[PATCH v2 1/3] mm/hwpoison: introduce num_poisoned_pages wrappers

[Naoya Horiguchi]

num_poisoned_pages counter will be changed outside mm/memory-failure.c by a
subsequent patch, so this patch prepares wrappers to manipulate it.

Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
---
 include/linux/swapops.h | 23 +++++++++++++++++++++++
 mm/memory-failure.c     | 30 ++++++++++++++----------------
 2 files changed, 37 insertions(+), 16 deletions(-)

diff --git mmotm-2015-08-13-15-29.orig/include/linux/swapops.h mmotm-2015-08-13-15-29/include/linux/swapops.h
index cedf3d3c373f..ec04669f2a3b 100644
--- mmotm-2015-08-13-15-29.orig/include/linux/swapops.h
+++ mmotm-2015-08-13-15-29/include/linux/swapops.h
@@ -164,6 +164,9 @@ static inline int is_write_migration_entry(swp_entry_t entry)
 #endif
 
 #ifdef CONFIG_MEMORY_FAILURE
+
+extern atomic_long_t num_poisoned_pages __read_mostly;
+
 /*
  * Support for hardware poisoned pages
  */
@@ -177,6 +180,26 @@ static inline int is_hwpoison_entry(swp_entry_t entry)
 {
 	return swp_type(entry) == SWP_HWPOISON;
 }
+
+static inline void num_poisoned_pages_inc(void)
+{
+	atomic_long_inc(&num_poisoned_pages);
+}
+
+static inline void num_poisoned_pages_dec(void)
+{
+	atomic_long_dec(&num_poisoned_pages);
+}
+
+static inline void num_poisoned_pages_add(long num)
+{
+	atomic_long_add(num, &num_poisoned_pages);
+}
+
+static inline void num_poisoned_pages_sub(long num)
+{
+	atomic_long_sub(num, &num_poisoned_pages);
+}
 #else
 
 static inline swp_entry_t make_hwpoison_entry(struct page *page)
diff --git mmotm-2015-08-13-15-29.orig/mm/memory-failure.c mmotm-2015-08-13-15-29/mm/memory-failure.c
index a3d9c3946b36..ac3056c6fe9f 100644
--- mmotm-2015-08-13-15-29.orig/mm/memory-failure.c
+++ mmotm-2015-08-13-15-29/mm/memory-failure.c
@@ -1109,7 +1109,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
 		nr_pages = 1 << compound_order(hpage);
 	else /* normal page or thp */
 		nr_pages = 1;
-	atomic_long_add(nr_pages, &num_poisoned_pages);
+	num_poisoned_pages_add(nr_pages);
 
 	/*
 	 * We need/can do nothing about count=0 pages.
@@ -1137,7 +1137,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
 			if (PageHWPoison(hpage)) {
 				if ((hwpoison_filter(p) && TestClearPageHWPoison(p))
 				    || (p != hpage && TestSetPageHWPoison(hpage))) {
-					atomic_long_sub(nr_pages, &num_poisoned_pages);
+					num_poisoned_pages_sub(nr_pages);
 					unlock_page(hpage);
 					return 0;
 				}
@@ -1161,7 +1161,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
 			else
 				pr_err("MCE: %#lx: thp split failed\n", pfn);
 			if (TestClearPageHWPoison(p))
-				atomic_long_sub(nr_pages, &num_poisoned_pages);
+				num_poisoned_pages_sub(nr_pages);
 			put_hwpoison_page(p);
 			return -EBUSY;
 		}
@@ -1221,14 +1221,14 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
 	 */
 	if (!PageHWPoison(p)) {
 		printk(KERN_ERR "MCE %#lx: just unpoisoned\n", pfn);
-		atomic_long_sub(nr_pages, &num_poisoned_pages);
+		num_poisoned_pages_sub(nr_pages);
 		unlock_page(hpage);
 		put_hwpoison_page(hpage);
 		return 0;
 	}
 	if (hwpoison_filter(p)) {
 		if (TestClearPageHWPoison(p))
-			atomic_long_sub(nr_pages, &num_poisoned_pages);
+			num_poisoned_pages_sub(nr_pages);
 		unlock_page(hpage);
 		put_hwpoison_page(hpage);
 		return 0;
@@ -1457,7 +1457,7 @@ int unpoison_memory(unsigned long pfn)
 			return 0;
 		}
 		if (TestClearPageHWPoison(p))
-			atomic_long_dec(&num_poisoned_pages);
+			num_poisoned_pages_dec();
 		pr_info("MCE: Software-unpoisoned free page %#lx\n", pfn);
 		return 0;
 	}
@@ -1471,7 +1471,7 @@ int unpoison_memory(unsigned long pfn)
 	 */
 	if (TestClearPageHWPoison(page)) {
 		pr_info("MCE: Software-unpoisoned page %#lx\n", pfn);
-		atomic_long_sub(nr_pages, &num_poisoned_pages);
+		num_poisoned_pages_sub(nr_pages);
 		freeit = 1;
 		if (PageHuge(page))
 			clear_page_hwpoison_huge_page(page);
@@ -1607,11 +1607,10 @@ static int soft_offline_huge_page(struct page *page, int flags)
 		if (PageHuge(page)) {
 			set_page_hwpoison_huge_page(hpage);
 			dequeue_hwpoisoned_huge_page(hpage);
-			atomic_long_add(1 << compound_order(hpage),
-					&num_poisoned_pages);
+			num_poisoned_pages_add(1 << compound_order(hpage));
 		} else {
 			SetPageHWPoison(page);
-			atomic_long_inc(&num_poisoned_pages);
+			num_poisoned_pages_inc();
 		}
 	}
 	return ret;
@@ -1650,7 +1649,7 @@ static int __soft_offline_page(struct page *page, int flags)
 		put_hwpoison_page(page);
 		pr_info("soft_offline: %#lx: invalidated\n", pfn);
 		SetPageHWPoison(page);
-		atomic_long_inc(&num_poisoned_pages);
+		num_poisoned_pages_inc();
 		return 0;
 	}
 
@@ -1671,7 +1670,7 @@ static int __soft_offline_page(struct page *page, int flags)
 					page_is_file_cache(page));
 		list_add(&page->lru, &pagelist);
 		if (!TestSetPageHWPoison(page))
-			atomic_long_inc(&num_poisoned_pages);
+			num_poisoned_pages_dec();
 		ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL,
 					MIGRATE_SYNC, MR_MEMORY_FAILURE);
 		if (ret) {
@@ -1687,7 +1686,7 @@ static int __soft_offline_page(struct page *page, int flags)
 			if (ret > 0)
 				ret = -EIO;
 			if (TestClearPageHWPoison(page))
-				atomic_long_dec(&num_poisoned_pages);
+				num_poisoned_pages_dec();
 		}
 	} else {
 		pr_info("soft offline: %#lx: isolation failed: %d, page count %d, type %lx\n",
@@ -1753,11 +1752,10 @@ int soft_offline_page(struct page *page, int flags)
 		if (PageHuge(page)) {
 			set_page_hwpoison_huge_page(hpage);
 			if (!dequeue_hwpoisoned_huge_page(hpage))
-				atomic_long_add(1 << compound_order(hpage),
-					&num_poisoned_pages);
+				num_poisoned_pages_add(1 << compound_order(hpage));
 		} else {
 			if (!TestSetPageHWPoison(page))
-				atomic_long_inc(&num_poisoned_pages);
+				num_poisoned_pages_inc();
 		}
 	}
 	return ret;
-- 
2.4.3
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