Re: [PATCH 3/8] 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().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <redacted>
Reviewed-by: Vlastimil Babka <redacted>
Reviewed-by: Anshuman Khandual <redacted>
---
  mm/debug.c | 25 +++++++------------------
  1 file changed, 7 insertions(+), 18 deletions(-)

diff --git a/mm/debug.c b/mm/debug.c
index 84cdcd0f7bd3..e73fe0a8ec3d 100644
--- a/mm/debug.c
+++ b/mm/debug.c

@@ -42,11 +42,10 @@ const struct trace_print_flags vmaflag_names[] = {
  	{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 *page, const char *reason)
  	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 @@ static void __dump_page(struct page *page, const char *reason)
  
  	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 @@ static void __dump_page(struct page *page, const char *reason)
  		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);