[ovs-dev] [PATCH] lib/flow: Skip minimask value checks.

[Ben Pfaff]

On Fri, Dec 13, 2013 at 02:37:56PM -0800, Jarno Rajahalme wrote:
> We allow zero 'values' in a miniflow for it to have the same map
> as the corresponding minimask.  Minimasks themselves never have
> zero data values, though.  Document this and optimize the code
> accordingly.
> 
> Signed-off-by: Jarno Rajahalme <jrajahalme at nicira.com>

Indentation looks odd to me--did you use tabs instead of spaces?

Acked-by: Ben Pfaff <blp at nicira.com>

Here is an alternate concept for minimatch_hash_range() that might be
easier to understand.  I did not compile it or test it.

uint32_t
minimatch_hash_range(const struct minimatch *match, uint8_t start, uint8_t end,
                     uint32_t *basis)
{
    const uint32_t *p, *q;
    uint32_t hash = *basis;
    int n, i;

    n = count_1bits(miniflow_get_map_in_range(&match->mask.masks,
                                              start, end, &p));
    q = p + (match->flow.values - match->mask.masks.values);
    for (i = 0; i < n; i++) {
        hash = mhash_add(hash, p[i] & q[i]);
    }
    *basis = hash; /* Allow continuation from the unfinished value. */
    return mhash_finish(hash, n * 4);
}