lib/classifier: Use cmap.

Use cmap instead of hmap & hindex in classifier.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
Acked-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
lib/classifier: Simplify iteration with C99 declaration.

Hide the cursor from the classifier iteration users and move locking to
the iterators.  This will make following RCU changes simpler, as the call
sites of the iterators need not be changed at that point.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
lib/ovs-rcu: Export ovsrcu_synchronize().

A following patch will add the first external user.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
lib/classifier: Stylistic change.

Rename 'nbits' as 'n_bits' to be more consistent with other count-like
fields.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
lib/classifier: Use internal mutex.

Add an internal mutex to struct cls_classifier, and reorganize
classifier internal structures according to the user of each field,
marking the fields that need to be protected by the mutex.  This makes
locking requirements easier to track, and may make lookup more memory
efficient.

After this patch there is some double locking, as callers are taking
the fat-rwlock, and we take the mutex internally.  A following patch
will remove the classifier fat-rwlock, removing the (double) locking
overhead.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
lib/classifier: RCUify prefix trie code.

cls_set_prefix_fields() now synchronizes explicitly with the readers,
waiting them to finish using the old configuration before changing to
the new configuration.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
lib/classifier: Lockless lookups.

Now that all the relevant classifier structures use RCU and internal
mutual exclusion for modifications, we can remove the fat-rwlock and
thus make the classifier lookups lockless.

As the readers are operating concurrently with the writers, a
concurrent reader may or may not see a new rule being added by a
writer, depending on how the concurrent events overlap with each
other.  Overall, this is no different from the former locked behavior,
but there the visibility of the new rule only depended on the timing
of the locking functions.

A new rule is first added to the segment indices, so the readers may
find the rule in the indices before the rule is visible in the
subtables 'rules' map.  This may result in us losing the opportunity
to quit lookups earlier, resulting in sub-optimal wildcarding.  This
will be fixed by forthcoming revalidation always scheduled after flow
table changes.

Similar behavior may happen due to us removing the overlapping rule
(if any) from the indices only after the corresponding new rule has
been added.

The subtable's max priority is updated only after a rule is inserted
to the maps, so the concurrent readers may not see the rule, as the
updated priority ordered subtable list will only be visible after the
subtable's max priority is updated.

Similarly, the classifier's partitions are updated by the caller after
the rule is inserted to the maps, so the readers may keep skipping the
subtable until they see the updated partitions.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>