Messages in this thread | | | Date | Wed, 22 Mar 2023 10:13:37 +0100 | From | Greg KH <> | Subject | Re: [PATCH v2] staging: greybus: use inline function for macros |
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On Tue, Mar 21, 2023 at 08:34:56PM +0200, Menna Mahmoud wrote: > Convert `to_gbphy_dev` and `to_gbphy_driver` macros into a > static inline function. > > It is not great to have macros that use the `container_of` macro, > because from looking at the definition one cannot tell what type > it applies to.
Note, the compiler will tell you if you get this wrong, so this really is not an issue.
The container_of() macro is "special" in that it is very type safe and is very commonly used just as a #define to make it simpler and the compiler can just do the pointer math automatically without ever needing a function call to be involved.
> One can get the same benefit from an efficiency point of view > by making an inline function.
It's actually more efficient to be a macro, so this isn't correct.
But all of this is really moot, and I would normally just take this patch, but it's not correct:
> > Suggested-by: Julia Lawall <julia.lawall@inria.fr> > Signed-off-by: Menna Mahmoud <eng.mennamahmoud.mm@gmail.com> > --- > changes in v2: > -send patch as a single patch. > -edit the name of struct object. > -edit commit message. > --- > drivers/staging/greybus/gbphy.h | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/staging/greybus/gbphy.h b/drivers/staging/greybus/gbphy.h > index d4a225b76338..e7ba232bada1 100644 > --- a/drivers/staging/greybus/gbphy.h > +++ b/drivers/staging/greybus/gbphy.h > @@ -15,7 +15,10 @@ struct gbphy_device { > struct list_head list; > struct device dev; > }; > -#define to_gbphy_dev(d) container_of(d, struct gbphy_device, dev) > +static inline struct gbphy_device *to_gbphy_dev(const struct device *_dev) > +{ > + return container_of(_dev, struct gbphy_device, dev); > +}
You need a newline right before your new function to properly set it off.
> > static inline void *gb_gbphy_get_data(struct gbphy_device *gdev) > { > @@ -43,7 +46,10 @@ struct gbphy_driver { > > struct device_driver driver; > }; > -#define to_gbphy_driver(d) container_of(d, struct gbphy_driver, driver) > +static inline struct gbphy_driver *to_gbphy_driver(struct device_driver *drv) > +{ > + return container_of(drv, struct gbphy_driver, driver); > +}
I'm going to be a stickler here, and say this really should be using the new container_of_const() macro instead, and with that, you can NOT turn it into an inline function at all due to the fun use of Generic in that macro.
So I wouldn't recommend changing this macro at this time at all, sorry.
thanks,
greg k-h
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