Re: [PATCH 01/12] x86_64: memset_user()

[Igor Stoppa]

On 21/12/2018 20:25, Matthew Wilcox wrote:
> On Fri, Dec 21, 2018 at 08:14:12PM +0200, Igor Stoppa wrote:
> > +unsigned long __memset_user(void __user *addr, int c, unsigned long size)
> > +{
> > +	long __d0;
> > +	unsigned long  pattern = 0;
> > +	int i;
> > +
> > +	for (i = 0; i < 8; i++)
> > +		pattern = (pattern << 8) | (0xFF & c);
>
> That's inefficient.
>
> 	pattern = (unsigned char)c;
> 	pattern |= pattern << 8;
> 	pattern |= pattern << 16;
> 	pattern |= pattern << 32;

ok, thank you

--
igor