regulator: core: Consistently set mutex_owner when using ww_mutex_loc…

…k_slow()

[ Upstream commit b83a177 ]

When a codepath locks a rdev using ww_mutex_lock_slow() directly then
that codepath is responsible for incrementing the "ref_cnt" and also
setting the "mutex_owner" to "current".

The regulator core consistently got that right for "ref_cnt" but
didn't always get it right for "mutex_owner". Let's fix this.

It's unlikely that this truly matters because the "mutex_owner" is
only needed if we're going to do subsequent locking of the same
rdev. However, even though it's not truly needed it seems less
surprising if we consistently set "mutex_owner" properly.

Fixes: f8702f9 ("regulator: core: Use ww_mutex for regulators locking")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20230329143317.RFC.v2.1.I4e9d433ea26360c06dd1381d091c82bb1a4ce843@changeid
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/regulator/core.c

@@ -334,6 +334,7 @@ static void regulator_lock_dependent(struct regulator_dev *rdev,
 			ww_mutex_lock_slow(&new_contended_rdev->mutex, ww_ctx);
 			old_contended_rdev = new_contended_rdev;
 			old_contended_rdev->ref_cnt++;
+			old_contended_rdev->mutex_owner = current;
 		}
 
 		err = regulator_lock_recursive(rdev,
@@ -6048,6 +6049,7 @@ static void regulator_summary_lock(struct ww_acquire_ctx *ww_ctx)
 			ww_mutex_lock_slow(&new_contended_rdev->mutex, ww_ctx);
 			old_contended_rdev = new_contended_rdev;
 			old_contended_rdev->ref_cnt++;
+			old_contended_rdev->mutex_owner = current;
 		}
 
 		err = regulator_summary_lock_all(ww_ctx,