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/20210416231531.2521383-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/debug.c b/mm/debug.c
index 84cdcd0..e73fe0a 100644 (file)
--- 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 @@ 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);