Merge branch 'mlxsw-spectrum_router-Increase-VRF-scale'

Jiri Pirko says:

====================
mlxsw: spectrum_router: Increase VRF scale

Ido says:

The purpose of this set is to increase the maximum number of supported VRF
devices on top of the Spectrum ASIC under different workloads.

This is achieved by sharing the same LPM tree across all the virtual
routers for a given L3 protocol (IPv4 / IPv6). The change is explained in
detail in the third patch. First two patches are small changes to make
review easier.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

@@ -320,19 +320,6 @@ struct mlxsw_sp_prefix_usage {
 #define mlxsw_sp_prefix_usage_for_each(prefix, prefix_usage) \
 	for_each_set_bit(prefix, (prefix_usage)->b, MLXSW_SP_PREFIX_COUNT)
 
-static bool
-mlxsw_sp_prefix_usage_subset(struct mlxsw_sp_prefix_usage *prefix_usage1,
-			     struct mlxsw_sp_prefix_usage *prefix_usage2)
-{
-	unsigned char prefix;
-
-	mlxsw_sp_prefix_usage_for_each(prefix, prefix_usage1) {
-		if (!test_bit(prefix, prefix_usage2->b))
-			return false;
-	}
-	return true;
-}
-
 static bool
 mlxsw_sp_prefix_usage_eq(struct mlxsw_sp_prefix_usage *prefix_usage1,
 			 struct mlxsw_sp_prefix_usage *prefix_usage2)
@@ -505,15 +492,15 @@ static int mlxsw_sp_lpm_tree_alloc(struct mlxsw_sp *mlxsw_sp,
 	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ralta), ralta_pl);
 }
 
-static int mlxsw_sp_lpm_tree_free(struct mlxsw_sp *mlxsw_sp,
-				  struct mlxsw_sp_lpm_tree *lpm_tree)
+static void mlxsw_sp_lpm_tree_free(struct mlxsw_sp *mlxsw_sp,
+				   struct mlxsw_sp_lpm_tree *lpm_tree)
 {
 	char ralta_pl[MLXSW_REG_RALTA_LEN];
 
 	mlxsw_reg_ralta_pack(ralta_pl, false,
 			     (enum mlxsw_reg_ralxx_protocol) lpm_tree->proto,
 			     lpm_tree->id);
-	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ralta), ralta_pl);
+	mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ralta), ralta_pl);
 }
 
 static int
@@ -569,10 +556,10 @@ mlxsw_sp_lpm_tree_create(struct mlxsw_sp *mlxsw_sp,
 	return ERR_PTR(err);
 }
 
-static int mlxsw_sp_lpm_tree_destroy(struct mlxsw_sp *mlxsw_sp,
-				     struct mlxsw_sp_lpm_tree *lpm_tree)
+static void mlxsw_sp_lpm_tree_destroy(struct mlxsw_sp *mlxsw_sp,
+				      struct mlxsw_sp_lpm_tree *lpm_tree)
 {
-	return mlxsw_sp_lpm_tree_free(mlxsw_sp, lpm_tree);
+	mlxsw_sp_lpm_tree_free(mlxsw_sp, lpm_tree);
 }
 
 static struct mlxsw_sp_lpm_tree *
@@ -589,24 +576,21 @@ mlxsw_sp_lpm_tree_get(struct mlxsw_sp *mlxsw_sp,
 		    lpm_tree->proto == proto &&
 		    mlxsw_sp_prefix_usage_eq(&lpm_tree->prefix_usage,
 					     prefix_usage))
-			goto inc_ref_count;
+			return lpm_tree;
 	}
-	lpm_tree = mlxsw_sp_lpm_tree_create(mlxsw_sp, prefix_usage,
-					    proto);
-	if (IS_ERR(lpm_tree))
-		return lpm_tree;
+	return mlxsw_sp_lpm_tree_create(mlxsw_sp, prefix_usage, proto);
+}
 
-inc_ref_count:
+static void mlxsw_sp_lpm_tree_hold(struct mlxsw_sp_lpm_tree *lpm_tree)
+{
 	lpm_tree->ref_count++;
-	return lpm_tree;
 }
 
-static int mlxsw_sp_lpm_tree_put(struct mlxsw_sp *mlxsw_sp,
-				 struct mlxsw_sp_lpm_tree *lpm_tree)
+static void mlxsw_sp_lpm_tree_put(struct mlxsw_sp *mlxsw_sp,
+				  struct mlxsw_sp_lpm_tree *lpm_tree)
 {
 	if (--lpm_tree->ref_count == 0)
-		return mlxsw_sp_lpm_tree_destroy(mlxsw_sp, lpm_tree);
-	return 0;
+		mlxsw_sp_lpm_tree_destroy(mlxsw_sp, lpm_tree);
 }
 
