dm: add helper macro for simple DM target module init and exit

Eliminate duplicate boilerplate code for simple modules that contain
a single DM target driver without any additional setup code.

Add a new module_dm() macro, which replaces the module_init() and
module_exit() with template functions that call dm_register_target()
and dm_unregister_target() respectively.

Signed-off-by: Yangtao Li <[e-mail]>
Signed-off-by: Mike Snitzer <[e-mail]>

drivers/md/dm-crypt.c

···
 	.iterate_devices = crypt_iterate_devices,
 	.io_hints = crypt_io_hints,
 };
-
-static int __init dm_crypt_init(void)
-{
-	return dm_register_target(&crypt_target);
-}
-
-static void __exit dm_crypt_exit(void)
-{
-	dm_unregister_target(&crypt_target);
-}
-
-module_init(dm_crypt_init);
-module_exit(dm_crypt_exit);
+module_dm(crypt);
 
 MODULE_AUTHOR("Jana Saout <[e-mail]>");
 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");

drivers/md/dm-delay.c

···
 	.status	     = delay_status,
 	.iterate_devices = delay_iterate_devices,
 };
-
-static int __init dm_delay_init(void)
-{
-	return dm_register_target(&delay_target);
-}
-
-static void __exit dm_delay_exit(void)
-{
-	dm_unregister_target(&delay_target);
-}
-
-/* Module hooks */
-module_init(dm_delay_init);
-module_exit(dm_delay_exit);
+module_dm(delay);
 
 MODULE_DESCRIPTION(DM_NAME " delay target");
 MODULE_AUTHOR("Heinz Mauelshagen <[e-mail]>");

drivers/md/dm-dust.c

···
 	.status = dust_status,
 	.prepare_ioctl = dust_prepare_ioctl,
 };
-
-static int __init dm_dust_init(void)
-{
-	return dm_register_target(&dust_target);
-}
-
-static void __exit dm_dust_exit(void)
-{
-	dm_unregister_target(&dust_target);
-}
-
-module_init(dm_dust_init);
-module_exit(dm_dust_exit);
+module_dm(dust);
 
 MODULE_DESCRIPTION(DM_NAME " dust test target");
 MODULE_AUTHOR("Bryan Gurney <[e-mail]>");

drivers/md/dm-ebs-target.c

···
 	.prepare_ioctl	 = ebs_prepare_ioctl,
 	.iterate_devices = ebs_iterate_devices,
 };
-
-static int __init dm_ebs_init(void)
-{
-	return dm_register_target(&ebs_target);
-}
-
-static void dm_ebs_exit(void)
-{
-	dm_unregister_target(&ebs_target);
-}
-
-module_init(dm_ebs_init);
-module_exit(dm_ebs_exit);
+module_dm(ebs);
 
 MODULE_AUTHOR("Heinz Mauelshagen <[e-mail]>");
 MODULE_DESCRIPTION(DM_NAME " emulated block size target");

drivers/md/dm-era-target.c

···
 	.iterate_devices = era_iterate_devices,
 	.io_hints = era_io_hints
 };
-
-static int __init dm_era_init(void)
-{
-	return dm_register_target(&era_target);
-}
-
-static void __exit dm_era_exit(void)
-{
-	dm_unregister_target(&era_target);
-}
-
-module_init(dm_era_init);
-module_exit(dm_era_exit);
+module_dm(era);
 
 MODULE_DESCRIPTION(DM_NAME " era target");
 MODULE_AUTHOR("Joe Thornber <[e-mail]>");

drivers/md/dm-flakey.c

···
 	.prepare_ioctl = flakey_prepare_ioctl,
 	.iterate_devices = flakey_iterate_devices,
 };
-
-static int __init dm_flakey_init(void)
-{
-	return dm_register_target(&flakey_target);
-}
-
-static void __exit dm_flakey_exit(void)
-{
-	dm_unregister_target(&flakey_target);
-}
-
-/* Module hooks */
-module_init(dm_flakey_init);
-module_exit(dm_flakey_exit);
+module_dm(flakey);
 
 MODULE_DESCRIPTION(DM_NAME " flakey target");
 MODULE_AUTHOR("Joe Thornber <[e-mail]>");

drivers/md/dm-log-writes.c

···
 	.dax_zero_page_range = log_writes_dax_zero_page_range,
 	.dax_recovery_write = log_writes_dax_recovery_write,
 };
-
-static int __init dm_log_writes_init(void)
-{
-	return dm_register_target(&log_writes_target);
-}
-
-static void __exit dm_log_writes_exit(void)
-{
-	dm_unregister_target(&log_writes_target);
-}
-
-module_init(dm_log_writes_init);
-module_exit(dm_log_writes_exit);
+module_dm(log_writes);
 
