[PATCH v5 0/9] Improve the copy of task comm

[Alejandro Colomar]

Hi Yafang,

On Thu, Aug 08, 2024 at 10:49:17AM GMT, Yafang Shao wrote:
> > > Now, it might be a good idea to also verify that 'buf' is an actual
> > > array, and that this code doesn't do some silly "sizeof(ptr)" thing.
> >
> > I decided to use NITEMS() instead of sizeof() for that reason.
> > (NITEMS() is just our name for ARRAY_SIZE().)
> >
> >         $ grepc -h NITEMS .
> >         #define NITEMS(a)            (SIZEOF_ARRAY((a)) / sizeof((a)[0]))
> >
> > > We do have a helper for that, so we could do something like
> > >
> > >    #define get_task_comm(buf, tsk) \
> > >         strscpy_pad(buf, __must_be_array(buf)+sizeof(buf), (tsk)->comm)
> >
> > We have SIZEOF_ARRAY() for when you want the size of an array:
> >
> >         $ grepc -h SIZEOF_ARRAY .
> >         #define SIZEOF_ARRAY(a)      (sizeof(a) + must_be_array(a))
> 
> There is already a similar macro in Linux:
> 
>   /**
>    * ARRAY_SIZE - get the number of elements in array @arr
>    * @arr: array to be sized
>    */
>   #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) +
> __must_be_array(arr))

This is actually the same as our NITEMS(), not SIZEOF_ARRAY().

> will use it instead of the sizeof().

But yeah, indeed I think you should use ARRAY_SIZE() in
get_task_comm().  :)

> 
> Good point.
> I will avoid using the _pad().

Nice.  :)

Have a lovely day!
Alex

-- 
<https://www.alejandro-colomar.es/>
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