[PATCH 2/2] nvme: keyring: fix conditional compilation

[Keith Busch]

On Fri, Oct 27, 2023 at 11:21:50AM +0200, Christoph Hellwig wrote:
> On Fri, Oct 27, 2023 at 11:08:23AM +0200, Hannes Reinecke wrote:
> > obj-$(CONFIG_MOD1)	+= mod1.o mod-common.o
> > obj-$(CONFIG_MOD2)	+= mod2.o mod-common.o
> >
> > and mod-common contains a 'module_init()' and a 'module_exit()' function, 
> > what happens if I load mod2 after mod1?
> 
> mod-common is already loaded and won't be loaded again.
> 
> > And what happens if I unload mod2, but keep mod1?
> 
> mod-common doesn't become available for unloading until all
> modules using it are unloaded first.

Looks like this works, atop patch 1:

---
diff --git a/drivers/nvme/common/keyring.c b/drivers/nvme/common/keyring.c
index 46d7a537dbc2e..c35b3a287a910 100644
--- a/drivers/nvme/common/keyring.c
+++ b/drivers/nvme/common/keyring.c
@@ -151,7 +151,7 @@ key_serial_t nvme_tls_psk_default(struct key *keyring,
 }
 EXPORT_SYMBOL_GPL(nvme_tls_psk_default);
 
-int nvme_keyring_init(void)
+static int __init nvme_keyring_init(void)
 {
 	int err;
 
@@ -171,14 +171,14 @@ int nvme_keyring_init(void)
 	}
 	return 0;
 }
-EXPORT_SYMBOL_GPL(nvme_keyring_init);
 
-void nvme_keyring_exit(void)
+static void __exit nvme_keyring_exit(void)
 {
 	unregister_key_type(&nvme_tls_psk_key_type);
 	key_revoke(nvme_keyring);
 	key_put(nvme_keyring);
 }
-EXPORT_SYMBOL_GPL(nvme_keyring_exit);
 
 MODULE_LICENSE("GPL v2");
+module_init(nvme_keyring_init);
+module_exit(nvme_keyring_exit);
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 75a1b58a7a436..683b694afdead 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4737,16 +4737,11 @@ static int __init nvme_core_init(void)
 		result = PTR_ERR(nvme_ns_chr_class);
 		goto unregister_generic_ns;
 	}
-	result = nvme_keyring_init();
-	if (result)
-		goto destroy_ns_chr;
 	result = nvme_init_auth();
 	if (result)
-		goto keyring_exit;
+		goto destroy_ns_chr;
 	return 0;
 
-keyring_exit:
-	nvme_keyring_exit();
 destroy_ns_chr:
 	class_destroy(nvme_ns_chr_class);
 unregister_generic_ns:
@@ -4770,7 +4765,6 @@ static int __init nvme_core_init(void)
 static void __exit nvme_core_exit(void)
 {
 	nvme_exit_auth();
-	nvme_keyring_exit();
 	class_destroy(nvme_ns_chr_class);
 	class_destroy(nvme_subsys_class);
 	class_destroy(nvme_class);
diff --git a/include/linux/nvme-keyring.h b/include/linux/nvme-keyring.h
index 4efea9dd967c1..f4f6634e85846 100644
--- a/include/linux/nvme-keyring.h
+++ b/include/linux/nvme-keyring.h
diff --git a/drivers/nvme/common/keyring.c b/drivers/nvme/common/keyring.c
index 46d7a537dbc2e..c35b3a287a910 100644
--- a/drivers/nvme/common/keyring.c
+++ b/drivers/nvme/common/keyring.c
@@ -151,7 +151,7 @@ key_serial_t nvme_tls_psk_default(struct key *keyring,
 }
 EXPORT_SYMBOL_GPL(nvme_tls_psk_default);
 
-int nvme_keyring_init(void)
+static int __init nvme_keyring_init(void)
 {
 	int err;
 
@@ -171,14 +171,14 @@ int nvme_keyring_init(void)
 	}
 	return 0;
 }
-EXPORT_SYMBOL_GPL(nvme_keyring_init);
 
-void nvme_keyring_exit(void)
+static void __exit nvme_keyring_exit(void)
 {
 	unregister_key_type(&nvme_tls_psk_key_type);
 	key_revoke(nvme_keyring);
 	key_put(nvme_keyring);
 }
-EXPORT_SYMBOL_GPL(nvme_keyring_exit);
 
 MODULE_LICENSE("GPL v2");
+module_init(nvme_keyring_init);
+module_exit(nvme_keyring_exit);
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 75a1b58a7a436..683b694afdead 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4737,16 +4737,11 @@ static int __init nvme_core_init(void)
 		result = PTR_ERR(nvme_ns_chr_class);
 		goto unregister_generic_ns;
 	}
-	result = nvme_keyring_init();
-	if (result)
-		goto destroy_ns_chr;
 	result = nvme_init_auth();
 	if (result)
-		goto keyring_exit;
+		goto destroy_ns_chr;
 	return 0;
 
-keyring_exit:
-	nvme_keyring_exit();
 destroy_ns_chr:
 	class_destroy(nvme_ns_chr_class);
 unregister_generic_ns:
@@ -4770,7 +4765,6 @@ static int __init nvme_core_init(void)
 static void __exit nvme_core_exit(void)
 {
 	nvme_exit_auth();
-	nvme_keyring_exit();
 	class_destroy(nvme_ns_chr_class);
 	class_destroy(nvme_subsys_class);
 	class_destroy(nvme_class);
diff --git a/include/linux/nvme-keyring.h b/include/linux/nvme-keyring.h
index 4efea9dd967c1..f4f6634e85846 100644
--- a/include/linux/nvme-keyring.h
+++ b/include/linux/nvme-keyring.h
@@ -6,14 +6,12 @@
 #ifndef _NVME_KEYRING_H
 #define _NVME_KEYRING_H
 
-#ifdef CONFIG_NVME_KEYRING
+#if IS_ENABLED(CONFIG_NVME_KEYRING)
 
 key_serial_t nvme_tls_psk_default(struct key *keyring,
 		const char *hostnqn, const char *subnqn);
 
 key_serial_t nvme_keyring_id(void);
-int nvme_keyring_init(void);
-void nvme_keyring_exit(void);
 
 #else
 
@@ -26,11 +24,6 @@ static inline key_serial_t nvme_keyring_id(void)
 {
 	return 0;
 }
-static inline int nvme_keyring_init(void)
-{
-	return 0;
-}
-static inline void nvme_keyring_exit(void) {}
 
 #endif /* !CONFIG_NVME_KEYRING */
 #endif /* _NVME_KEYRING_H */
@@ -6,14 +6,12 @@
 #ifndef _NVME_KEYRING_H
 #define _NVME_KEYRING_H
 
-#ifdef CONFIG_NVME_KEYRING
+#if IS_ENABLED(CONFIG_NVME_KEYRING)
 
 key_serial_t nvme_tls_psk_default(struct key *keyring,
 		const char *hostnqn, const char *subnqn);
 
 key_serial_t nvme_keyring_id(void);
-int nvme_keyring_init(void);
-void nvme_keyring_exit(void);
 
 #else
 
@@ -26,11 +24,6 @@ static inline key_serial_t nvme_keyring_id(void)
 {
 	return 0;
 }
-static inline int nvme_keyring_init(void)
-{
-	return 0;
-}
-static inline void nvme_keyring_exit(void) {}
 
 #endif /* !CONFIG_NVME_KEYRING */
 #endif /* _NVME_KEYRING_H */
--