mm: shmem: make shmem_init return void

The return value of shmem_init is never used.  So we can make it return
void now.

[akpm@linux-foundation.org: remove `return;' from void-returning function, per Muchun Song]
Link: https://lkml.kernel.org/r/20220328112707.22217-1-linmiaohe@huawei.comSigned-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/shmem_fs.h

@@ -56,7 +56,7 @@ static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
  * Functions in mm/shmem.c called directly from elsewhere:
  */
 extern const struct fs_parameter_spec shmem_fs_parameters[];
-extern int shmem_init(void);
+extern void shmem_init(void);
 extern int shmem_init_fs_context(struct fs_context *fc);
 extern struct file *shmem_file_setup(const char *name,
 					loff_t size, unsigned long flags);

mm/shmem.c

@@ -3888,7 +3888,7 @@ static struct file_system_type shmem_fs_type = {
 	.fs_flags	= FS_USERNS_MOUNT,
 };
 
-int __init shmem_init(void)
+void __init shmem_init(void)
 {
 	int error;
 
@@ -3913,14 +3913,13 @@ int __init shmem_init(void)
 	else
 		shmem_huge = SHMEM_HUGE_NEVER; /* just in case it was patched */
 #endif
-	return 0;
+	return;
 
 out1:
 	unregister_filesystem(&shmem_fs_type);
 out2:
 	shmem_destroy_inodecache();
 	shm_mnt = ERR_PTR(error);
-	return error;
 }
 
 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && defined(CONFIG_SYSFS)
@@ -3998,14 +3997,12 @@ static struct file_system_type shmem_fs_type = {
 	.fs_flags	= FS_USERNS_MOUNT,
 };
 
-int __init shmem_init(void)
+void __init shmem_init(void)
 {
 	BUG_ON(register_filesystem(&shmem_fs_type) != 0);
 
 	shm_mnt = kern_mount(&shmem_fs_type);
 	BUG_ON(IS_ERR(shm_mnt));
-
-	return 0;
 }
 
 int shmem_unuse(unsigned int type)