VFS: Make get_filesystem() return the affected filesystem

Make get_filesystem() return a pointer to the filesystem on which it just
got a ref.

Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/filesystems.c

@@ -33,9 +33,10 @@ static struct file_system_type *file_systems;
 static DEFINE_RWLOCK(file_systems_lock);
 
 /* WARNING: This can be used only if we _already_ own a reference */
-void get_filesystem(struct file_system_type *fs)
+struct file_system_type *get_filesystem(struct file_system_type *fs)
 {
 	__module_get(fs->owner);
+	return fs;
 }
 
 void put_filesystem(struct file_system_type *fs)

include/linux/fs.h

@@ -2956,7 +2956,7 @@ extern int generic_block_fiemap(struct inode *inode,
 				struct fiemap_extent_info *fieinfo, u64 start,
 				u64 len, get_block_t *get_block);
 
-extern void get_filesystem(struct file_system_type *fs);
+extern struct file_system_type *get_filesystem(struct file_system_type *fs);
 extern void put_filesystem(struct file_system_type *fs);
 extern struct file_system_type *get_fs_type(const char *name);
 extern struct super_block *get_super(struct block_device *);