Message-Id: <20230409164339.60919-1-frank.li@vivo.com>
Date:   Mon, 10 Apr 2023 00:43:37 +0800
From:   Yangtao Li <frank.li@...o.com>
To:     Alasdair Kergon <agk@...hat.com>,
        Mike Snitzer <snitzer@...nel.org>, dm-devel@...hat.com
Cc:     Yangtao Li <frank.li@...o.com>, linux-kernel@...r.kernel.org
Subject: [PATCH] dm: add helper macro for device mapper target driver boilerplate

For simple modules that contain a single device mapper target driver
without any additional setup code then ends up being a block of duplicated
boilerplate. This patch adds a new macro, module_dm(), which replaces
the module_init()/module_exit() registrations with template functions.

Signed-off-by: Yangtao Li <frank.li@...o.com>
---
 drivers/md/dm-crypt.c         | 14 +-------------
 drivers/md/dm-delay.c         | 15 +--------------
 drivers/md/dm-dust.c          | 14 +-------------
 drivers/md/dm-ebs-target.c    | 14 +-------------
 drivers/md/dm-era-target.c    | 14 +-------------
 drivers/md/dm-flakey.c        | 15 +--------------
 drivers/md/dm-log-writes.c    | 14 +-------------
 drivers/md/dm-raid.c          | 18 +-----------------
 drivers/md/dm-switch.c        | 14 +-------------
 drivers/md/dm-target.c        |  3 +++
 drivers/md/dm-unstripe.c      | 14 +-------------
 drivers/md/dm-verity-target.c | 14 +-------------
 drivers/md/dm-writecache.c    | 14 +-------------
 drivers/md/dm-zero.c          | 14 +-------------
 drivers/md/dm-zoned-target.c  | 16 ++--------------
 include/linux/device-mapper.h | 20 ++++++++++++++++++++
 16 files changed, 38 insertions(+), 189 deletions(-)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 52615a258e13..8b47b913ee83 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -3659,19 +3659,7 @@ static struct target_type crypt_target = {
 	.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 <jana@...ut.de>");
 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c
index 00d18b2070a5..7433525e5985 100644
--- a/drivers/md/dm-delay.c
+++ b/drivers/md/dm-delay.c
@@ -367,20 +367,7 @@ static struct target_type delay_target = {
 	.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 <mauelshagen@...hat.com>");
diff --git a/drivers/md/dm-dust.c b/drivers/md/dm-dust.c
index 9bf3cdf548de..12a377e06d02 100644
--- a/drivers/md/dm-dust.c
+++ b/drivers/md/dm-dust.c
@@ -570,19 +570,7 @@ static struct target_type dust_target = {
 	.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 <dm-devel@...hat.com>");
diff --git a/drivers/md/dm-ebs-target.c b/drivers/md/dm-ebs-target.c
index 38da4de3ecbf..435b45201f4d 100644
--- a/drivers/md/dm-ebs-target.c
+++ b/drivers/md/dm-ebs-target.c
@@ -452,19 +452,7 @@ static struct target_type ebs_target = {
 	.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 <dm-devel@...hat.com>");
 MODULE_DESCRIPTION(DM_NAME " emulated block size target");
diff --git a/drivers/md/dm-era-target.c b/drivers/md/dm-era-target.c
index 554d234fca18..0d70914217ee 100644
--- a/drivers/md/dm-era-target.c
+++ b/drivers/md/dm-era-target.c
@@ -1753,19 +1753,7 @@ static struct target_type era_target = {
 	.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 <ejt@...hat.com>");
diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index 14179355e6a1..ebcfb99b186b 100644
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -506,20 +506,7 @@ static struct target_type flakey_target = {
 	.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 <dm-devel@...hat.com>");
diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c
index 6d7436d2fd7f..f17a6cf2284e 100644
--- a/drivers/md/dm-log-writes.c
+++ b/drivers/md/dm-log-writes.c
@@ -937,19 +937,7 @@ static struct target_type log_writes_target = {
 	.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 <jbacik@...com>");
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 2dfd51509647..c8821fcb8299 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -4077,23 +4077,7 @@ static struct target_type raid_target = {
 	.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,
diff --git a/drivers/md/dm-switch.c b/drivers/md/dm-switch.c
index 5a5976b0cfb8..dfd9fb52a6f3 100644
--- a/drivers/md/dm-switch.c
+++ b/drivers/md/dm-switch.c
@@ -565,19 +565,7 @@ static struct target_type switch_target = {
 	.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 <Kevin_OKelley@...l.com>");
diff --git a/drivers/md/dm-target.c b/drivers/md/dm-target.c
index 9e9871361440..a6381cf376c1 100644
--- a/drivers/md/dm-target.c
+++ b/drivers/md/dm-target.c
@@ -84,6 +84,9 @@ int dm_register_target(struct target_type *tt)
 {
 	int rv = 0;
 
+	DMINFO("Loading '%s' target version %u.%u.%u",
+		tt->name, tt->version[0], tt->version[1], tt->version[2]);
+
 	down_write(&_lock);
 	if (__find_target_type(tt->name)) {
 		DMERR("%s: cannot find '%s' target",
diff --git a/drivers/md/dm-unstripe.c b/drivers/md/dm-unstripe.c
index e7b7d5983a16..48587c16c445 100644
--- a/drivers/md/dm-unstripe.c
+++ b/drivers/md/dm-unstripe.c
@@ -192,19 +192,7 @@ static struct target_type unstripe_target = {
 	.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");
diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 260f04d12982..e35c16e06d06 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -1514,19 +1514,7 @@ static struct target_type verity_target = {
 	.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 <mpatocka@...hat.com>");
 MODULE_AUTHOR("Mandeep Baines <msb@...omium.org>");
diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 81b60b75a9fa..074cb785eafc 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -2773,19 +2773,7 @@ static struct target_type writecache_target = {
 	.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 <dm-devel@...hat.com>");
diff --git a/drivers/md/dm-zero.c b/drivers/md/dm-zero.c
index 884ac726a743..3b13e6eb1aa4 100644
--- a/drivers/md/dm-zero.c
+++ b/drivers/md/dm-zero.c
@@ -75,19 +75,7 @@ static struct target_type zero_target = {
 	.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 <jana@...ut.de>");
 MODULE_DESCRIPTION(DM_NAME " dummy target returning zeros");
diff --git a/drivers/md/dm-zoned-target.c b/drivers/md/dm-zoned-target.c
index ad4764dcd013..ad8e670a2f9b 100644
--- a/drivers/md/dm-zoned-target.c
+++ b/drivers/md/dm-zoned-target.c
@@ -1138,7 +1138,7 @@ static int dmz_message(struct dm_target *ti, unsigned int argc, char **argv,
 	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,
@@ -1154,19 +1154,7 @@ static struct target_type dmz_type = {
 	.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 <damien.lemoal@....com>");
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 8aa6b3ea91fa..9d79ce428b62 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -631,6 +631,26 @@ void dm_destroy_crypto_profile(struct blk_crypto_profile *profile);
 		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 drivers that don't do anything
+ * special in module init/exit. This eliminates a lot of boilerplate.
+ * Each module may only use this macro once, and calling it replaces
+ * module_init() and module_exit().
+ *
+ * @name: device mapper 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.
  */
-- 
2.35.1

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