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locking/mutex: Introduce devm_mutex_init()

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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().

Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: George Stark <gnstark@salutedevices.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Marek Behún <kabel@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/20240411161032.609544-2-gnstark@salutedevices.com
Signed-off-by: Lee Jones <lee@kernel.org>
This commit is contained in:
George Stark 2024-04-11 19:10:25 +03:00 committed by Lee Jones
parent 4cece76496
commit 4cd47222e4
2 changed files with 39 additions and 0 deletions
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27
include/linux/mutex.h
View File

@ -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 the 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.

12
kernel/locking/mutex-debug.c
View File

@ -12,6 +12,7 @@
*/
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/export.h>
#include <linux/poison.h>
#include <linux/sched.h>
@ -89,6 +90,17 @@ 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);
}
EXPORT_SYMBOL_GPL(__devm_mutex_init);
/***
* mutex_destroy - mark a mutex unusable
* @lock: the mutex to be destroyed