Re: [PATCH] ipv4: avoid undefined behavior in do_ip_setsockopt()

On 11/11/12 5:02 PM, David Miller wrote:

This code is a fast bit test on purpose.  You're making the
code slower.

No, it's the opposite.  All modern compilers optimize switch cases
into a fast bit test.  The original "smarter" code, however, hinders
the compiler determining the mask for a fast bit test.  With this
patch, GCC is able to compute a better mask.  You can check the
assembly.

- xi