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