btrfs: Convert page cache to XArray

Signed-off-by: Matthew Wilcox <willy@infradead.org>
Acked-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index fd25e12..a65d144 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -437,9 +437,7 @@ static noinline int add_ra_bio_pages(struct inode *inode,
 		if (pg_index > end_index)
 			break;
 
-		rcu_read_lock();
-		page = radix_tree_lookup(&mapping->i_pages, pg_index);
-		rcu_read_unlock();
+		page = xa_load(&mapping->i_pages, pg_index);
 		if (page && !xa_is_value(page)) {
 			misses++;
 			if (misses > 4)