[Patch v2 1/4] mm: enable dump several reasons for __dump_page()

[Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>]

This is a preparation to dump all reasons during check page.

Signed-off-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
---
 include/linux/mmdebug.h |  2 +-
 mm/debug.c              | 11 ++++++-----
 mm/page_alloc.c         |  2 +-
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index 2ad72d2c8cc5..f0a612db8bae 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -10,7 +10,7 @@ struct vm_area_struct;
 struct mm_struct;
 
 extern void dump_page(struct page *page, const char *reason);
-extern void __dump_page(struct page *page, const char *reason);
+extern void __dump_page(struct page *page, int num, const char **reason);
 void dump_vma(const struct vm_area_struct *vma);
 void dump_mm(const struct mm_struct *mm);
 
diff --git a/mm/debug.c b/mm/debug.c
index 0461df1207cb..a8ac6f951f9f 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -42,11 +42,11 @@ const struct trace_print_flags vmaflag_names[] = {
 	{0, NULL}
 };
 
-void __dump_page(struct page *page, const char *reason)
+void __dump_page(struct page *page, int num, const char **reason)
 {
 	struct address_space *mapping;
 	bool page_poisoned = PagePoisoned(page);
-	int mapcount;
+	int mapcount, i;
 
 	/*
 	 * If struct page is poisoned don't access Page*() functions as that
@@ -97,8 +97,9 @@ void __dump_page(struct page *page, const char *reason)
 			sizeof(unsigned long), page,
 			sizeof(struct page), false);
 
-	if (reason)
-		pr_warn("page dumped because: %s\n", reason);
+	pr_warn("page dumped because:\n");
+	for (i = 0; i < num; i++)
+		pr_warn("\t%s\n", reason[i]);
 
 #ifdef CONFIG_MEMCG
 	if (!page_poisoned && page->mem_cgroup)
@@ -108,7 +109,7 @@ void __dump_page(struct page *page, const char *reason)
 
 void dump_page(struct page *page, const char *reason)
 {
-	__dump_page(page, reason);
+	__dump_page(page, 1, &reason);
 	dump_page_owner(page);
 }
 EXPORT_SYMBOL(dump_page);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d047bf7d8fd4..0cf6218aaba7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -638,7 +638,7 @@ static void bad_page(struct page *page, const char *reason,
 
 	pr_alert("BUG: Bad page state in process %s  pfn:%05lx\n",
 		current->comm, page_to_pfn(page));
-	__dump_page(page, reason);
+	__dump_page(page, 1, &reason);
 	bad_flags &= page->flags;
 	if (bad_flags)
 		pr_alert("bad because of flags: %#lx(%pGp)\n",
-- 
2.17.1