btrfs: Return number of compressed extents directly in compress_file_range

compress_file_range returns a void, yet uses a function parameter as a
return value. Make that more idiomatic by simply returning the number
of compressed extents directly. Also track such extents in more aptly
named variables. No functional changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/inode.c

@@ -462,8 +462,7 @@ static inline void inode_should_defrag(struct btrfs_inode *inode,
  * are written in the same order that the flusher thread sent them
  * down.
  */
-static noinline void compress_file_range(struct async_chunk *async_chunk,
-					 int *num_added)
+static noinline int compress_file_range(struct async_chunk *async_chunk)
 {
 	struct inode *inode = async_chunk->inode;
 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
@@ -479,6 +478,7 @@ static noinline void compress_file_range(struct async_chunk *async_chunk,
 	int i;
 	int will_compress;
 	int compress_type = fs_info->compress_type;
+	int compressed_extents = 0;
 	int redirty = 0;
 
 	inode_should_defrag(BTRFS_I(inode), start, end, end - start + 1,
@@ -641,7 +641,7 @@ static noinline void compress_file_range(struct async_chunk *async_chunk,
 		 */
 		total_in = ALIGN(total_in, PAGE_SIZE);
 		if (total_compressed + blocksize <= total_in) {
-			*num_added += 1;
+			compressed_extents++;
 
 			/*
 			 * The async work queues will take care of doing actual
@@ -658,7 +658,7 @@ static noinline void compress_file_range(struct async_chunk *async_chunk,
 				cond_resched();
 				goto again;
 			}
-			return;
+			return compressed_extents;
 		}
 	}
 	if (pages) {
@@ -697,9 +697,9 @@ static noinline void compress_file_range(struct async_chunk *async_chunk,
 		extent_range_redirty_for_io(inode, start, end);
 	add_async_extent(async_chunk, start, end - start + 1, 0, NULL, 0,
 			 BTRFS_COMPRESS_NONE);
-	*num_added += 1;
+	compressed_extents++;
 
-	return;
+	return compressed_extents;
 
 free_pages_out:
 	for (i = 0; i < nr_pages; i++) {
@@ -707,6 +707,8 @@ static noinline void compress_file_range(struct async_chunk *async_chunk,
 		put_page(pages[i]);
 	}
 	kfree(pages);
+
+	return 0;
 }
 
 static void free_async_extent_pages(struct async_extent *async_extent)
@@ -1144,12 +1146,12 @@ static noinline int cow_file_range(struct inode *inode,
 static noinline void async_cow_start(struct btrfs_work *work)
 {
 	struct async_chunk *async_chunk;
-	int num_added = 0;
+	int compressed_extents;
 
 	async_chunk = container_of(work, struct async_chunk, work);
 
-	compress_file_range(async_chunk, &num_added);
-	if (num_added == 0) {
+	compressed_extents = compress_file_range(async_chunk);
+	if (compressed_extents == 0) {
 		btrfs_add_delayed_iput(async_chunk->inode);
 		async_chunk->inode = NULL;
 	}