[PATCH] change get_sb prototype

(i) The prototypes for free_vfsmnt(), alloc_vfsmnt(), do_kern_mount()
    so far occurred in several individual c files.  Now they are in
    <linux/mount.h>.

(ii) do_kern_mount() has a third argument name that is typically a
     constant.  It is called with "rootfs", "nfsd", type->name,
     "capifs", "usbdevfs", "binfmt_misc" etc.  So, it should have a
     prototype that expresses this:

	do_kern_mount(const char *fstype, int flags, const char *name, void *data);

This makes the ugly cast

-       return do_kern_mount(type->name, 0, (char *)type->name, NULL);
+       return do_kern_mount(type->name, 0, type->name, NULL);

go away. Now do_kern_mount() calls type->get_sb(), so also get_sb()
must have a const third argument. That is what the patch below does.

If I am not mistaken, precisely two filesystems do not treat this
argument as a constant, namely afs and cifs. A separate patch
gives some cleanup there.

3 files changed, 10 insertions, 6 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index de57729940ef..78b45c4afd9c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -919,7 +919,8 @@ struct file_system_type {
 	const char *name;
 	struct subsystem subsys;
 	int fs_flags;
-	struct super_block *(*get_sb) (struct file_system_type *, int, char *, void *);
+	struct super_block *(*get_sb) (struct file_system_type *, int,
+				       const char *, void *);
 	void (*kill_sb) (struct super_block *);
 	struct module *owner;
 	struct file_system_type * next;
@@ -927,7 +928,7 @@ struct file_system_type {
 };
 
 struct super_block *get_sb_bdev(struct file_system_type *fs_type,
-	int flags, char *dev_name, void * data,
+	int flags, const char *dev_name, void *data,
 	int (*fill_super)(struct super_block *, void *, int));
 struct super_block *get_sb_single(struct file_system_type *fs_type,
 	int flags, void *data,
@@ -1117,7 +1118,7 @@ extern void sync_filesystems(int wait);
 extern void emergency_sync(void);
 extern void emergency_remount(void);
 extern int do_remount_sb(struct super_block *sb, int flags,
-			void *data, int force);
+			 void *data, int force);
 extern sector_t bmap(struct inode *, sector_t);
 extern int setattr_mask(unsigned int);
 extern int notify_change(struct dentry *, struct iattr *);
diff --git a/include/linux/mount.h b/include/linux/mount.h
index d02e7845565a..d6996e7c7310 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -50,5 +50,10 @@ static inline void mntput(struct vfsmount *mnt)
 	}
 }
 
+extern void free_vfsmnt(struct vfsmount *mnt);
+extern struct vfsmount *alloc_vfsmnt(const char *name);
+extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
+				      const char *name, void *data);
+
 #endif
 #endif /* _LINUX_MOUNT_H */
diff --git a/include/linux/namespace.h b/include/linux/namespace.h
index acd64b4ca117..e7b313a202b6 100644
--- a/include/linux/namespace.h
+++ b/include/linux/namespace.h
@@ -12,9 +12,8 @@ struct namespace {
 	struct rw_semaphore	sem;
 };
 
-void umount_tree(struct vfsmount *mnt);
-
 extern void umount_tree(struct vfsmount *);
+extern int copy_namespace(int, struct task_struct *);
 
 static inline void put_namespace(struct namespace *namespace)
 {
@@ -38,7 +37,6 @@ static inline void exit_namespace(struct task_struct *p)
 		put_namespace(namespace);
 	}
 }
-extern int copy_namespace(int, struct task_struct *);
 
 static inline void get_namespace(struct namespace *namespace)
 {