[PATCH net-next 07/11] virtio_net: Use existing classifier if possible

[Daniel Jurgens]

Classifiers can be used by more than one rule. If there is an exisitng
classifier, use it instead of creating a new one.

Signed-off-by: Daniel Jurgens <dani...@nvidia.com>
Reviewed-by: Parav Pandit <pa...@nvidia.com>
Reviewed-by: Shahar Shitrit <shshit...@nvidia.com>
---
 drivers/net/virtio_net/virtio_net_ff.c | 39 ++++++++++++++++++--------
 1 file changed, 27 insertions(+), 12 deletions(-)

diff --git a/drivers/net/virtio_net/virtio_net_ff.c 
b/drivers/net/virtio_net/virtio_net_ff.c
index 473c2f169cfa..ebdac1fb49dd 100644
--- a/drivers/net/virtio_net/virtio_net_ff.c
+++ b/drivers/net/virtio_net/virtio_net_ff.c
@@ -17,6 +17,7 @@ struct virtnet_ethtool_rule {
 /* New fields must be added before the classifier struct */
 struct virtnet_classifier {
        size_t size;
+       refcount_t refcount;
        u32 id;
        struct virtio_net_resource_obj_ff_classifier classifier;
 };
@@ -105,11 +106,24 @@ static bool validate_mask(const struct virtnet_ff *ff,
        return false;
 }
 
-static int setup_classifier(struct virtnet_ff *ff, struct virtnet_classifier 
*c)
+static int setup_classifier(struct virtnet_ff *ff,
+                           struct virtnet_classifier **c)
 {
+       struct virtnet_classifier *tmp;
+       unsigned long i;
        int err;
 
-       err = xa_alloc(&ff->classifiers, &c->id, c,
+       xa_for_each(&ff->classifiers, i, tmp) {
+               if ((*c)->size == tmp->size &&
+                   !memcmp(&tmp->classifier, &(*c)->classifier, tmp->size)) {
+                       refcount_inc(&tmp->refcount);
+                       kfree(*c);
+                       *c = tmp;
+                       goto out;
+               }
+       }
+
+       err = xa_alloc(&ff->classifiers, &(*c)->id, *c,
                       XA_LIMIT(0, ff->ff_caps->classifiers_limit - 1),
                       GFP_KERNEL);
        if (err)
@@ -117,27 +131,28 @@ static int setup_classifier(struct virtnet_ff *ff, struct 
virtnet_classifier *c)
 
        err = virtio_device_object_create(ff->vdev,
                                          VIRTIO_NET_RESOURCE_OBJ_FF_CLASSIFIER,
-                                         c->id,
-                                         &c->classifier,
-                                         c->size);
+                                         (*c)->id,
+                                         &(*c)->classifier,
+                                         (*c)->size);
        if (err)
                goto err_xarray;
 
+       refcount_set(&(*c)->refcount, 1);
+out:
        return 0;
 
 err_xarray:
-       xa_erase(&ff->classifiers, c->id);
+       xa_erase(&ff->classifiers, (*c)->id);
 
        return err;
 }
 
-static void destroy_classifier(struct virtnet_ff *ff,
-                              u32 classifier_id)
+static void try_destroy_classifier(struct virtnet_ff *ff, u32 classifier_id)
 {
        struct virtnet_classifier *c;
 
        c = xa_load(&ff->classifiers, classifier_id);
-       if (c) {
+       if (c && refcount_dec_and_test(&c->refcount)) {
                virtio_device_object_destroy(ff->vdev,
                                             
VIRTIO_NET_RESOURCE_OBJ_FF_CLASSIFIER,
                                             c->id);
@@ -157,7 +172,7 @@ static void destroy_ethtool_rule(struct virtnet_ff *ff,
                                     eth_rule->flow_spec.location);
 
        xa_erase(&ff->ethtool.rules, eth_rule->flow_spec.location);
-       destroy_classifier(ff, eth_rule->classifier_id);
+       try_destroy_classifier(ff, eth_rule->classifier_id);
        kfree(eth_rule);
 }
 
@@ -338,13 +353,13 @@ static int build_and_insert(struct virtnet_ff *ff,
        if (err)
                goto err_key;
 
-       err = setup_classifier(ff, c);
+       err = setup_classifier(ff, &c);
        if (err)
                goto err_classifier;
 
        err = insert_rule(ff, eth_rule, c->id, key, key_size);
        if (err) {
-               destroy_classifier(ff, c->id);
+               try_destroy_classifier(ff, c->id);
                goto err_key;
        }
 
-- 
2.50.1