From: Filipe Manana <fdmanana@suse.com>
Date: Mon, 19 Sep 2022 14:06:37 +0000 (+0100)
Subject: btrfs: remove unnecessary NULL pointer checks when searching extent maps
X-Git-Tag: v6.6.17~6129^2~47
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=08f088dd63abebb2cce5510cedd33a36bd0cf490;p=platform%2Fkernel%2Flinux-rpi.git

btrfs: remove unnecessary NULL pointer checks when searching extent maps

The previous and next pointer arguments passed to __tree_search() are
never NULL as the only caller of this function, __lookup_extent_mapping(),
always passes the address of two on stack pointers. So remove the NULL
checks and add assertions to verify the pointers.

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

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index f1616aa..774fee9 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -150,6 +150,9 @@ static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
 	struct extent_map *entry;
 	struct extent_map *prev_entry = NULL;
 
+	ASSERT(prev_ret);
+	ASSERT(next_ret);
+
 	while (n) {
 		entry = rb_entry(n, struct extent_map, rb_node);
 		prev = n;
@@ -163,24 +166,21 @@ static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
 			return n;
 	}
 
-	if (prev_ret) {
-		orig_prev = prev;
-		while (prev && offset >= extent_map_end(prev_entry)) {
-			prev = rb_next(prev);
-			prev_entry = rb_entry(prev, struct extent_map, rb_node);
-		}
-		*prev_ret = prev;
-		prev = orig_prev;
+	orig_prev = prev;
+	while (prev && offset >= extent_map_end(prev_entry)) {
+		prev = rb_next(prev);
+		prev_entry = rb_entry(prev, struct extent_map, rb_node);
 	}
+	*prev_ret = prev;
+	prev = orig_prev;
 
-	if (next_ret) {
+	prev_entry = rb_entry(prev, struct extent_map, rb_node);
+	while (prev && offset < prev_entry->start) {
+		prev = rb_prev(prev);
 		prev_entry = rb_entry(prev, struct extent_map, rb_node);
-		while (prev && offset < prev_entry->start) {
-			prev = rb_prev(prev);
-			prev_entry = rb_entry(prev, struct extent_map, rb_node);
-		}
-		*next_ret = prev;
 	}
+	*next_ret = prev;
+
 	return NULL;
 }