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 <[email protected]>
Suggested by-by: Christophe Leroy <[email protected]>
---
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
--
2.25.1
Le 14/03/2024 à 09:45, George Stark a écrit :
> 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 <[email protected]>
> Suggested by-by: Christophe Leroy <[email protected]>
s/Suggested by-by/Suggested-by:
Reviewed-by: Christophe Leroy <[email protected]>
> ---
> 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
On Thu, Mar 14, 2024 at 10:46 AM George Stark <[email protected]> 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()
Missing period at the end.
...
> Suggested by-by: Christophe Leroy <[email protected]>
Needs properly spelled tag.
..
> +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
mutex_destroy()
> + * no really need to register it in devm subsystem.
in the devm
> + */
> + return 0;
> +}
..
> @@ -19,6 +19,7 @@
> #include <linux/kallsyms.h>
> #include <linux/interrupt.h>
> #include <linux/debug_locks.h>
> +#include <linux/device.h>
Without seeing much context can't say if there is a better (more
ordered) place to squeeze a new header to. Please, check.
..
After addressing the above comments
Reviewed-by: Andy Shevchenko <[email protected]>
--
With Best Regards,
Andy Shevchenko
On Thu, 14 Mar 2024 11:45:23 +0300
George Stark <[email protected]> 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 <[email protected]>
> Suggested by-by: Christophe Leroy <[email protected]>
Reviewed-by: Marek Behún <[email protected]>
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 <[email protected]>
> Suggested by-by: Christophe Leroy <[email protected]>
> ---
> 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 <[email protected]>