 MODULE_DESCRIPTION(DM_NAME " log writes target");
 MODULE_AUTHOR("Josef Bacik <[e-mail]>");

drivers/md/dm-raid.c

···
 	.preresume = raid_preresume,
 	.resume = raid_resume,
 };
-
-static int __init dm_raid_init(void)
-{
-	DMINFO("Loading target version %u.%u.%u",
-	       raid_target.version[0],
-	       raid_target.version[1],
-	       raid_target.version[2]);
-	return dm_register_target(&raid_target);
-}
-
-static void __exit dm_raid_exit(void)
-{
-	dm_unregister_target(&raid_target);
-}
-
-module_init(dm_raid_init);
-module_exit(dm_raid_exit);
+module_dm(raid);
 
 module_param(devices_handle_discard_safely, bool, 0644);
 MODULE_PARM_DESC(devices_handle_discard_safely,

drivers/md/dm-switch.c

···
 	.prepare_ioctl = switch_prepare_ioctl,
 	.iterate_devices = switch_iterate_devices,
 };
-
-static int __init dm_switch_init(void)
-{
-	return dm_register_target(&switch_target);
-}
-
-static void __exit dm_switch_exit(void)
-{
-	dm_unregister_target(&switch_target);
-}
-
-module_init(dm_switch_init);
-module_exit(dm_switch_exit);
+module_dm(switch);
 
 MODULE_DESCRIPTION(DM_NAME " dynamic path switching target");
 MODULE_AUTHOR("Kevin D. O'Kelley <[e-mail]>");

drivers/md/dm-unstripe.c

···
 	.iterate_devices = unstripe_iterate_devices,
 	.io_hints = unstripe_io_hints,
 };
-
-static int __init dm_unstripe_init(void)
-{
-	return dm_register_target(&unstripe_target);
-}
-
-static void __exit dm_unstripe_exit(void)
-{
-	dm_unregister_target(&unstripe_target);
-}
-
-module_init(dm_unstripe_init);
-module_exit(dm_unstripe_exit);
+module_dm(unstripe);
 
 MODULE_DESCRIPTION(DM_NAME " unstriped target");
 MODULE_ALIAS("dm-unstriped");

drivers/md/dm-verity-target.c

···
 	.iterate_devices = verity_iterate_devices,
 	.io_hints	= verity_io_hints,
 };
-
-static int __init dm_verity_init(void)
-{
-	return dm_register_target(&verity_target);
-}
-
-static void __exit dm_verity_exit(void)
-{
-	dm_unregister_target(&verity_target);
-}
-
-module_init(dm_verity_init);
-module_exit(dm_verity_exit);
+module_dm(verity);
 
 MODULE_AUTHOR("Mikulas Patocka <[e-mail]>");
 MODULE_AUTHOR("Mandeep Baines <[e-mail]>");

drivers/md/dm-writecache.c

···
 	.iterate_devices	= writecache_iterate_devices,
 	.io_hints		= writecache_io_hints,
 };
-
-static int __init dm_writecache_init(void)
-{
-	return dm_register_target(&writecache_target);
-}
-
-static void __exit dm_writecache_exit(void)
-{
-	dm_unregister_target(&writecache_target);
-}
-
-module_init(dm_writecache_init);
-module_exit(dm_writecache_exit);
+module_dm(writecache);
 
 MODULE_DESCRIPTION(DM_NAME " writecache target");
 MODULE_AUTHOR("Mikulas Patocka <[e-mail]>");

drivers/md/dm-zero.c

···
 	.map    = zero_map,
 	.io_hints = zero_io_hints,
 };
-
-static int __init dm_zero_init(void)
-{
-	return dm_register_target(&zero_target);
-}
-
-static void __exit dm_zero_exit(void)
-{
-	dm_unregister_target(&zero_target);
-}
-
-module_init(dm_zero_init)
-module_exit(dm_zero_exit)
+module_dm(zero);
 
 MODULE_AUTHOR("Jana Saout <[e-mail]>");
 MODULE_DESCRIPTION(DM_NAME " dummy target returning zeros");

drivers/md/dm-zoned-target.c

···
 	return r;
 }
 
-static struct target_type dmz_type = {
+static struct target_type zoned_target = {
 	.name		 = "zoned",
 	.version	 = {2, 0, 0},
 	.features	 = DM_TARGET_SINGLETON | DM_TARGET_MIXED_ZONED_MODEL,
···
 	.status		 = dmz_status,
 	.message	 = dmz_message,
 };
-
-static int __init dmz_init(void)
-{
-	return dm_register_target(&dmz_type);
-}
-
-static void __exit dmz_exit(void)
-{
-	dm_unregister_target(&dmz_type);
-}
-
-module_init(dmz_init);
-module_exit(dmz_exit);
+module_dm(zoned);
 
 MODULE_DESCRIPTION(DM_NAME " target for zoned block devices");
 MODULE_AUTHOR("Damien Le Moal <[e-mail]>");

include/linux/device-mapper.h

···
 		DMEMIT("target_name=%s,target_version=%u.%u.%u", \
 		       (y)->name, (y)->version[0], (y)->version[1], (y)->version[2])
 
+/**
+ * module_dm() - Helper macro for DM targets that don't do anything
+ * special in their module_init and module_exit.
+ * Each module may only use this macro once, and calling it replaces
+ * module_init() and module_exit().
+ *
+ * @name: DM target's name
+ */
+#define module_dm(name) \
+static int __init dm_##name##_init(void) \
+{ \
+	return dm_register_target(&(name##_target)); \
+} \
+module_init(dm_##name##_init) \
+static void __exit dm_##name##_exit(void) \
+{ \
+	dm_unregister_target(&(name##_target)); \
+} \
+module_exit(dm_##name##_exit)
+
 /*
  * Definitions of return values from target end_io function.
  */