[PATCH v2 0/7] regmap: cleanups for regcache and regmap init paths

[Peng Fan (OSS)]

Following up the previous regmap guard lock patchset [1].

[1] https://lore.kernel.org/all/179062150526.139547.3870545428656485907.b4-ty@b4/#r

This is the 2nd batch to do more cleanup.

This series tidies up locking, error handling, and resource management
across the regmap core and regcache.

- Extract regcache_locked_op() and regcache_locked_exit() helpers to
  replace open-coded lock/unlock pairs in regcache_init() and
  regcache_exit(), avoiding the cleanup.h-vs-goto concern that
  prevented the earlier scoped lock guard conversion.

- Extract __regcache_sync() to deduplicate the sync dispatch logic
  shared between regcache_sync() and regcache_sync_region().

- Flatten control flow in regcache_init(), regcache_lookup_reg(), and
  regcache_sync_block() by using early returns, moving guards into
  helpers, and merging redundant sanity checks.

- Switch regmap_register_patch() from krealloc() to krealloc_array()
  for overflow-safe element-count arithmetic.

- NULL map->reg_defaults after freeing in regcache_exit() to prevent
  a potential double-free if regmap_reinit_cache() later fails during
  cache re-initialisation.

Tested with the regmap KUnit suite (drivers/base/regmap/regmap-kunit.c)
with lockdep (PROVE_LOCKING, DEBUG_LOCK_ALLOC, DEBUG_ATOMIC_SLEEP) enabled.
Built clean with sparse (C=1).

Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
---
Changes in v2:
- Drop patches:
  [PATCH 5/7] regmap: use devm_kmemdup() for bus copies and remove free_on_exit
  [PATCH 6/7] regmap: return errors directly before map allocation in __regmap_init()
  sashiko reports a potential UAF issue regarding patch 5, so drop it.
  Patch 6 depends on patch 5, so also drop patch 6
- Add two new patches to do some cleanup to debugfs
  Patch v2 6/7 and 7/7
- Link to v1: https://patch.msgid.link/20260930-regmap-lock-2nd-v1-0-33a8a482f9ae@xxxxxxx

---
Peng Fan (7):
      regcache: extract locked helpers to replace open-coded lock/unlock pairs
      regcache: extract __regcache_sync() to deduplicate sync dispatch
      regcache: simplify control flow and reduce nesting
      regmap: use krealloc_array() in regmap_register_patch()
      regmap: fix potential double-free of map->reg_defaults on cache reinit
      regmap: debugfs: Use __free(kfree) in regmap_name_read_file()
      regmap: debugfs: Use guard to simplify code

 drivers/base/regmap/regcache.c       | 132 +++++++++++++++++------------------
 drivers/base/regmap/regmap-debugfs.c |  74 +++++++++-----------
 drivers/base/regmap/regmap.c         |  15 ++--
 3 files changed, 103 insertions(+), 118 deletions(-)
---
base-commit: 6474fa070f2b8013b4b87350b775b8c3be6e8aac
change-id: 20260930-regmap-lock-2nd-f481885c24d6

Best regards,
--  
Peng Fan <peng.fan@xxxxxxx>