From f9004dbfff8a3fbbd7e2a88c8a4327c7f2f8e5b2 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 31 Jan 2024 01:04:47 +0000
Subject: [PATCH] add driver 5G

---
 kernel/include/linux/kernfs.h |  141 +++++++++++++++++++++++++++++++----------------
 1 files changed, 93 insertions(+), 48 deletions(-)

diff --git a/kernel/include/linux/kernfs.h b/kernel/include/linux/kernfs.h
index 935e4b1..4434979 100644
--- a/kernel/include/linux/kernfs.h
+++ b/kernel/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
@@ -27,7 +26,9 @@
 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;
 
@@ -37,8 +38,10 @@
 	KERNFS_LINK		= 0x0004,
 };
 
-#define KERNFS_TYPE_MASK	0x000f
-#define KERNFS_FLAG_MASK	~KERNFS_TYPE_MASK
+#define KERNFS_TYPE_MASK		0x000f
+#define KERNFS_FLAG_MASK		~KERNFS_TYPE_MASK
+#define KERNFS_MAX_USER_XATTRS		128
+#define KERNFS_USER_XATTR_SIZE_LIMIT	(128 << 10)
 
 enum kernfs_node_flag {
 	KERNFS_ACTIVATED	= 0x0010,
@@ -63,7 +66,7 @@
 	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
@@ -78,6 +81,11 @@
 	 * fhandle to access nodes of the fs.
 	 */
 	KERNFS_ROOT_SUPPORT_EXPORTOP		= 0x0004,
+
+	/*
+	 * Support user xattrs to be written to nodes rooted at this root.
+	 */
+	KERNFS_ROOT_SUPPORT_USER_XATTR		= 0x0008,
 };
 
 /* type-specific structures for kernfs_node union members */
@@ -102,21 +110,6 @@
 	struct kernfs_open_node	*open;
 	loff_t			size;
 	struct kernfs_node	*notify_next;	/* for kernfs_notify() */
-};
-
-/* represent a kernfs node */
-union kernfs_node_id {
-	struct {
-		/*
-		 * blktrace will export this struct as a simplified 'struct
-		 * fid' (which is a big data struction), so userspace can use
-		 * it to find kernfs node. The layout must match the first two
-		 * fields of 'struct fid' exactly.
-		 */
-		u32		ino;
-		u32		generation;
-	};
-	u64			id;
 };
 
 /*
@@ -155,10 +148,17 @@
 
 	void			*priv;
 
-	union kernfs_node_id	id;
+	/*
+	 * 64bit unique ID.  On 64bit ino setups, id is the ino.  On 32bit,
+	 * the low 32bits are ino and upper generation.
+	 */
+	u64			id;
+
 	unsigned short		flags;
 	umode_t			mode;
 	struct kernfs_iattrs	*iattr;
+
+	ANDROID_KABI_RESERVE(1);
 };
 
 /*
@@ -169,7 +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,
@@ -193,14 +192,16 @@
 
 	/* private fields, do not use outside kernfs proper */
 	struct idr		ino_idr;
-	u32			last_ino;
-	u32			next_generation;
+	u32			last_id_lowbits;
+	u32			id_highbits;
 	struct kernfs_syscall_ops *syscall_ops;
 
 	/* list of kernfs_super_info of this root, protected by kernfs_mutex */
 	struct list_head	supers;
 
 	wait_queue_head_t	deactivate_waitq;
+
+	ANDROID_KABI_RESERVE(1);
 };
 
 struct kernfs_open_file {
@@ -221,6 +222,8 @@
 	bool			mmapped:1;
 	bool			released:1;
 	const struct vm_operations_struct *vm_ops;
+
+	ANDROID_KABI_RESERVE(1);
 };
 
 struct kernfs_ops {
@@ -282,11 +285,51 @@
 	ANDROID_KABI_RESERVE(2);
 };
 
+/*
+ * 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)
 {
 	return kn->flags & KERNFS_TYPE_MASK;
+}
+
+static inline ino_t kernfs_id_ino(u64 id)
+{
+	/* id is ino if ino_t is 64bit; otherwise, low 32bits */
+	if (sizeof(ino_t) >= sizeof(u64))
+		return id;
+	else
+		return (u32)id;
+}
+
+static inline u32 kernfs_id_gen(u64 id)
+{
+	/* gen is fixed at 1 if ino_t is 64bit; otherwise, high 32bits */
+	if (sizeof(ino_t) >= sizeof(u64))
+		return 1;
+	else
+		return id >> 32;
+}
+
+static inline ino_t kernfs_ino(struct kernfs_node *kn)
+{
+	return kernfs_id_ino(kn->id);
+}
+
+static inline ino_t kernfs_gen(struct kernfs_node *kn)
+{
+	return kernfs_id_gen(kn->id);
 }
 
 /**
@@ -368,17 +411,20 @@
 			     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);
 
-struct kernfs_node *kernfs_get_node_by_id(struct kernfs_root *root,
-	const union kernfs_node_id *id);
+struct kernfs_node *kernfs_find_and_get_node_by_id(struct kernfs_root *root,
+						   u64 id);
 #else	/* CONFIG_KERNFS */
 
 static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
@@ -472,14 +518,21 @@
 
 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) { }
 
@@ -493,10 +546,11 @@
  * @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)
 {
@@ -559,15 +613,6 @@
 				const char *new_name)
 {
 	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 */

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