Merge branch 'akpm' (patches from Andrew)

Merge second patch-bomb from Andrew Morton:

 - more MM stuff:

    - Kirill's page-flags rework

    - Kirill's now-allegedly-fixed THP rework

    - MADV_FREE implementation

    - DAX feature work (msync/fsync).  This isn't quite complete but DAX
      is new and it's good enough and the guys have a handle on what
      needs to be done - I expect this to be wrapped in the next week or
      two.

  - some vsprintf maintenance work

  - various other misc bits

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (145 commits)
  printk: change recursion_bug type to bool
  lib/vsprintf: factor out %pN[F] handler as netdev_bits()
  lib/vsprintf: refactor duplicate code to special_hex_number()
  printk-formats.txt: remove unimplemented %pT
  printk: help pr_debug and pr_devel to optimize out arguments
  lib/test_printf.c: test dentry printing
  lib/test_printf.c: add test for large bitmaps
  lib/test_printf.c: account for kvasprintf tests
  lib/test_printf.c: add a few number() tests
  lib/test_printf.c: test precision quirks
  lib/test_printf.c: check for out-of-bound writes
  lib/test_printf.c: don't BUG
  lib/kasprintf.c: add sanity check to kvasprintf
  lib/vsprintf.c: warn about too large precisions and field widths
  lib/vsprintf.c: help gcc make number() smaller
  lib/vsprintf.c: expand field_width to 24 bits
  lib/vsprintf.c: eliminate potential race in string()
  lib/vsprintf.c: move string() below widen_string()
  lib/vsprintf.c: pull out padding code from dentry_name()
  printk: do cond_resched() between lines while outputting to consoles
  ...

1 files changed, 58 insertions, 67 deletions

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 8424b64711ac..ac595e7a3a95 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -882,15 +882,7 @@ int get_hwpoison_page(struct page *page)
 {
 	struct page *head = compound_head(page);
 
-	if (PageHuge(head))
-		return get_page_unless_zero(head);
-
-	/*
-	 * Thp tail page has special refcounting rule (refcount of tail pages
-	 * is stored in ->_mapcount,) so we can't call get_page_unless_zero()
-	 * directly for tail pages.
-	 */
-	if (PageTransHuge(head)) {
+	if (!PageHuge(head) && PageTransHuge(head)) {
 		/*
 		 * Non anonymous thp exists only in allocation/free time. We
 		 * can't handle such a case correctly, so let's give it up.
@@ -902,41 +894,12 @@ int get_hwpoison_page(struct page *page)
 				page_to_pfn(page));
 			return 0;
 		}
-
-		if (get_page_unless_zero(head)) {
-			if (PageTail(page))
-				get_page(page);
-			return 1;
-		} else {
-			return 0;
-		}
 	}
 
-	return get_page_unless_zero(page);
+	return get_page_unless_zero(head);
 }
 EXPORT_SYMBOL_GPL(get_hwpoison_page);
 
-/**
- * put_hwpoison_page() - Put refcount for memory error handling:
- * @page:	raw error page (hit by memory error)
- */
-void put_hwpoison_page(struct page *page)
-{
-	struct page *head = compound_head(page);
-
-	if (PageHuge(head)) {
-		put_page(head);
-		return;
-	}
-
-	if (PageTransHuge(head))
-		if (page != head)
-			put_page(head);
-
-	put_page(page);
-}
-EXPORT_SYMBOL_GPL(put_hwpoison_page);
-
 /*
  * Do all that is necessary to remove user space mappings. Unmap
  * the pages and send SIGBUS to the processes if the data was dirty.
@@ -1149,7 +1112,9 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
 	}
 