 #define MLXSW_SP_LPM_TREE_MIN 1 /* tree 0 is reserved */
@@ -660,13 +644,13 @@ static struct mlxsw_sp_vr *mlxsw_sp_vr_find_unused(struct mlxsw_sp *mlxsw_sp)
 }
 
 static int mlxsw_sp_vr_lpm_tree_bind(struct mlxsw_sp *mlxsw_sp,
-				     const struct mlxsw_sp_fib *fib)
+				     const struct mlxsw_sp_fib *fib, u8 tree_id)
 {
 	char raltb_pl[MLXSW_REG_RALTB_LEN];
 
 	mlxsw_reg_raltb_pack(raltb_pl, fib->vr->id,
 			     (enum mlxsw_reg_ralxx_protocol) fib->proto,
-			     fib->lpm_tree->id);
+			     tree_id);
 	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(raltb), raltb_pl);
 }
 
@@ -751,46 +735,6 @@ static void mlxsw_sp_vr_destroy(struct mlxsw_sp_vr *vr)
 	vr->fib4 = NULL;
 }
 
-static int
-mlxsw_sp_vr_lpm_tree_check(struct mlxsw_sp *mlxsw_sp, struct mlxsw_sp_fib *fib,
-			   struct mlxsw_sp_prefix_usage *req_prefix_usage)
-{
-	struct mlxsw_sp_lpm_tree *lpm_tree = fib->lpm_tree;
-	struct mlxsw_sp_lpm_tree *new_tree;
-	int err;
-
-	if (mlxsw_sp_prefix_usage_eq(req_prefix_usage, &lpm_tree->prefix_usage))
-		return 0;
-
-	new_tree = mlxsw_sp_lpm_tree_get(mlxsw_sp, req_prefix_usage,
-					 fib->proto);
-	if (IS_ERR(new_tree)) {
-		/* We failed to get a tree according to the required
-		 * prefix usage. However, the current tree might be still good
-		 * for us if our requirement is subset of the prefixes used
-		 * in the tree.
-		 */
-		if (mlxsw_sp_prefix_usage_subset(req_prefix_usage,
-						 &lpm_tree->prefix_usage))
-			return 0;
-		return PTR_ERR(new_tree);
-	}
-
-	/* Prevent packet loss by overwriting existing binding */
-	fib->lpm_tree = new_tree;
-	err = mlxsw_sp_vr_lpm_tree_bind(mlxsw_sp, fib);
-	if (err)
-		goto err_tree_bind;
-	mlxsw_sp_lpm_tree_put(mlxsw_sp, lpm_tree);
-
-	return 0;
-
-err_tree_bind:
-	fib->lpm_tree = lpm_tree;
-	mlxsw_sp_lpm_tree_put(mlxsw_sp, new_tree);
-	return err;
-}
-
 static struct mlxsw_sp_vr *mlxsw_sp_vr_get(struct mlxsw_sp *mlxsw_sp, u32 tb_id)
 {
 	struct mlxsw_sp_vr *vr;
@@ -809,6 +753,100 @@ static void mlxsw_sp_vr_put(struct mlxsw_sp_vr *vr)
 		mlxsw_sp_vr_destroy(vr);
 }
 
