btrfs: eliminate extra call when doing binary search on extent buffer

The function btrfs_bin_search() is just a wrapper around the function
generic_bin_search(), which passes the same arguments plus a default
low slot with a value of 0. This adds an unnecessary extra function
call, since btrfs_bin_search() is not static. So improve on this by
making btrfs_bin_search() an inline function that calls
generic_bin_search(), renaming the later to btrfs_generic_bin_search()
and exporting it.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: fdmanana

fs/btrfs/ctree.c

@@ -863,8 +863,8 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
  * Slot may point to the total number of items (i.e. one position beyond the last
  * key) if the key is bigger than the last key in the extent buffer.
  */
-static noinline int generic_bin_search(struct extent_buffer *eb, int low,
-				       const struct btrfs_key *key, int *slot)
+int btrfs_generic_bin_search(struct extent_buffer *eb, int low,
+			     const struct btrfs_key *key, int *slot)
 {
 	unsigned long p;
 	int item_size;
@@ -925,16 +925,6 @@ static noinline int generic_bin_search(struct extent_buffer *eb, int low,
 	return 1;
 }
 
-/*
- * Simple binary search on an extent buffer. Works for both leaves and nodes, and
- * always searches over the whole range of keys (slot 0 to slot 'nritems - 1').
- */
-int btrfs_bin_search(struct extent_buffer *eb, const struct btrfs_key *key,
-		     int *slot)
-{
-	return generic_bin_search(eb, 0, key, slot);
-}
-
 static void root_add_used(struct btrfs_root *root, u32 size)
 {
 	spin_lock(&root->accounting_lock);
@@ -1869,7 +1859,7 @@ static inline int search_for_key_slot(struct extent_buffer *eb,
 		return 0;
 	}
 
-	return generic_bin_search(eb, search_low_slot, key, slot);
+	return btrfs_generic_bin_search(eb, search_low_slot, key, slot);
 }
 
 static int search_leaf(struct btrfs_trans_handle *trans,

fs/btrfs/ctree.h

@@ -507,6 +507,21 @@ int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range);
 /* ctree.c */
 int __init btrfs_ctree_init(void);
 void __cold btrfs_ctree_exit(void);
+
+int btrfs_generic_bin_search(struct extent_buffer *eb, int low,
+			     const struct btrfs_key *key, int *slot);
+
+/*
+ * Simple binary search on an extent buffer. Works for both leaves and nodes, and
+ * always searches over the whole range of keys (slot 0 to slot 'nritems - 1').
+ */
+static inline int btrfs_bin_search(struct extent_buffer *eb,
+				   const struct btrfs_key *key,
+				   int *slot)
+{
+	return btrfs_generic_bin_search(eb, 0, key, slot);
+}
+
 int btrfs_bin_search(struct extent_buffer *eb, const struct btrfs_key *key,
 		     int *slot);
 int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2);