lift sb_start_write out of ->splice_write()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/splice.c

@@ -1000,8 +1000,6 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 	};
 	ssize_t ret;
 
-	sb_start_write(inode->i_sb);
-
 	pipe_lock(pipe);
 
 	splice_from_pipe_begin(&sd);
@@ -1037,7 +1035,6 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 			*ppos += ret;
 		balance_dirty_pages_ratelimited(mapping);
 	}
-	sb_end_write(inode->i_sb);
 
 	return ret;
 }
@@ -1064,9 +1061,7 @@ static ssize_t default_file_splice_write(struct pipe_inode_info *pipe,
 {
 	ssize_t ret;
 
-	file_start_write(out);
 	ret = splice_from_pipe(pipe, out, ppos, len, flags, write_pipe_buf);
-	file_end_write(out);
 	if (ret > 0)
 		*ppos += ret;
 
@@ -1119,7 +1114,10 @@ static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
 	else
 		splice_write = default_file_splice_write;
 
-	return splice_write(pipe, out, ppos, len, flags);
+	file_start_write(out);
+	ret = splice_write(pipe, out, ppos, len, flags);
+	file_end_write(out);
+	return ret;
 }
 
 /*