At the end of __regmap_init(), if dev is not NULL, regmap_attach_dev()
is called, which adds a devres reference to the regmap, to be able to
retrieve a dev's regmap by name using dev_get_regmap().

When calling regmap_exit, the opposite does not happen, and the
reference is kept until the dev is detached.

Add a regmap_detach_dev() function and call it in regmap_exit() to make
sure that the devres reference is not kept.

Cc: stable@vger.kernel.org
Fixes: 72b39f6f2b5a ("regmap: Implement dev_get_regmap()")
Signed-off-by: Cosmin Tanislav <demonsingur@gmail.com>
---

V2:
 * switch to static function

V3:
 * move inter-version changelog after ---

V4:
 * remove mention of exporting the regmap_detach_dev() function

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 53131a7ede0a6..e3e2afc2c83c6 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -598,6 +598,17 @@ int regmap_attach_dev(struct device *dev, struct regmap *map,
 }
 EXPORT_SYMBOL_GPL(regmap_attach_dev);
 
+static int dev_get_regmap_match(struct device *dev, void *res, void *data);
+
+static int regmap_detach_dev(struct device *dev, struct regmap *map)
+{
+	if (!dev)
+		return 0;
+
+	return devres_release(dev, dev_get_regmap_release,
+			      dev_get_regmap_match, (void *)map->name);
+}
+
 static enum regmap_endian regmap_get_reg_endian(const struct regmap_bus *bus,
 					const struct regmap_config *config)
 {
@@ -1445,6 +1456,7 @@ void regmap_exit(struct regmap *map)
 {
 	struct regmap_async *async;
 
+	regmap_detach_dev(map->dev, map);
 	regcache_exit(map);
 
 	regmap_debugfs_exit(map);
-- 
2.47.0

On Thu, 28 Nov 2024 15:16:23 +0200, Cosmin Tanislav wrote:
> At the end of __regmap_init(), if dev is not NULL, regmap_attach_dev()
> is called, which adds a devres reference to the regmap, to be able to
> retrieve a dev's regmap by name using dev_get_regmap().
> 
> When calling regmap_exit, the opposite does not happen, and the
> reference is kept until the dev is detached.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap.git for-next

Thanks!

[1/1] regmap: detach regmap from dev on regmap_exit
      commit: 3061e170381af96d1e66799d34264e6414d428a7

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark