Przemek Kitszel wrote:
> > From: Jiri Pirko <jiri@xxxxxxxxxx>
> >
> > With introduction of __free() macro using cleanup infrastructure, it
> > will very likely become quite common to see following pattern:
> > type *var __free(kfree) = kzalloc(sizeof(*var), GFP_KERNEL);
> >
> > To follow the CLASS() flow from cleanup.h, introduce a simple macro
> > KZALLOC_FREE() to wrap this over and allow the same flow.
> >
> > Show an example usage in gpio-sim driver.
> >
> > Signed-off-by: Jiri Pirko <jiri@xxxxxxxxxx>
> > ---
> > drivers/gpio/gpio-sim.c | 3 +--
> > include/linux/slab.h | 3 +++
> > 2 files changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
> > index c4106e37e6db..997237b3d80c 100644
> > --- a/drivers/gpio/gpio-sim.c
> > +++ b/drivers/gpio/gpio-sim.c
> > @@ -1496,8 +1496,7 @@ gpio_sim_config_make_device_group(struct config_group *group, const char *name)
> > {
> > int id;
> >
> > - struct gpio_sim_device *dev __free(kfree) = kzalloc(sizeof(*dev),
> > - GFP_KERNEL);
> > + KZALLOC_FREE(struct gpio_sim_device *, dev, GFP_KERNEL);
> > if (!dev)
> > return ERR_PTR(-ENOMEM);
> >
> > diff --git a/include/linux/slab.h b/include/linux/slab.h
> > index b5f5ee8308d0..baee6acd58d3 100644
> > --- a/include/linux/slab.h
> > +++ b/include/linux/slab.h
> > @@ -711,6 +711,9 @@ static inline __alloc_size(1) void *kzalloc(size_t size, gfp_t flags)
> > return kmalloc(size, flags | __GFP_ZERO);
> > }
> >
> > +#define KZALLOC_FREE(_type, var, _gfp_t) \
> > + _type var __free(kfree) = kzalloc(sizeof(*var), _gfp_t)
> > +
>
> Nice, but I would rather see this wrapper in the cleanup.h file, that have all
> of the rest of related stuff.
>
> On top of that, I want to propose also a wrapper that is simpler in that it
> does not allocate but just assigns null, with that in mind `_FREE` part of your
> proposed name does not sound right.
No, do not hide assignments within macros
http://lore.kernel.org/r/CAHk-=whYxkfLVtBW_B-PgNqhKOAThTbfoH5CxtOTkwOB6VOt6w@xxxxxxxxxxxxxx
I.e. the amount of incremenal cleverness that include/linux/cleanup.h
will tolerate is low. Any helper should look like typical C.
