net: prestera: manage matchall and flower priorities

matchall rules can be added only to chain 0 and their priorities have
limitations:
 - new matchall ingress rule's priority must be higher (lower value)
   than any existing flower rule;
 - new matchall egress rule's priority must be lower (higher value)
   than any existing flower rule.

The opposite works for flower rule adding:
 - new flower ingress rule's priority must be lower (higher value)
   than any existing matchall rule;
 - new flower egress rule's priority must be higher (lower value)
   than any existing matchall rule.

This is a hardware limitation and thus must be properly handled in
driver by reporting errors to the user when newly added rule has such a
priority that cannot be installed into the hardware.

To achieve this, the driver must maintain both min/max matchall
priorities for every flower block when user adds/deletes a matchall
rule, as well as both min/max flower priorities for chain 0 for every
adding/deletion of flower rules for chain 0.

Cc: Serhiy Boiko <serhiy.boiko@plvision.eu>
Signed-off-by: Maksym Glubokiy <maksym.glubokiy@plvision.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 48 insertions, 0 deletions

diff --git a/drivers/net/ethernet/marvell/prestera/prestera_flower.c b/drivers/net/ethernet/marvell/prestera/prestera_flower.c
index 19d3b55c578e..f38e8b3a543e 100644
--- a/drivers/net/ethernet/marvell/prestera/prestera_flower.c
+++ b/drivers/net/ethernet/marvell/prestera/prestera_flower.c
@@ -5,6 +5,7 @@
 #include "prestera_acl.h"
 #include "prestera_flow.h"
 #include "prestera_flower.h"
+#include "prestera_matchall.h"
 
 struct prestera_flower_template {
 	struct prestera_acl_ruleset *ruleset;
@@ -360,6 +361,49 @@ static int prestera_flower_parse(struct prestera_flow_block *block,
 					     f->common.extack);
 }
 
+static int prestera_flower_prio_check(struct prestera_flow_block *block,
+				      struct flow_cls_offload *f)
+{
+	u32 mall_prio_min;
+	u32 mall_prio_max;
+	int err;
+
+	err = prestera_mall_prio_get(block, &mall_prio_min, &mall_prio_max);
+	if (err == -ENOENT)
+		/* No matchall filters installed on this chain. */
+		return 0;
+
+	if (err) {
+		NL_SET_ERR_MSG(f->common.extack, "Failed to get matchall priorities");
+		return err;
+	}
+
+	if (f->common.prio <= mall_prio_max && block->ingress) {
+		NL_SET_ERR_MSG(f->common.extack,
+			       "Failed to add in front of existing matchall rules");
+		return -EOPNOTSUPP;
+	}
+	if (f->common.prio >= mall_prio_min && !block->ingress) {
+		NL_SET_ERR_MSG(f->common.extack, "Failed to add behind of existing matchall rules");
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+int prestera_flower_prio_get(struct prestera_flow_block *block, u32 chain_index,
+			     u32 *prio_min, u32 *prio_max)
+{
+	struct prestera_acl_ruleset *ruleset;
+
+	ruleset = prestera_acl_ruleset_lookup(block->sw->acl, block, chain_index);
+	if (IS_ERR(ruleset))
+		return PTR_ERR(ruleset);
+
+	prestera_acl_ruleset_prio_get(ruleset, prio_min, prio_max);
+	return 0;
+}
+
 int prestera_flower_replace(struct prestera_flow_block *block,
 			    struct flow_cls_offload *f)
 {
@@ -368,6 +412,10 @@ int prestera_flower_replace(struct prestera_flow_block *block,
 	struct prestera_acl_rule *rule;
 	int err;
 
+	err = prestera_flower_prio_check(block, f);
+	if (err)
+		return err;
+
 	ruleset = prestera_acl_ruleset_get(acl, block, f->common.chain_index);
 	if (IS_ERR(ruleset))
 		return PTR_ERR(ruleset);