Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 5a3bb3b..5c626fd 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -74,13 +74,6 @@
  */
 struct pipe_buf_operations {
 	/*
-	 * This is set to 1, if the generic pipe read/write may coalesce
-	 * data into an existing buffer. If this is set to 0, a new pipe
-	 * page segment is always used for new data.
-	 */
-	int can_merge;
-
-	/*
 	 * ->confirm() verifies that the data in the pipe buffer is there
 	 * and that the contents are good. If the pages in the pipe belong
 	 * to a file system, we may need to wait for IO completion in this
@@ -108,18 +101,20 @@
 	/*
 	 * Get a reference to the pipe buffer.
 	 */
-	void (*get)(struct pipe_inode_info *, struct pipe_buffer *);
+	bool (*get)(struct pipe_inode_info *, struct pipe_buffer *);
 };
 
 /**
  * pipe_buf_get - get a reference to a pipe_buffer
  * @pipe:	the pipe that the buffer belongs to
  * @buf:	the buffer to get a reference to
+ *
+ * Return: %true if the reference was successfully obtained.
  */
-static inline void pipe_buf_get(struct pipe_inode_info *pipe,
+static inline __must_check bool pipe_buf_get(struct pipe_inode_info *pipe,
 				struct pipe_buffer *buf)
 {
-	buf->ops->get(pipe, buf);
+	return buf->ops->get(pipe, buf);
 }
 
 /**
@@ -178,10 +173,12 @@
 void free_pipe_info(struct pipe_inode_info *);
 
 /* Generic pipe buffer ops functions */
-void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);
+bool generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);
 int generic_pipe_buf_confirm(struct pipe_inode_info *, struct pipe_buffer *);
 int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *);
+int generic_pipe_buf_nosteal(struct pipe_inode_info *, struct pipe_buffer *);
 void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *);
+void pipe_buf_mark_unmergeable(struct pipe_buffer *buf);
 
 extern const struct pipe_buf_operations nosteal_pipe_buf_ops;