From: Waiman Long <longman@redhat.com>
To: George Stark <gnstark@salutedevices.com>,
andy.shevchenko@gmail.com, pavel@ucw.cz, lee@kernel.org,
vadimp@nvidia.com, mpe@ellerman.id.au, npiggin@gmail.com,
christophe.leroy@csgroup.eu, hdegoede@redhat.com,
mazziesaccount@gmail.com, peterz@infradead.org, mingo@redhat.com,
will@kernel.org, boqun.feng@gmail.com, nikitos.tr@gmail.com,
marek.behun@nic.cz, kabel@kernel.org
Cc: linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, kernel@salutedevices.com
Subject: Re: [PATCH v6 1/9] locking/mutex: introduce devm_mutex_init
Date: Thu, 14 Mar 2024 09:32:48 -0400 [thread overview]
Message-ID: <9fe2eaef-0407-4a96-b603-e7f6579110b6@redhat.com> (raw)
In-Reply-To: <20240314084531.1935545-2-gnstark@salutedevices.com>
On 3/14/24 04:45, George Stark wrote:
> Using of devm API leads to a certain order of releasing resources.
> So all dependent resources which are not devm-wrapped should be deleted
> with respect to devm-release order. Mutex is one of such objects that
> often is bound to other resources and has no own devm wrapping.
> Since mutex_destroy() actually does nothing in non-debug builds
> frequently calling mutex_destroy() is just ignored which is safe for now
> but wrong formally and can lead to a problem if mutex_destroy() will be
> extended so introduce devm_mutex_init()
>
> Signed-off-by: George Stark <gnstark@salutedevices.com>
> Suggested by-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
> include/linux/mutex.h | 27 +++++++++++++++++++++++++++
> kernel/locking/mutex-debug.c | 11 +++++++++++
> 2 files changed, 38 insertions(+)
>
> diff --git a/include/linux/mutex.h b/include/linux/mutex.h
> index 67edc4ca2bee..f57e005ded24 100644
> --- a/include/linux/mutex.h
> +++ b/include/linux/mutex.h
> @@ -22,6 +22,8 @@
> #include <linux/cleanup.h>
> #include <linux/mutex_types.h>
>
> +struct device;
> +
> #ifdef CONFIG_DEBUG_LOCK_ALLOC
> # define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
> , .dep_map = { \
> @@ -117,6 +119,31 @@ do { \
> } while (0)
> #endif /* CONFIG_PREEMPT_RT */
>
> +#ifdef CONFIG_DEBUG_MUTEXES
> +
> +int __devm_mutex_init(struct device *dev, struct mutex *lock);
> +
> +#else
> +
> +static inline int __devm_mutex_init(struct device *dev, struct mutex *lock)
> +{
> + /*
> + * When CONFIG_DEBUG_MUTEXES is off mutex_destroy is just a nop so
> + * no really need to register it in devm subsystem.
> + */
> + return 0;
> +}
> +
> +#endif
> +
> +#define devm_mutex_init(dev, mutex) \
> +({ \
> + typeof(mutex) mutex_ = (mutex); \
> + \
> + mutex_init(mutex_); \
> + __devm_mutex_init(dev, mutex_); \
> +})
> +
> /*
> * See kernel/locking/mutex.c for detailed documentation of these APIs.
> * Also see Documentation/locking/mutex-design.rst.
> diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
> index bc8abb8549d2..6aa77e3dc82e 100644
> --- a/kernel/locking/mutex-debug.c
> +++ b/kernel/locking/mutex-debug.c
> @@ -19,6 +19,7 @@
> #include <linux/kallsyms.h>
> #include <linux/interrupt.h>
> #include <linux/debug_locks.h>
> +#include <linux/device.h>
>
> #include "mutex.h"
>
> @@ -89,6 +90,16 @@ void debug_mutex_init(struct mutex *lock, const char *name,
> lock->magic = lock;
> }
>
> +static void devm_mutex_release(void *res)
> +{
> + mutex_destroy(res);
> +}
> +
> +int __devm_mutex_init(struct device *dev, struct mutex *lock)
> +{
> + return devm_add_action_or_reset(dev, devm_mutex_release, lock);
> +}
> +
> /***
> * mutex_destroy - mark a mutex unusable
> * @lock: the mutex to be destroyed
Acked-by: Waiman Long <longman@redhat.com>
next prev parent reply other threads:[~2024-03-14 13:32 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-14 8:45 [PATCH v6 0/9] devm_led_classdev_register() usage problem George Stark
2024-03-14 8:45 ` [PATCH v6 1/9] locking/mutex: introduce devm_mutex_init George Stark
2024-03-14 9:02 ` Christophe Leroy
2024-03-14 10:33 ` Andy Shevchenko
2024-03-14 10:40 ` Marek Behún
2024-03-14 13:32 ` Waiman Long [this message]
2024-03-14 8:45 ` [PATCH v6 2/9] leds: aw2013: use devm API to cleanup module's resources George Stark
2024-03-14 8:45 ` [PATCH v6 3/9] leds: aw200xx: " George Stark
2024-03-14 8:45 ` [PATCH v6 4/9] leds: lp3952: " George Stark
2024-03-14 8:45 ` [PATCH v6 5/9] leds: lm3532: " George Stark
2024-03-14 8:45 ` [PATCH v6 6/9] leds: nic78bx: " George Stark
2024-03-14 8:45 ` [PATCH v6 7/9] leds: mlxreg: use devm_mutex_init for mutex initializtion George Stark
2024-03-14 8:45 ` [PATCH v6 8/9] leds: an30259a: use devm_mutext_init for mutext initialization George Stark
2024-03-14 8:45 ` [PATCH v6 9/9] leds: powernv: use LED_RETAIN_AT_SHUTDOWN flag for leds George Stark
2024-03-14 10:34 ` Andy Shevchenko
2024-03-14 10:37 ` [PATCH v6 0/9] devm_led_classdev_register() usage problem Andy Shevchenko
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