regmap: convert map->lock/unlock users to a scoped guard

Peng Fan (OSS) <peng.fan@oss.nxp.com> says:

The regmap lock is taken by calling the lock and unlock callbacks
directly at every call site:

	map->lock(map->lock_arg);
	...
	map->unlock(map->lock_arg);

The open-coded pattern forces every error path to unlock by hand,
which spreads goto out_unlock chains and duplicated unlock statements
throughout regmap.c and regcache.c and makes it easy to leak the lock
on a newly added return path.

Define a scoped guard for the regmap lock (DEFINE_GUARD) in internal.h
and convert the users to it. The lock and unlock callbacks are chosen
at init time (mutex, spinlock, raw spinlock, hwspinlock or none) and
return void, so an unconditional guard is sufficient. Function-scope
critical sections use guard(regmap)(); sites that must run work after
the lock is dropped - for example regmap_register_patch() calling
regmap_async_complete() and the debugfs cache_only handler calling
regcache_sync() (which takes the lock itself) - use
scoped_guard(regmap, ...) so the trailing work stays outside the
guarded region.

regcache_sync() and regcache_sync_region() are deliberately left
unconverted: they already use a single goto out unlock path, so a
guard would save nothing while forcing either a goto inside a
scoped_guard scope or a control-flow rewrite, neither of which is an
improvement.

This patchset removes many manual unlock statements together with the
associated goto out_unlock labels.

The series is split to keep the regcache: and regmap: changes on their
own commits and to preserve independent revertibility:

  1. define the guard and convert regmap.c
  2. convert regcache.c (except the sync helpers, see above)
  3. convert the regcache rbtree debugfs dump
  4. convert the regmap debugfs write handlers

No functional change.

Tested with the regmap KUnit suite (drivers/base/regmap/regmap-kunit.c)
under ARCH=um: 551/551 tests pass, and 551/551 again with lockdep
(PROVE_LOCKING, DEBUG_LOCK_ALLOC, DEBUG_ATOMIC_SLEEP) enabled with no
splats. Built clean with sparse (C=1) showing no lock-context
imbalance warnings.

Link: https://patch.msgid.link/20260924-regmap-lock-guard-v3-0-8a6127223c16@nxp.com

1 files changed, 1 insertions, 1 deletions

diff --git a/scripts/livepatch/init.c b/scripts/livepatch/init.c
index f14d8c8fb35f..16aff8f736eb 100644
--- a/scripts/livepatch/init.c
+++ b/scripts/livepatch/init.c
@@ -51,7 +51,7 @@ static int __init livepatch_mod_init(void)
 		if (!funcs) {
 			ret = -ENOMEM;
 			for (int j = 0; j < i; j++)
-				kfree(objs[i].funcs);
+				kfree(objs[j].funcs);
 			goto err_free_objs;
 		}