f2fs: rework fault injection handling to avoid a warning

When CONFIG_F2FS_FAULT_INJECTION is disabled, we get a warning about an
unused label:

fs/f2fs/segment.c: In function '__submit_discard_cmd':
fs/f2fs/segment.c:1059:1: error: label 'submit' defined but not used [-Werror=unused-label]

This could be fixed by adding another #ifdef around it, but the more
reliable way of doing this seems to be to remove the other #ifdefs
where that is easily possible.

By defining time_to_inject() as a trivial stub, most of the checks for
CONFIG_F2FS_FAULT_INJECTION can go away. This also leads to nicer
formatting of the code.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index b04bda8..ccd4acf 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -43,7 +43,6 @@
 	} while (0)
 #endif
 
-#ifdef CONFIG_F2FS_FAULT_INJECTION
 enum {
 	FAULT_KMALLOC,
 	FAULT_KVMALLOC,
@@ -62,6 +61,7 @@
 	FAULT_MAX,
 };
 
+#ifdef CONFIG_F2FS_FAULT_INJECTION
 #define F2FS_ALL_FAULT_TYPE		((1 << FAULT_MAX) - 1)
 
 struct f2fs_fault_info {
@@ -1323,6 +1323,12 @@
 	}
 	return false;
 }
+#else
+#define f2fs_show_injection_info(type) do { } while (0)
+static inline bool time_to_inject(struct f2fs_sb_info *sbi, int type)
+{
+	return false;
+}
 #endif
 
 /* For write statistics. Suppose sector size is 512 bytes,
@@ -1675,13 +1681,12 @@
 	if (ret)
 		return ret;
 
-#ifdef CONFIG_F2FS_FAULT_INJECTION
 	if (time_to_inject(sbi, FAULT_BLOCK)) {
 		f2fs_show_injection_info(FAULT_BLOCK);
 		release = *count;
 		goto enospc;
 	}
-#endif
+
 	/*
 	 * let's increase this in prior to actual block count change in order
 	 * for f2fs_sync_file to avoid data races when deciding checkpoint.
@@ -1890,12 +1895,10 @@
 			return ret;
 	}
 
-#ifdef CONFIG_F2FS_FAULT_INJECTION
 	if (time_to_inject(sbi, FAULT_BLOCK)) {
 		f2fs_show_injection_info(FAULT_BLOCK);
 		goto enospc;
 	}
-#endif
 
 	spin_lock(&sbi->stat_lock);
 
@@ -1980,22 +1983,23 @@
 static inline struct page *f2fs_grab_cache_page(struct address_space *mapping,
 						pgoff_t index, bool for_write)
 {
-#ifdef CONFIG_F2FS_FAULT_INJECTION
 	struct page *page;
 
-	if (!for_write)
-		page = find_get_page_flags(mapping, index,
-						FGP_LOCK | FGP_ACCESSED);
-	else
-		page = find_lock_page(mapping, index);
-	if (page)
-		return page;
+	if (IS_ENABLED(CONFIG_F2FS_FAULT_INJECTION)) {
+		if (!for_write)
+			page = find_get_page_flags(mapping, index,
+							FGP_LOCK | FGP_ACCESSED);
+		else
+			page = find_lock_page(mapping, index);
+		if (page)
+			return page;
 
-	if (time_to_inject(F2FS_M_SB(mapping), FAULT_PAGE_ALLOC)) {
-		f2fs_show_injection_info(FAULT_PAGE_ALLOC);
-		return NULL;
+		if (time_to_inject(F2FS_M_SB(mapping), FAULT_PAGE_ALLOC)) {
+			f2fs_show_injection_info(FAULT_PAGE_ALLOC);
+			return NULL;
+		}
 	}
-#endif
+
 	if (!for_write)
 		return grab_cache_page(mapping, index);
 	return grab_cache_page_write_begin(mapping, index, AOP_FLAG_NOFS);
@@ -2005,12 +2009,11 @@
 				struct address_space *mapping, pgoff_t index,
 				int fgp_flags, gfp_t gfp_mask)
 {
-#ifdef CONFIG_F2FS_FAULT_INJECTION
 	if (time_to_inject(F2FS_M_SB(mapping), FAULT_PAGE_GET)) {
 		f2fs_show_injection_info(FAULT_PAGE_GET);
 		return NULL;
 	}
-#endif
+
 	return pagecache_get_page(mapping, index, fgp_flags, gfp_mask);
 }
 
@@ -2075,12 +2078,11 @@
 			bio = bio_alloc(GFP_NOIO | __GFP_NOFAIL, npages);
 		return bio;
 	}
-#ifdef CONFIG_F2FS_FAULT_INJECTION
 	if (time_to_inject(sbi, FAULT_ALLOC_BIO)) {
 		f2fs_show_injection_info(FAULT_ALLOC_BIO);
 		return NULL;
 	}
-#endif
+
 	return bio_alloc(GFP_KERNEL, npages);
 }
 
@@ -2615,12 +2617,11 @@
 static inline void *f2fs_kmalloc(struct f2fs_sb_info *sbi,
 					size_t size, gfp_t flags)
 {
-#ifdef CONFIG_F2FS_FAULT_INJECTION
 	if (time_to_inject(sbi, FAULT_KMALLOC)) {
 		f2fs_show_injection_info(FAULT_KMALLOC);
 		return NULL;
 	}
-#endif
+
 	return kmalloc(size, flags);
 }
 
@@ -2663,12 +2664,11 @@
 static inline void *f2fs_kvmalloc(struct f2fs_sb_info *sbi,
 					size_t size, gfp_t flags)
 {
-#ifdef CONFIG_F2FS_FAULT_INJECTION
 	if (time_to_inject(sbi, FAULT_KVMALLOC)) {
 		f2fs_show_injection_info(FAULT_KVMALLOC);
 		return NULL;
 	}
-#endif
+
 	return kvmalloc(size, flags);
 }