mm: page_alloc: split out FAIL_PAGE_ALLOC

... to a single file to reduce a bit of page_alloc.c.

Link: https://lkml.kernel.org/r/20230516063821.121844-8-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/fault-inject.h

@@ -93,6 +93,15 @@ struct kmem_cache;
 
 bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order);
 
+#ifdef CONFIG_FAIL_PAGE_ALLOC
+bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order);
+#else
+static inline bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
+{
+	return false;
+}
+#endif /* CONFIG_FAIL_PAGE_ALLOC */
+
 int should_failslab(struct kmem_cache *s, gfp_t gfpflags);
 #ifdef CONFIG_FAILSLAB
 extern bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags);

mm/Makefile

@@ -89,6 +89,7 @@ obj-$(CONFIG_KASAN)	+= kasan/
 obj-$(CONFIG_KFENCE) += kfence/
 obj-$(CONFIG_KMSAN)	+= kmsan/
 obj-$(CONFIG_FAILSLAB) += failslab.o
+obj-$(CONFIG_FAIL_PAGE_ALLOC) += fail_page_alloc.o
 obj-$(CONFIG_MEMTEST)		+= memtest.o
 obj-$(CONFIG_MIGRATION) += migrate.o
 obj-$(CONFIG_NUMA) += memory-tiers.o

mm/fail_page_alloc.c

@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/fault-inject.h>
+#include <linux/mm.h>
+
+static struct {
+	struct fault_attr attr;
+
+	bool ignore_gfp_highmem;
+	bool ignore_gfp_reclaim;
+	u32 min_order;
+} fail_page_alloc = {
+	.attr = FAULT_ATTR_INITIALIZER,
+	.ignore_gfp_reclaim = true,
+	.ignore_gfp_highmem = true,
+	.min_order = 1,
+};
+
+static int __init setup_fail_page_alloc(char *str)
+{
+	return setup_fault_attr(&fail_page_alloc.attr, str);
+}
+__setup("fail_page_alloc=", setup_fail_page_alloc);
+
+bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
+{
+	int flags = 0;
+
+	if (order < fail_page_alloc.min_order)
+		return false;
+	if (gfp_mask & __GFP_NOFAIL)
+		return false;
+	if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
+		return false;
+	if (fail_page_alloc.ignore_gfp_reclaim &&
+			(gfp_mask & __GFP_DIRECT_RECLAIM))
+		return false;
+
+	/* See comment in __should_failslab() */
+	if (gfp_mask & __GFP_NOWARN)
+		flags |= FAULT_NOWARN;
+
+	return should_fail_ex(&fail_page_alloc.attr, 1 << order, flags);
+}
+
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+
+static int __init fail_page_alloc_debugfs(void)
+{
+	umode_t mode = S_IFREG | 0600;
+	struct dentry *dir;
+
+	dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
+					&fail_page_alloc.attr);
+
+	debugfs_create_bool("ignore-gfp-wait", mode, dir,
+			    &fail_page_alloc.ignore_gfp_reclaim);
+	debugfs_create_bool("ignore-gfp-highmem", mode, dir,
+			    &fail_page_alloc.ignore_gfp_highmem);
+	debugfs_create_u32("min-order", mode, dir, &fail_page_alloc.min_order);
+
+	return 0;
+}
+
+late_initcall(fail_page_alloc_debugfs);
+
+#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */

mm/page_alloc.c

@@ -2994,80 +2994,6 @@ out:
 	return page;
 }
 
-#ifdef CONFIG_FAIL_PAGE_ALLOC
-
-static struct {
-	struct fault_attr attr;
-
-	bool ignore_gfp_highmem;
-	bool ignore_gfp_reclaim;
-	u32 min_order;
-} fail_page_alloc = {
-	.attr = FAULT_ATTR_INITIALIZER,
-	.ignore_gfp_reclaim = true,
-	.ignore_gfp_highmem = true,
-	.min_order = 1,
-};
-
-static int __init setup_fail_page_alloc(char *str)
-{
-	return setup_fault_attr(&fail_page_alloc.attr, str);
-}
-__setup("fail_page_alloc=", setup_fail_page_alloc);
-
-static bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
-{
-	int flags = 0;
-
-	if (order < fail_page_alloc.min_order)
-		return false;
-	if (gfp_mask & __GFP_NOFAIL)
-		return false;
-	if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
-		return false;
-	if (fail_page_alloc.ignore_gfp_reclaim &&
-			(gfp_mask & __GFP_DIRECT_RECLAIM))
-		return false;
-
-	/* See comment in __should_failslab() */
-	if (gfp_mask & __GFP_NOWARN)
-		flags |= FAULT_NOWARN;
-
-	return should_fail_ex(&fail_page_alloc.attr, 1 << order, flags);
-}
-
-#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
-
-static int __init fail_page_alloc_debugfs(void)
-{
-	umode_t mode = S_IFREG | 0600;
-	struct dentry *dir;
-
-	dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
-					&fail_page_alloc.attr);
-
-	debugfs_create_bool("ignore-gfp-wait", mode, dir,
-			    &fail_page_alloc.ignore_gfp_reclaim);
-	debugfs_create_bool("ignore-gfp-highmem", mode, dir,
-			    &fail_page_alloc.ignore_gfp_highmem);
-	debugfs_create_u32("min-order", mode, dir, &fail_page_alloc.min_order);
-
-	return 0;
-}
-
-late_initcall(fail_page_alloc_debugfs);
-
-#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
-
-#else /* CONFIG_FAIL_PAGE_ALLOC */
-
-static inline bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
-{
-	return false;
-}
-
-#endif /* CONFIG_FAIL_PAGE_ALLOC */
-
 noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
 {
 	return __should_fail_alloc_page(gfp_mask, order);