Re: [PATCH v6 1/9] locking/mutex: introduce devm_mutex_init
On Thu, 14 Mar 2024 11:45:23 +0300 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 > Suggested by-by: Christophe Leroy Reviewed-by: Marek Behún
Re: [PATCH v5 02/10] locking/mutex: introduce devm_mutex_init
On Thu, 7 Mar 2024 08:39:46 -0500
Waiman Long wrote:
> On 3/7/24 04:56, Marek Behún wrote:
> > On Thu, Mar 07, 2024 at 05:40:26AM +0300, 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
> >> Signed-off-by: Christophe Leroy
> >> ---
> >> Hello Christophe. Hope you don't mind I put you SoB tag because you
> >> helped alot
> >> to make this patch happen.
> >>
> >> include/linux/mutex.h| 13 +
> >> kernel/locking/mutex-debug.c | 22 ++
> >> 2 files changed, 35 insertions(+)
> >>
> >> diff --git a/include/linux/mutex.h b/include/linux/mutex.h
> >> index f7611c092db7..9bcf72cb941a 100644
> >> --- a/include/linux/mutex.h
> >> +++ b/include/linux/mutex.h
> >> @@ -22,6 +22,8 @@
> >> #include
> >> #include
> >>
> >> +struct device;
> >> +
> >> #ifdef CONFIG_DEBUG_LOCK_ALLOC
> >> # define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
> >>, .dep_map = { \
> >> @@ -115,10 +117,21 @@ do {
> >> \
> >>
> >> #ifdef CONFIG_DEBUG_MUTEXES
> >>
> >> +int devm_mutex_init(struct device *dev, struct mutex *lock);
> >> void mutex_destroy(struct mutex *lock);
> >>
> >> #else
> >>
> >> +static inline int devm_mutex_init(struct device *dev, struct mutex *lock)
> >> +{
> >> + /*
> >> + * since mutex_destroy is nop actually there's no need to register it
> >> + * in devm subsystem.
> >> + */
> >> + mutex_init(lock);
> >> + return 0;
> >> +}
> >> +
> >> static inline void mutex_destroy(struct mutex *lock) {}
> >>
> >> #endif
> >> diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
> >> index bc8abb8549d2..c9efab1a8026 100644
> >> --- a/kernel/locking/mutex-debug.c
> >> +++ b/kernel/locking/mutex-debug.c
> >> @@ -19,6 +19,7 @@
> >> #include
> >> #include
> >> #include
> >> +#include
> >>
> >> #include "mutex.h"
> >>
> >> @@ -104,3 +105,24 @@ void mutex_destroy(struct mutex *lock)
> >> }
> >>
> >> EXPORT_SYMBOL_GPL(mutex_destroy);
> >> +
> >> +static void devm_mutex_release(void *res)
> >> +{
> >> + mutex_destroy(res);
> >> +}
> >> +
> >> +/**
> >> + * devm_mutex_init - Resource-managed mutex initialization
> >> + * @dev: Device which lifetime mutex is bound to
> >> + * @lock: Pointer to a mutex
> >> + *
> >> + * Initialize mutex which is automatically destroyed when the driver is
> >> detached.
> >> + *
> >> + * Returns: 0 on success or a negative error code on failure.
> >> + */
> >> +int devm_mutex_init(struct device *dev, struct mutex *lock)
> >> +{
> >> + mutex_init(lock);
> >> + return devm_add_action_or_reset(dev, devm_mutex_release, lock);
> >> +}
> >> +EXPORT_SYMBOL_GPL(devm_mutex_init);
> > Hi George,
> >
> > look at
> > https://lore.kernel.org/lkml/7013bf9e-2663-4613-ae61-61872e813...@redhat.com/
> > where Matthew and Hans explain that devm_mutex_init needs to be a macro
> > because of the static lockdep key.
> >
> > so this should be something like:
> >
> > static inline int __devm_mutex_init(struct device *dev, struct mutex *mutex,
> > const char *name,
> > struct lock_class_key *key)
> > {
> > __mutex_init(mutex, name, key);
> > return devm_add_action_or_reset(dev, devm_mutex_release, mutex);
> > }
> >
> > #define devm_mutex_init(dev, mutex) \
> > do {
Re: [PATCH v5 02/10] locking/mutex: introduce devm_mutex_init
On Thu, Mar 07, 2024 at 05:40:26AM +0300, 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
> Signed-off-by: Christophe Leroy
> ---
> Hello Christophe. Hope you don't mind I put you SoB tag because you helped
> alot
> to make this patch happen.
