Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 814643f..936b61b 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -1,7 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * kernfs.h - pseudo filesystem decoupled from vfs locking
- *
- * This file is released under the GPLv2.
  */
 
 #ifndef __LINUX_KERNFS_H
@@ -25,7 +24,10 @@
 struct vm_area_struct;
 struct super_block;
 struct file_system_type;
+struct poll_table_struct;
+struct fs_context;
 
+struct kernfs_fs_context;
 struct kernfs_open_node;
 struct kernfs_iattrs;
 
@@ -61,7 +63,7 @@
 	KERNFS_ROOT_CREATE_DEACTIVATED		= 0x0001,
 
 	/*
-	 * For regular flies, if the opener has CAP_DAC_OVERRIDE, open(2)
+	 * For regular files, if the opener has CAP_DAC_OVERRIDE, open(2)
 	 * succeeds regardless of the RW permissions.  sysfs had an extra
 	 * layer of enforcement where open(2) fails with -EACCES regardless
 	 * of CAP_DAC_OVERRIDE if the permission doesn't have the
@@ -167,7 +169,6 @@
  * kernfs_node parameter.
  */
 struct kernfs_syscall_ops {
-	int (*remount_fs)(struct kernfs_root *root, int *flags, char *data);
 	int (*show_options)(struct seq_file *sf, struct kernfs_root *root);
 
 	int (*mkdir)(struct kernfs_node *parent, const char *name,
@@ -261,6 +262,9 @@
 	ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t bytes,
 			 loff_t off);
 
+	__poll_t (*poll)(struct kernfs_open_file *of,
+			 struct poll_table_struct *pt);
+
 	int (*mmap)(struct kernfs_open_file *of, struct vm_area_struct *vma);
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
@@ -268,6 +272,18 @@
 #endif
 };
 
+/*
+ * The kernfs superblock creation/mount parameter context.
+ */
+struct kernfs_fs_context {
+	struct kernfs_root	*root;		/* Root of the hierarchy being mounted */
+	void			*ns_tag;	/* Namespace tag of the mount (or NULL) */
+	unsigned long		magic;		/* File system specific magic number */
+
+	/* The following are set/used by kernfs_mount() */
+	bool			new_sb_created;	/* Set to T if we allocated a new sb */
+};
+
 #ifdef CONFIG_KERNFS
 
 static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
@@ -350,14 +366,19 @@
 int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
 		     const char *new_name, const void *new_ns);
 int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr);
+__poll_t kernfs_generic_poll(struct kernfs_open_file *of,
+			     struct poll_table_struct *pt);
 void kernfs_notify(struct kernfs_node *kn);
 
+int kernfs_xattr_get(struct kernfs_node *kn, const char *name,
+		     void *value, size_t size);
+int kernfs_xattr_set(struct kernfs_node *kn, const char *name,
+		     const void *value, size_t size, int flags);
+
 const void *kernfs_super_ns(struct super_block *sb);
-struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
-			       struct kernfs_root *root, unsigned long magic,
-			       bool *new_sb_created, const void *ns);
+int kernfs_get_tree(struct fs_context *fc);
+void kernfs_free_fs_context(struct fs_context *fc);
 void kernfs_kill_sb(struct super_block *sb);
-struct super_block *kernfs_pin_sb(struct kernfs_root *root, const void *ns);
 
 void kernfs_init(void);
 
@@ -456,14 +477,21 @@
 
 static inline void kernfs_notify(struct kernfs_node *kn) { }
 
+static inline int kernfs_xattr_get(struct kernfs_node *kn, const char *name,
+				   void *value, size_t size)
+{ return -ENOSYS; }
+
+static inline int kernfs_xattr_set(struct kernfs_node *kn, const char *name,
+				   const void *value, size_t size, int flags)
+{ return -ENOSYS; }
+
 static inline const void *kernfs_super_ns(struct super_block *sb)
 { return NULL; }
 
-static inline struct dentry *
-kernfs_mount_ns(struct file_system_type *fs_type, int flags,
-		struct kernfs_root *root, unsigned long magic,
-		bool *new_sb_created, const void *ns)
-{ return ERR_PTR(-ENOSYS); }
+static inline int kernfs_get_tree(struct fs_context *fc)
+{ return -ENOSYS; }
+
+static inline void kernfs_free_fs_context(struct fs_context *fc) { }
 
 static inline void kernfs_kill_sb(struct super_block *sb) { }
 
@@ -477,10 +505,11 @@
  * @buf: buffer to copy @kn's name into
  * @buflen: size of @buf
  *
- * Builds and returns the full path of @kn in @buf of @buflen bytes.  The
- * path is built from the end of @buf so the returned pointer usually
- * doesn't match @buf.  If @buf isn't long enough, @buf is nul terminated
- * and %NULL is returned.
+ * If @kn is NULL result will be "(null)".
+ *
+ * Returns the length of the full path.  If the full length is equal to or
+ * greater than @buflen, @buf contains the truncated path with the trailing
+ * '\0'.  On error, -errno is returned.
  */
 static inline int kernfs_path(struct kernfs_node *kn, char *buf, size_t buflen)
 {
@@ -545,13 +574,4 @@
 	return kernfs_rename_ns(kn, new_parent, new_name, NULL);
 }
 
-static inline struct dentry *
-kernfs_mount(struct file_system_type *fs_type, int flags,
-		struct kernfs_root *root, unsigned long magic,
-		bool *new_sb_created)
-{
-	return kernfs_mount_ns(fs_type, flags, root,
-				magic, new_sb_created, NULL);
-}
-
 #endif	/* __LINUX_KERNFS_H */