Re: [PATCH v4 02/28] printk: Add print format (%pra) for struct range

[Andy Shevchenko]

On Wed, Oct 09, 2024 at 03:30:14PM +0200, Rasmus Villemoes wrote:

...

> Rather than the struct assignments, I think it's easier to read if you
> just do
> 
>   struct range r;
> 
>   r.start = 0xc0ffee00ba5eba11;
>   r.end   = r.start;
>   ...
> 
>   r.start = 0xc0ffee;
>   r.end   = 0xba5eba11;
>   ...
> 
> which saves two lines per test and for the first one makes it more
> obvious that the start and end values are identical.

With DEFINE_RANGE() it will save even more lines!

..

> > +		if (buf < end)
> > +			*buf++ = '-';
> 
> No. Either all your callers pass a (probably stack-allocated) buffer
> which is guaranteed to be big enough, in which case you don't need the
> "if (buf < end)", or if some callers may "print" directly to the buffer
> passed to vsnprintf(), the buf++ must still be done unconditionally in
> order that vsnprintf(NULL, 0, ...) [used by fx kasprintf] can accurately
> determine how large the output string would be.

Ah, good catch, I would add...

> So, either
> 
>   *buf++ = '-'
> 
> or
> 
>   if (buf < end)
>     *buf = '-';
>   buf++;

...that we use rather ++buf in such cases, but it doesn't really matter.

> Please don't mix the two. 

-- 
With Best Regards,
Andy Shevchenko