btrfs: simplify debug print helpers without enabled printk

The btrfs_debug() helpers depend on various config options. In case of
"no_printk" we don't need to define a special helper that in the end
does nothing but validates the parameters. As the default build config
is to validate the parameters we can simplify it to let the debug
helpers expand to nothing and remove btrfs_no_printk_in_rcu().

To avoid warnings use fs_info and inline one variable in
extent_from_logical().

Reviewed-by: Daniel Vacek <neelx@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: kdave

fs/btrfs/backref.c

@@ -2201,7 +2201,6 @@ int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
 	int ret;
 	u64 flags;
 	u64 size = 0;
-	u32 item_size;
 	const struct extent_buffer *eb;
 	struct btrfs_extent_item *ei;
 	struct btrfs_key key;
@@ -2244,15 +2243,14 @@ int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
 	}
 
 	eb = path->nodes[0];
-	item_size = btrfs_item_size(eb, path->slots[0]);
 
 	ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
 	flags = btrfs_extent_flags(eb, ei);
 
 	btrfs_debug(fs_info,
 		"logical %llu is at position %llu within the extent (%llu EXTENT_ITEM %llu) flags %#llx size %u",
 		 logical, logical - found_key->objectid, found_key->objectid,
-		 found_key->offset, flags, item_size);
+		 found_key->offset, flags, btrfs_item_size(eb, path->slots[0]));
 
 	WARN_ON(!flags_ret);
 	if (flags_ret) {

fs/btrfs/messages.h

@@ -74,10 +74,9 @@ void _btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...);
 #define btrfs_debug_rl(fs_info, fmt, args...) \
 	btrfs_printk_rl_in_rcu(fs_info, KERN_DEBUG fmt, ##args)
 #else
-#define btrfs_debug(fs_info, fmt, args...) \
-	btrfs_no_printk_in_rcu(fs_info, KERN_DEBUG fmt, ##args)
-#define btrfs_debug_rl(fs_info, fmt, args...) \
-	btrfs_no_printk_in_rcu(fs_info, KERN_DEBUG fmt, ##args)
+/* When printk() is no_printk(), expand to no-op. */
+#define btrfs_debug(fs_info, fmt, args...)	do { (void)(fs_info); } while(0)
+#define btrfs_debug_rl(fs_info, fmt, args...)	do { (void)(fs_info); } while(0)
 #endif
 
 #define btrfs_printk_in_rcu(fs_info, fmt, args...)	\
@@ -87,13 +86,6 @@ do {							\
 	rcu_read_unlock();				\
 } while (0)
 
-#define btrfs_no_printk_in_rcu(fs_info, fmt, args...)	\
-do {							\
-	rcu_read_lock();				\
-	btrfs_no_printk(fs_info, fmt, ##args);		\
-	rcu_read_unlock();				\
-} while (0)
-
 #define btrfs_printk_ratelimited(fs_info, fmt, args...)		\
 do {								\
 	static DEFINE_RATELIMIT_STATE(_rs,			\