[tip: locking/core] nvdimm: Convert nvdimm_bus guard to class

["tip-bot2 for Dmitry Ilvokhin" <tip-bot2@linutronix.de>]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     813e5598e5b551a1fb82b516428ce2f135921122
Gitweb:        https://git.kernel.org/tip/813e5598e5b551a1fb82b516428ce2f135921122
Author:        Dmitry Ilvokhin <d@ilvokhin.com>
AuthorDate:    Tue, 02 Jun 2026 07:12:50 
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Wed, 03 Jun 2026 11:38:47 +02:00

nvdimm: Convert nvdimm_bus guard to class

The nvdimm_bus guard accepts NULL and skips locking when NULL is passed.
Convert from DEFINE_GUARD() to DEFINE_CLASS() + DEFINE_CLASS_IS_GUARD().

This is a preparatory change for making DEFINE_GUARD() constructors
__nonnull_args(). nvdimm_bus legitimately passes NULL, so it must be
adjusted to avoid a compile error.

No functional change.

Signed-off-by: Dmitry Ilvokhin <d@ilvokhin.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://patch.msgid.link/8c0417904d280896ecf2e9923ffa9f20076f59b8.1780064327.git.d@ilvokhin.com
---
 drivers/nvdimm/nd.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index b199eea..18b6455 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -632,8 +632,11 @@ u64 nd_region_interleave_set_cookie(struct nd_region *nd_region,
 u64 nd_region_interleave_set_altcookie(struct nd_region *nd_region);
 void nvdimm_bus_lock(struct device *dev);
 void nvdimm_bus_unlock(struct device *dev);
-DEFINE_GUARD(nvdimm_bus, struct device *,
-	     if (_T) nvdimm_bus_lock(_T), if (_T) nvdimm_bus_unlock(_T));
+DEFINE_CLASS(nvdimm_bus, struct device *,
+	     if (_T) nvdimm_bus_unlock(_T),
+	     ({ if (_T) nvdimm_bus_lock(_T); _T; }),
+	     struct device *_T);
+DEFINE_CLASS_IS_GUARD(nvdimm_bus);
 
 bool is_nvdimm_bus_locked(struct device *dev);
 void nvdimm_check_and_set_ro(struct gendisk *disk);