linux-kernel - [PATCH 1/6] regulator: core: simplify regulator_lock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <0e37d1f09718a6ab9204b367ff528ab02df25ac7.1692484240.git.mirq-linux@rere.qmqm.pl>
Date:   Sun, 20 Aug 2023 00:46:08 +0200
From:   Michał Mirosław <mirq-linux@...e.qmqm.pl>
To:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
Cc:     linux-kernel@...r.kernel.org, Dmitry Osipenko <digetx@...il.com>,
        Douglas Anderson <dianders@...omium.org>
Subject: [PATCH 1/6] regulator: core: simplify regulator_lock_nested()

`lock` is only false when the `rdev` is already locked and the owner is
`current`. In this case `ret` is always zero. By removing `lock`, we
thus remove `mutex_owner` write avoidance, but make the code flow more
understandable.

Signed-off-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
---
 drivers/regulator/core.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index d8e1caaf207e..215b721e5cd4 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -141,27 +141,19 @@ static bool regulator_ops_is_valid(struct regulator_dev *rdev, int ops)
 static inline int regulator_lock_nested(struct regulator_dev *rdev,
 					struct ww_acquire_ctx *ww_ctx)
 {
-	bool lock = false;
 	int ret = 0;
 
 	mutex_lock(&regulator_nesting_mutex);
 
 	if (!ww_mutex_trylock(&rdev->mutex, ww_ctx)) {
-		if (rdev->mutex_owner == current)
-			rdev->ref_cnt++;
-		else
-			lock = true;
-
-		if (lock) {
+		if (rdev->mutex_owner != current) {
 			mutex_unlock(&regulator_nesting_mutex);
 			ret = ww_mutex_lock(&rdev->mutex, ww_ctx);
 			mutex_lock(&regulator_nesting_mutex);
 		}
-	} else {
-		lock = true;
 	}
 
-	if (lock && ret != -EDEADLK) {
+	if (ret != -EDEADLK) {
 		rdev->ref_cnt++;
 		rdev->mutex_owner = current;
 	}
-- 
2.39.2