fsverity: simplify handling of errors during initcall

Since CONFIG_FS_VERITY is a bool, not a tristate, fs/verity/ can only be
builtin or absent entirely; it can't be a loadable module.  Therefore,
the error code that gets returned from the fsverity_init() initcall is
never used.  If any part of the initcall does fail, which should never
happen, the kernel will be left in a bad state.

Following the usual convention for builtin code, just panic the kernel
if any of part of the initcall fails.

Link: https://lore.kernel.org/r/20230705212743.42180-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>

fs/verity/fsverity_private.h

@@ -118,8 +118,7 @@ void fsverity_free_info(struct fsverity_info *vi);
 int fsverity_get_descriptor(struct inode *inode,
 			    struct fsverity_descriptor **desc_ret);
 
-int __init fsverity_init_info_cache(void);
-void __init fsverity_exit_info_cache(void);
+void __init fsverity_init_info_cache(void);
 
 /* signature.c */
 
@@ -127,7 +126,7 @@ void __init fsverity_exit_info_cache(void);
 int fsverity_verify_signature(const struct fsverity_info *vi,
 			      const u8 *signature, size_t sig_size);
 
-int __init fsverity_init_signature(void);
+void __init fsverity_init_signature(void);
 #else /* !CONFIG_FS_VERITY_BUILTIN_SIGNATURES */
 static inline int
 fsverity_verify_signature(const struct fsverity_info *vi,
@@ -136,15 +135,13 @@ fsverity_verify_signature(const struct fsverity_info *vi,
 	return 0;
 }
 
-static inline int fsverity_init_signature(void)
+static inline void fsverity_init_signature(void)
 {
-	return 0;
 }
 #endif /* !CONFIG_FS_VERITY_BUILTIN_SIGNATURES */
 
 /* verify.c */
 
-int __init fsverity_init_workqueue(void);
-void __init fsverity_exit_workqueue(void);
+void __init fsverity_init_workqueue(void);
 
 #endif /* _FSVERITY_PRIVATE_H */

fs/verity/init.c

@@ -33,28 +33,10 @@ void fsverity_msg(const struct inode *inode, const char *level,
 
 static int __init fsverity_init(void)
 {
-	int err;
-
 	fsverity_check_hash_algs();
-
-	err = fsverity_init_info_cache();
-	if (err)
-		return err;
-
-	err = fsverity_init_workqueue();
-	if (err)
-		goto err_exit_info_cache;
-
-	err = fsverity_init_signature();
-	if (err)
-		goto err_exit_workqueue;
-
+	fsverity_init_info_cache();
+	fsverity_init_workqueue();
+	fsverity_init_signature();
 	return 0;
-
-err_exit_workqueue:
-	fsverity_exit_workqueue();
-err_exit_info_cache:
-	fsverity_exit_info_cache();
-	return err;
 }
 late_initcall(fsverity_init)

fs/verity/open.c

@@ -408,18 +408,10 @@ void __fsverity_cleanup_inode(struct inode *inode)
 }
 EXPORT_SYMBOL_GPL(__fsverity_cleanup_inode);
 
-int __init fsverity_init_info_cache(void)
+void __init fsverity_init_info_cache(void)
 {
-	fsverity_info_cachep = KMEM_CACHE_USERCOPY(fsverity_info,
-						   SLAB_RECLAIM_ACCOUNT,
-						   file_digest);
-	if (!fsverity_info_cachep)
-		return -ENOMEM;
-	return 0;
-}
-
-void __init fsverity_exit_info_cache(void)
-{
-	kmem_cache_destroy(fsverity_info_cachep);
-	fsverity_info_cachep = NULL;
+	fsverity_info_cachep = KMEM_CACHE_USERCOPY(
+					fsverity_info,
+					SLAB_RECLAIM_ACCOUNT | SLAB_PANIC,
+					file_digest);
 }

fs/verity/signature.c

@@ -109,43 +109,29 @@ static struct ctl_table fsverity_sysctl_table[] = {
 	{ }
 };
 
-static int __init fsverity_sysctl_init(void)
+static void __init fsverity_sysctl_init(void)
 {
-	fsverity_sysctl_header = register_sysctl("fs/verity", fsverity_sysctl_table);
-	if (!fsverity_sysctl_header) {
-		pr_err("sysctl registration failed!\n");
-		return -ENOMEM;
-	}
-	return 0;
+	fsverity_sysctl_header = register_sysctl("fs/verity",
+						 fsverity_sysctl_table);
+	if (!fsverity_sysctl_header)
+		panic("fsverity sysctl registration failed");
 }
 #else /* !CONFIG_SYSCTL */
-static inline int __init fsverity_sysctl_init(void)
+static inline void fsverity_sysctl_init(void)
 {
-	return 0;
 }
 #endif /* !CONFIG_SYSCTL */
 
-int __init fsverity_init_signature(void)
+void __init fsverity_init_signature(void)
 {
-	struct key *ring;
-	int err;
-
-	ring = keyring_alloc(".fs-verity", KUIDT_INIT(0), KGIDT_INIT(0),
-			     current_cred(), KEY_POS_SEARCH |
+	fsverity_keyring =
+		keyring_alloc(".fs-verity", KUIDT_INIT(0), KGIDT_INIT(0),
+			      current_cred(), KEY_POS_SEARCH |
 				KEY_USR_VIEW | KEY_USR_READ | KEY_USR_WRITE |
 				KEY_USR_SEARCH | KEY_USR_SETATTR,
-			     KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
-	if (IS_ERR(ring))
-		return PTR_ERR(ring);
+			      KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
+	if (IS_ERR(fsverity_keyring))
+		panic("failed to allocate \".fs-verity\" keyring");
 
-	err = fsverity_sysctl_init();
-	if (err)
-		goto err_put_ring;
-
-	fsverity_keyring = ring;
-	return 0;
-
-err_put_ring:
-	key_put(ring);
-	return err;
+	fsverity_sysctl_init();
 }

fs/verity/verify.c

@@ -346,7 +346,7 @@ void fsverity_enqueue_verify_work(struct work_struct *work)
 }
 EXPORT_SYMBOL_GPL(fsverity_enqueue_verify_work);
 
-int __init fsverity_init_workqueue(void)
+void __init fsverity_init_workqueue(void)
 {
 	/*
 	 * Use a high-priority workqueue to prioritize verification work, which
@@ -360,12 +360,5 @@ int __init fsverity_init_workqueue(void)
 						  WQ_HIGHPRI,
 						  num_online_cpus());
 	if (!fsverity_read_workqueue)
-		return -ENOMEM;
-	return 0;
-}
-
-void __init fsverity_exit_workqueue(void)
-{
-	destroy_workqueue(fsverity_read_workqueue);
-	fsverity_read_workqueue = NULL;
+		panic("failed to allocate fsverity_read_queue");
 }