>
> include/linux/mutex.h| 13 +
> kernel/locking/mutex-debug.c | 22 ++
> 2 files changed, 35 insertions(+)
>
> diff --git a/include/linux/mutex.h b/include/linux/mutex.h
> index f7611c092db7..9bcf72cb941a 100644
> --- a/include/linux/mutex.h
> +++ b/include/linux/mutex.h
> @@ -22,6 +22,8 @@
> #include
> #include
>
> +struct device;
> +
> #ifdef CONFIG_DEBUG_LOCK_ALLOC
> # define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
> , .dep_map = { \
> @@ -115,10 +117,21 @@ do {
> \
>
> #ifdef CONFIG_DEBUG_MUTEXES
>
> +int devm_mutex_init(struct device *dev, struct mutex *lock);
> void mutex_destroy(struct mutex *lock);
>
> #else
>
> +static inline int devm_mutex_init(struct device *dev, struct mutex *lock)
> +{
> + /*
> + * since mutex_destroy is nop actually there's no need to register it
> + * in devm subsystem.
> + */
> + mutex_init(lock);
> + return 0;
> +}
> +
> static inline void mutex_destroy(struct mutex *lock) {}
>
> #endif
> diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
> index bc8abb8549d2..c9efab1a8026 100644
> --- a/kernel/locking/mutex-debug.c
> +++ b/kernel/locking/mutex-debug.c
> @@ -19,6 +19,7 @@
> #include
> #include
> #include
> +#include
>
> #include "mutex.h"
>
> @@ -104,3 +105,24 @@ void mutex_destroy(struct mutex *lock)
> }
>
> EXPORT_SYMBOL_GPL(mutex_destroy);
> +
> +static void devm_mutex_release(void *res)
> +{
> + mutex_destroy(res);
> +}
> +
> +/**
> + * devm_mutex_init - Resource-managed mutex initialization
> + * @dev: Device which lifetime mutex is bound to
> + * @lock:Pointer to a mutex
> + *
> + * Initialize mutex which is automatically destroyed when the driver is
> detached.
> + *
> + * Returns: 0 on success or a negative error code on failure.
> + */
> +int devm_mutex_init(struct device *dev, struct mutex *lock)
> +{
> + mutex_init(lock);
> + return devm_add_action_or_reset(dev, devm_mutex_release, lock);
> +}
> +EXPORT_SYMBOL_GPL(devm_mutex_init);
Hi George,
look at
https://lore.kernel.org/lkml/7013bf9e-2663-4613-ae61-61872e813...@redhat.com/
where Matthew and Hans explain that devm_mutex_init needs to be a macro
because of the static lockdep key.
so this should be something like:
static inline int __devm_mutex_init(struct device *dev, struct mutex *mutex,
const char *name,
struct lock_class_key *key)
{
__mutex_init(mutex, name, key);
return devm_add_action_or_reset(dev, devm_mutex_release, mutex);
}
#define devm_mutex_init(dev, mutex) \
do {\
static struct lock_class_key __key; \
\
__devm_mutex_init(dev, (mutex), #mutex, &__key);\
} while (0);
Marek
Re: [PATCH] powerpc: dts: turris1x.dts: Add channel labels for temperature sensor
On Fri, 30 Sep 2022 14:39:01 +0200
Pali Rohár wrote:
> Channel 0 of SA56004ED chip refers to internal SA56004ED chip sensor (chip
> itself is located on the board) and channel 1 of SA56004ED chip refers to
> external sensor which is connected to temperature diode of the P2020 CPU.
>
> Fixes: 54c15ec3b738 ("powerpc: dts: Add DTS file for CZ.NIC Turris 1.x
> routers")
> Signed-off-by: Pali Rohár
Reviewed-by: Marek Behún
Re: [PATCH 6/6] i2c: Make remove callback return void
g , Nicolas Ferre , Robert Foss , Krzysztof Kozlowski , Daniel Vetter , Alvin =?UTF-8?B?xaBpcHJhZ2E=?= , Luca Ceresoli , =?UTF-8?B?Sm9zw6kgRXhww7NzaXRv?= , Johannes Berg , Colin Ian King , Maximilian Luz , Helge Deller , Lucas Stach Errors-To: linuxppc-dev-bounces+archive=mail-archive@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, 28 Jun 2022 16:03:12 +0200 Uwe Kleine-König wrote: > From: Uwe Kleine-König > > The value returned by an i2c driver's remove function is mostly ignored. > (Only an error message is printed if the value is non-zero that the > error is ignored.) > > So change the prototype of the remove function to return no value. This > way driver authors are not tempted to assume that passing an error to > the upper layer is a good idea. All drivers are adapted accordingly. > There is no intended change of behaviour, all callbacks were prepared to > return 0 before. > > Signed-off-by: Uwe Kleine-König For > drivers/leds/leds-turris-omnia.c | 4 +--- Acked-by: Marek Behún