+static bool
+mlxsw_sp_vr_lpm_tree_should_replace(struct mlxsw_sp_vr *vr,
+				    enum mlxsw_sp_l3proto proto, u8 tree_id)
+{
+	struct mlxsw_sp_fib *fib = mlxsw_sp_vr_fib(vr, proto);
+
+	if (!mlxsw_sp_vr_is_used(vr))
+		return false;
+	if (fib->lpm_tree && fib->lpm_tree->id == tree_id)
+		return true;
+	return false;
+}
+
+static int mlxsw_sp_vr_lpm_tree_replace(struct mlxsw_sp *mlxsw_sp,
+					struct mlxsw_sp_fib *fib,
+					struct mlxsw_sp_lpm_tree *new_tree)
+{
+	struct mlxsw_sp_lpm_tree *old_tree = fib->lpm_tree;
+	int err;
+
+	err = mlxsw_sp_vr_lpm_tree_bind(mlxsw_sp, fib, new_tree->id);
+	if (err)
+		return err;
+	fib->lpm_tree = new_tree;
+	mlxsw_sp_lpm_tree_hold(new_tree);
+	mlxsw_sp_lpm_tree_put(mlxsw_sp, old_tree);
+	return 0;
+}
+
+static int mlxsw_sp_vrs_lpm_tree_replace(struct mlxsw_sp *mlxsw_sp,
+					 struct mlxsw_sp_fib *fib,
+					 struct mlxsw_sp_lpm_tree *new_tree)
+{
+	struct mlxsw_sp_lpm_tree *old_tree = fib->lpm_tree;
+	enum mlxsw_sp_l3proto proto = fib->proto;
+	u8 old_id, new_id = new_tree->id;
+	struct mlxsw_sp_vr *vr;
+	int i, err;
+
+	if (!old_tree)
+		goto no_replace;
+	old_id = old_tree->id;
+
+	for (i = 0; i < MLXSW_CORE_RES_GET(mlxsw_sp->core, MAX_VRS); i++) {
+		vr = &mlxsw_sp->router->vrs[i];
+		if (!mlxsw_sp_vr_lpm_tree_should_replace(vr, proto, old_id))
+			continue;
+		err = mlxsw_sp_vr_lpm_tree_replace(mlxsw_sp,
+						   mlxsw_sp_vr_fib(vr, proto),
+						   new_tree);
+		if (err)
+			goto err_tree_replace;
+	}
+
+	return 0;
+
+err_tree_replace:
+	for (i--; i >= 0; i--) {
+		if (!mlxsw_sp_vr_lpm_tree_should_replace(vr, proto, new_id))
+			continue;
+		mlxsw_sp_vr_lpm_tree_replace(mlxsw_sp,
+					     mlxsw_sp_vr_fib(vr, proto),
+					     old_tree);
+	}
+	return err;
+
+no_replace:
+	err = mlxsw_sp_vr_lpm_tree_bind(mlxsw_sp, fib, new_tree->id);
+	if (err)
+		return err;
+	fib->lpm_tree = new_tree;
+	mlxsw_sp_lpm_tree_hold(new_tree);
+	return 0;
+}
+
+static void
+mlxsw_sp_vrs_prefixes(struct mlxsw_sp *mlxsw_sp,
+		      enum mlxsw_sp_l3proto proto,
+		      struct mlxsw_sp_prefix_usage *req_prefix_usage)
+{
+	int i;
+
+	for (i = 0; i < MLXSW_CORE_RES_GET(mlxsw_sp->core, MAX_VRS); i++) {
+		struct mlxsw_sp_vr *vr = &mlxsw_sp->router->vrs[i];
+		struct mlxsw_sp_fib *fib = mlxsw_sp_vr_fib(vr, proto);
+		unsigned char prefix;
+
+		if (!mlxsw_sp_vr_is_used(vr))
+			continue;
+		mlxsw_sp_prefix_usage_for_each(prefix, &fib->prefix_usage)
+			mlxsw_sp_prefix_usage_set(req_prefix_usage, prefix);
+	}
+}
+
 static int mlxsw_sp_vrs_init(struct mlxsw_sp *mlxsw_sp)
 {
 	struct mlxsw_sp_vr *vr;
@@ -2587,6 +2625,67 @@ mlxsw_sp_fib_node_entry_is_first(const struct mlxsw_sp_fib_node *fib_node,
 				struct mlxsw_sp_fib_entry, list) == fib_entry;
 }
 
+static int mlxsw_sp_fib_lpm_tree_link(struct mlxsw_sp *mlxsw_sp,
+				      struct mlxsw_sp_fib *fib,
+				      struct mlxsw_sp_fib_node *fib_node)
+{
+	struct mlxsw_sp_prefix_usage req_prefix_usage = {{ 0 } };
+	struct mlxsw_sp_lpm_tree *lpm_tree;
+	int err;
+
+	/* Since the tree is shared between all virtual routers we must
+	 * make sure it contains all the required prefix lengths. This
+	 * can be computed by either adding the new prefix length to the
+	 * existing prefix usage of a bound tree, or by aggregating the
+	 * prefix lengths across all virtual routers and adding the new
+	 * one as well.
+	 */
+	if (fib->lpm_tree)
+		mlxsw_sp_prefix_usage_cpy(&req_prefix_usage,
+					  &fib->lpm_tree->prefix_usage);
+	else
+		mlxsw_sp_vrs_prefixes(mlxsw_sp, fib->proto, &req_prefix_usage);
+	mlxsw_sp_prefix_usage_set(&req_prefix_usage, fib_node->key.prefix_len);
+
+	lpm_tree = mlxsw_sp_lpm_tree_get(mlxsw_sp, &req_prefix_usage,
+					 fib->proto);
+	if (IS_ERR(lpm_tree))
+		return PTR_ERR(lpm_tree);
+
+	if (fib->lpm_tree && fib->lpm_tree->id == lpm_tree->id)
+		return 0;
+
+	err = mlxsw_sp_vrs_lpm_tree_replace(mlxsw_sp, fib, lpm_tree);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static void mlxsw_sp_fib_lpm_tree_unlink(struct mlxsw_sp *mlxsw_sp,
+					 struct mlxsw_sp_fib *fib)
+{
+	struct mlxsw_sp_prefix_usage req_prefix_usage = {{ 0 } };
+	struct mlxsw_sp_lpm_tree *lpm_tree;
+
+	/* Aggregate prefix lengths across all virtual routers to make
+	 * sure we only have used prefix lengths in the LPM tree.
+	 */
+	mlxsw_sp_vrs_prefixes(mlxsw_sp, fib->proto, &req_prefix_usage);
+	lpm_tree = mlxsw_sp_lpm_tree_get(mlxsw_sp, &req_prefix_usage,
+					 fib->proto);
+	if (IS_ERR(lpm_tree))
+		goto err_tree_get;
+	mlxsw_sp_vrs_lpm_tree_replace(mlxsw_sp, fib, lpm_tree);
+
+err_tree_get:
+	if (!mlxsw_sp_prefix_usage_none(&fib->prefix_usage))
+		return;
+	mlxsw_sp_vr_lpm_tree_unbind(mlxsw_sp, fib);
+	mlxsw_sp_lpm_tree_put(mlxsw_sp, fib->lpm_tree);
+	fib->lpm_tree = NULL;
+}
+
 static void mlxsw_sp_fib_node_prefix_inc(struct mlxsw_sp_fib_node *fib_node)
 {
 	unsigned char prefix_len = fib_node->key.prefix_len;
@@ -2609,8 +2708,6 @@ static int mlxsw_sp_fib_node_init(struct mlxsw_sp *mlxsw_sp,
 				  struct mlxsw_sp_fib_node *fib_node,
 				  struct mlxsw_sp_fib *fib)
 {
-	struct mlxsw_sp_prefix_usage req_prefix_usage;
-	struct mlxsw_sp_lpm_tree *lpm_tree;
 	int err;
 
