Re: [PATCH v3] eal: Pointer alignment check improvements

[Bruce Richardson <bruce.richardson@intel.com>]

On Thu, Sep 22, 2022 at 10:54:38PM +0200, Morten Brørup wrote:
> > From: Bruce Richardson [mailto:bruce.richardson@intel.com]
> > Sent: Thursday, 22 September 2022 15.39
> > 
> > On Thu, Sep 22, 2022 at 03:27:30PM +0200, Morten Brørup wrote:
> > > Checking a const pointer for alignment would emit a warning about the
> > > const qualifier being discarded.
> > >
> > > No need to calculate the aligned pointer; just check the last bits of
> > the
> > > pointer.
> > >
> > > v3:
> > > - Make the uintptr_t const to avoid potential future warnings.
> > (Bruce)
> > > v2:
> > > - Remove compiler attribute ((const)) from function;
> > >   it was a coding style issue.
> > >
> > > Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
> > 
> > Acked-by: Bruce Richardson <bruce.richardson@intel.com>
> > 
> > Or perhaps it should be "Const-acked-by: ... " :-)
> 
> Unfortunately not as const as expected by both of us...
> 
> The v3 build fails at github [1] with:
> 
> ../lib/eal/include/rte_common.h: In function 'int rte_is_aligned(const void*, unsigned int)':
> ../lib/eal/include/rte_common.h:409:27: error: type qualifiers ignored on cast result type [-Werror=ignored-qualifiers]
>   409 |  return ((const uintptr_t)ptr & (align - 1)) == 0;
>       |                           ^~~
> 
> [1] http://mails.dpdk.org/archives/test-report/2022-September/308604.html
> 
> I don't understand what the problem is, so my solution is omitting the const, i.e. rolling back to v2, which doesn't fail building. Unless you can suggest a better solution, Bruce?
> 
> I have changed v2 status in Patchwork back to New and v3 to Superseded.
>
That is fine. I'll ack v2 so.