail]>
Reviewed-by: Anshuman Khandual <[e-mail]>
Reviewed-by: William Kucharski <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/debug.c |   25 +++++++------------------
 1 file changed, 7 insertions(+), 18 deletions(-)

Patch

--- a/mm/debug.c~mm-debug-factor-pagepoisoned-out-of-__dump_page
+++ a/mm/debug.c
@@ -42,11 +42,10 @@  const struct trace_print_flags vmaflag_n
 	{0, NULL}
 };
 
-static void __dump_page(struct page *page, const char *reason)
+static void __dump_page(struct page *page)
 {
 	struct page *head = compound_head(page);
 	struct address_space *mapping;
-	bool page_poisoned = PagePoisoned(page);
 	bool compound = PageCompound(page);
 	/*
 	 * Accessing the pageblock without the zone lock. It could change to
@@ -58,16 +57,6 @@  static void __dump_page(struct page *pag
 	int mapcount;
 	char *type = "";
 
-	/*
-	 * If struct page is poisoned don't access Page*() functions as that
-	 * leads to recursive loop. Page*() check for poisoned pages, and calls
-	 * dump_page() when detected.
-	 */
-	if (page_poisoned) {
-		pr_warn("page:%px is uninitialized and poisoned", page);
-		goto hex_only;
-	}
-
 	if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) {
 		/*
 		 * Corrupt page, so we cannot call page_mapping. Instead, do a
@@ -173,8 +162,6 @@  out_mapping:
 
 	pr_warn("%sflags: %#lx(%pGp)%s\n", type, head->flags, &head->flags,
 		page_cma ? " CMA" : "");
-
-hex_only:
 	print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
 			sizeof(unsigned long), page,
 			sizeof(struct page), false);
@@ -182,14 +169,16 @@  hex_only:
 		print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
 			sizeof(unsigned long), head,
 			sizeof(struct page), false);
-
-	if (reason)
-		pr_warn("page dumped because: %s\n", reason);
 }
 
 void dump_page(struct page *page, const char *reason)
 {
-	__dump_page(page, reason);
+	if (PagePoisoned(page))
+		pr_warn("page:%p is uninitialized and poisoned", page);
+	else
+		__dump_page(page);
+	if (reason)
+		pr_warn("page dumped because: %s\n", reason);
 	dump_page_owner(page);
 }
 EXPORT_SYMBOL(dump_page);