 	err = mlxsw_sp_fib_node_insert(fib, fib_node);
@@ -2618,33 +2715,15 @@ static int mlxsw_sp_fib_node_init(struct mlxsw_sp *mlxsw_sp,
 		return err;
 	fib_node->fib = fib;
 
-	mlxsw_sp_prefix_usage_cpy(&req_prefix_usage, &fib->prefix_usage);
-	mlxsw_sp_prefix_usage_set(&req_prefix_usage, fib_node->key.prefix_len);
-
-	if (!mlxsw_sp_prefix_usage_none(&fib->prefix_usage)) {
-		err = mlxsw_sp_vr_lpm_tree_check(mlxsw_sp, fib,
-						 &req_prefix_usage);
-		if (err)
-			goto err_tree_check;
-	} else {
-		lpm_tree = mlxsw_sp_lpm_tree_get(mlxsw_sp, &req_prefix_usage,
-						 fib->proto);
-		if (IS_ERR(lpm_tree))
-			return PTR_ERR(lpm_tree);
-		fib->lpm_tree = lpm_tree;
-		err = mlxsw_sp_vr_lpm_tree_bind(mlxsw_sp, fib);
-		if (err)
-			goto err_tree_bind;
-	}
+	err = mlxsw_sp_fib_lpm_tree_link(mlxsw_sp, fib, fib_node);
+	if (err)
+		goto err_fib_lpm_tree_link;
 
 	mlxsw_sp_fib_node_prefix_inc(fib_node);
 
 	return 0;
 
-err_tree_bind:
-	fib->lpm_tree = NULL;
-	mlxsw_sp_lpm_tree_put(mlxsw_sp, lpm_tree);
-err_tree_check:
+err_fib_lpm_tree_link:
 	fib_node->fib = NULL;
 	mlxsw_sp_fib_node_remove(fib, fib_node);
 	return err;
@@ -2653,19 +2732,10 @@ static int mlxsw_sp_fib_node_init(struct mlxsw_sp *mlxsw_sp,
 static void mlxsw_sp_fib_node_fini(struct mlxsw_sp *mlxsw_sp,
 				   struct mlxsw_sp_fib_node *fib_node)
 {
-	struct mlxsw_sp_lpm_tree *lpm_tree = fib_node->fib->lpm_tree;
 	struct mlxsw_sp_fib *fib = fib_node->fib;
 
 	mlxsw_sp_fib_node_prefix_dec(fib_node);
-
-	if (mlxsw_sp_prefix_usage_none(&fib->prefix_usage)) {
-		mlxsw_sp_vr_lpm_tree_unbind(mlxsw_sp, fib);
-		fib->lpm_tree = NULL;
-		mlxsw_sp_lpm_tree_put(mlxsw_sp, lpm_tree);
-	} else {
-		mlxsw_sp_vr_lpm_tree_check(mlxsw_sp, fib, &fib->prefix_usage);
-	}
-
+	mlxsw_sp_fib_lpm_tree_unlink(mlxsw_sp, fib);
 	fib_node->fib = NULL;
 	mlxsw_sp_fib_node_remove(fib, fib_node);
 }