 	if (!PageHuge(p) && PageTransHuge(hpage)) {
+		lock_page(hpage);
 		if (!PageAnon(hpage) || unlikely(split_huge_page(hpage))) {
+			unlock_page(hpage);
 			if (!PageAnon(hpage))
 				pr_err("MCE: %#lx: non anonymous thp\n", pfn);
 			else
@@ -1159,6 +1124,9 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
 			put_hwpoison_page(p);
 			return -EBUSY;
 		}
+		unlock_page(hpage);
+		get_hwpoison_page(p);
+		put_hwpoison_page(hpage);
 		VM_BUG_ON_PAGE(!page_count(p), p);
 		hpage = compound_head(p);
 	}
@@ -1166,7 +1134,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
 	/*
 	 * We ignore non-LRU pages for good reasons.
 	 * - PG_locked is only well defined for LRU pages and a few others
-	 * - to avoid races with __set_page_locked()
+	 * - to avoid races with __SetPageLocked()
 	 * - to avoid races with __SetPageSlab*() (and more non-atomic ops)
 	 * The check (unnecessarily) ignores LRU pages being isolated and
 	 * walked by the page reclaim code, however that's not a big loss.
@@ -1572,7 +1540,7 @@ static int get_any_page(struct page *page, unsigned long pfn, int flags)
 		 * Did it turn free?
 		 */
 		ret = __get_any_page(page, pfn, 0);
-		if (!PageLRU(page)) {
+		if (ret == 1 && !PageLRU(page)) {
 			/* Drop page reference which is from __get_any_page() */
 			put_hwpoison_page(page);
 			pr_info("soft_offline: %#lx: unknown non LRU page type %lx\n",
@@ -1716,6 +1684,49 @@ static int __soft_offline_page(struct page *page, int flags)
 	return ret;
 }
 
+static int soft_offline_in_use_page(struct page *page, int flags)
+{
+	int ret;
+	struct page *hpage = compound_head(page);
+
+	if (!PageHuge(page) && PageTransHuge(hpage)) {
+		lock_page(hpage);
+		if (!PageAnon(hpage) || unlikely(split_huge_page(hpage))) {
+			unlock_page(hpage);
+			if (!PageAnon(hpage))
+				pr_info("soft offline: %#lx: non anonymous thp\n", page_to_pfn(page));
+			else
+				pr_info("soft offline: %#lx: thp split failed\n", page_to_pfn(page));
+			put_hwpoison_page(hpage);
+			return -EBUSY;
+		}
+		unlock_page(hpage);
+		get_hwpoison_page(page);
+		put_hwpoison_page(hpage);
+	}
+
+	if (PageHuge(page))
+		ret = soft_offline_huge_page(page, flags);
+	else
+		ret = __soft_offline_page(page, flags);
+
+	return ret;
+}
+
+static void soft_offline_free_page(struct page *page)
+{
+	if (PageHuge(page)) {
+		struct page *hpage = compound_head(page);
+
+		set_page_hwpoison_huge_page(hpage);
+		if (!dequeue_hwpoisoned_huge_page(hpage))
+			num_poisoned_pages_add(1 << compound_order(hpage));
+	} else {
+		if (!TestSetPageHWPoison(page))
+			num_poisoned_pages_inc();
+	}
+}
+
 /**
  * soft_offline_page - Soft offline a page.
  * @page: page to offline
@@ -1742,7 +1753,6 @@ int soft_offline_page(struct page *page, int flags)
 {
 	int ret;
 	unsigned long pfn = page_to_pfn(page);
-	struct page *hpage = compound_head(page);
 
 	if (PageHWPoison(page)) {
 		pr_info("soft offline: %#lx page already poisoned\n", pfn);
@@ -1750,34 +1760,15 @@ int soft_offline_page(struct page *page, int flags)
 			put_hwpoison_page(page);
 		return -EBUSY;
 	}
-	if (!PageHuge(page) && PageTransHuge(hpage)) {
-		if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) {
-			pr_info("soft offline: %#lx: failed to split THP\n",
-				pfn);
-			if (flags & MF_COUNT_INCREASED)
-				put_hwpoison_page(page);
-			return -EBUSY;
-		}
-	}
 
 	get_online_mems();
-
 	ret = get_any_page(page, pfn, flags);
 	put_online_mems();
-	if (ret > 0) { /* for in-use pages */
-		if (PageHuge(page))
-			ret = soft_offline_huge_page(page, flags);
-		else
-			ret = __soft_offline_page(page, flags);
-	} else if (ret == 0) { /* for free pages */
-		if (PageHuge(page)) {
-			set_page_hwpoison_huge_page(hpage);
-			if (!dequeue_hwpoisoned_huge_page(hpage))
-				num_poisoned_pages_add(1 << compound_order(hpage));
-		} else {
-			if (!TestSetPageHWPoison(page))
-				num_poisoned_pages_inc();
-		}
-	}
+
+	if (ret > 0)
+		ret = soft_offline_in_use_page(page, flags);
+	else if (ret == 0)
+		soft_offline_free_page(page);
+
 	return ret;
 }