Re: [PATCH v4 4/4] drivers/thermal/exymos: Use guard notation when acquiring mutex
From: Krzysztof Kozlowski <krzk@kernel.org>
Date: 2025-03-11 17:30:14
Also in:
linux-pm, linux-samsung-soc, lkml
On 10/03/2025 15:34, Anand Moon wrote:
Using guard notation makes the code more compact and error handling more robust by ensuring that mutexes are released in all code paths when control leaves critical section.
Subject: typo, exynos
Signed-off-by: Anand Moon <redacted>
---
v4: used DEFINE_GUARD macro to guard exynos_tmu_data structure.
However, incorporating guard(exynos_tmu_data)(data); results
in a recursive deadlock with the mutex during initialization, as this
data structure is common to all the code configurations of Exynos TMU
v3: New patchIf you ever use cleanup or guards, you must build your code with recent clang and W=1. Failure to do so means you ask reviewers manually to spot issues not visible in the context, instead of using tools. It's a NAK for me.
quoted hunk ↗ jump to hunk
--- drivers/thermal/samsung/exynos_tmu.c | 25 +++++++++++-------------- 1 file changed, 11 insertions(+), 14 deletions(-)diff --git a/drivers/thermal/samsung/exynos_tmu.c b/drivers/thermal/samsung/exynos_tmu.c index a71cde0a4b17e..85f88c5e0f11c 100644 --- a/drivers/thermal/samsung/exynos_tmu.c +++ b/drivers/thermal/samsung/exynos_tmu.c@@ -12,6 +12,7 @@ */ #include <linux/clk.h> +#include <linux/cleanup.h> #include <linux/io.h> #include <linux/interrupt.h> #include <linux/module.h>@@ -199,6 +200,9 @@ struct exynos_tmu_data { void (*tmu_clear_irqs)(struct exynos_tmu_data *data); }; +DEFINE_GUARD(exynos_tmu_data, struct exynos_tmu_data *,
I do not understand why do you need custom guard.
quoted hunk ↗ jump to hunk
+ mutex_lock(&_T->lock), mutex_unlock(&_T->lock)) + /* * TMU treats temperature as a mapped temperature code. * The temperature is converted differently depending on the calibration type.@@ -256,7 +260,7 @@ static int exynos_tmu_initialize(struct platform_device *pdev) unsigned int status; int ret = 0; - mutex_lock(&data->lock); + guard(mutex)(&data->lock);
Which you do not use... Please don't use cleanup.h if you do not know it. It leads to bugs. Best regards, Krzysztof