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Subject: Re: [PATCH v5 02/10] locking/mutex: introduce devm_mutex_init

Hello Christophe

On 3/12/24 14:51, Christophe Leroy wrote:
>
>
> Le 12/03/2024 à 12:39, George Stark a écrit :
>> [Vous ne recevez pas souvent de courriers de [email protected].
>> Découvrez pourquoi ceci est important à
>> https://aka.ms/LearnAboutSenderIdentification ]

..

> You don't need that inline function, just change debug_devm_mutex_init()
> to __devm_mutex_init().

I stuck to debug_* name because mutex-debug.c already exports a set
of debug_ calls so...
Well it's not essential anyway. Here's the next try:

diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index 67edc4ca2bee..537b5ea18ceb 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 +119,29 @@ 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) \
+({ \
+ 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
--
2.25.1

>> +
>> +#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.
>> +       */
>
> Don't know if it is because tabs are replaced by blanks in you email,
> but the stars should be aligned

Ack

--
Best regards
George

2024-03-12 18:17:41

by Christophe Leroy

[permalink] [raw]

Subject: Re: [PATCH v5 02/10] locking/mutex: introduce devm_mutex_init

Le 12/03/2024 à 16:30, George Stark a écrit :
> [Vous ne recevez pas souvent de courriers de [email protected].
> Découvrez pourquoi ceci est important à
> https://aka.ms/LearnAboutSenderIdentification ]
>
> Hello Christophe
>
> On 3/12/24 14:51, Christophe Leroy wrote:
>>
>>
>> Le 12/03/2024 à 12:39, George Stark a écrit :
>>> [Vous ne recevez pas souvent de courriers de [email protected].
>>> Découvrez pourquoi ceci est important à
>>> https://aka.ms/LearnAboutSenderIdentification ]
>
> ...
>
>> You don't need that inline function, just change debug_devm_mutex_init()
>> to __devm_mutex_init().
>
> I stuck to debug_* name because mutex-debug.c already exports a set
> of debug_ calls so...

Ah yes you are right I didn't see that. On the other hand all those
debug_mutex_* are used by kernel/locking/mutex.c.
Here we really don't want our new function to be called by anything else
than devm_mutex_init so by calling it __devm_mutex_init() you kind of
tie them together.

> Well it's not essential anyway. Here's the next try:

Looks good to me.

>
> diff --git a/include/linux/mutex.h b/include/linux/mutex.h
> index 67edc4ca2bee..537b5ea18ceb 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 +119,29 @@ 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)                    \
> +({                                                     \
> +       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
> --
> 2.25.1
>
>
>
>>> +
>>> +#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.
>>> +       */
>>
>> Don't know if it is because tabs are replaced by blanks in you email,
>> but the stars should be aligned
>
> Ack
>
>
> --
> Best regards
> George