bnx2x: Fix vlan credit issues for VFs

Starting with commit 2dc33bbc "bnx2x: Remove the sriov VFOP mechanism",
the bnx2x started enforcing vlan credits for all vlan configurations.
This exposed 2 issues:
  - Vlan credits are not returned once a VF is removed; this causes a leak
    of credits, and eventually will lead to VFs with no vlan credits.
  - A vlan credit must be set aside for the Hypervisor to use, and should
    not be visible to the VF.

Although linux VFs at the moment do not support vlan configuration [from the
VF side] which causes them to be resilient to this sort of issue, Windows VF
over linux hypervisors might fail to load as the vlan credits become depleted.
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: Ariel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.c

@@ -427,7 +427,9 @@ static int bnx2x_vf_mac_vlan_config(struct bnx2x *bp,
 	if (filter->add && filter->type == BNX2X_VF_FILTER_VLAN &&
 	    (atomic_read(&bnx2x_vfq(vf, qid, vlan_count)) >=
 	     vf_vlan_rules_cnt(vf))) {
-		BNX2X_ERR("No credits for vlan\n");
+		BNX2X_ERR("No credits for vlan [%d >= %d]\n",
+			  atomic_read(&bnx2x_vfq(vf, qid, vlan_count)),
+			  vf_vlan_rules_cnt(vf));
 		return -ENOMEM;
 	}
 
@@ -837,6 +839,29 @@ int bnx2x_vf_flr_clnup_epilog(struct bnx2x *bp, u8 abs_vfid)
 	return 0;
 }
 
+static void bnx2x_iov_re_set_vlan_filters(struct bnx2x *bp,
+					  struct bnx2x_virtf *vf,
+					  int new)
+{
+	int num = vf_vlan_rules_cnt(vf);
+	int diff = new - num;
+	bool rc = true;
+
+	DP(BNX2X_MSG_IOV, "vf[%d] - %d vlan filter credits [previously %d]\n",
+	   vf->abs_vfid, new, num);
+
+	if (diff > 0)
+		rc = bp->vlans_pool.get(&bp->vlans_pool, diff);
+	else if (diff < 0)
+		rc = bp->vlans_pool.put(&bp->vlans_pool, -diff);
+
+	if (rc)
+		vf_vlan_rules_cnt(vf) = new;
+	else
+		DP(BNX2X_MSG_IOV, "vf[%d] - Failed to configure vlan filter credits change\n",
+		   vf->abs_vfid);
+}
+
 /* must be called after the number of PF queues and the number of VFs are
  * both known
  */
@@ -854,9 +879,11 @@ bnx2x_iov_static_resc(struct bnx2x *bp, struct bnx2x_virtf *vf)
 	resc->num_mac_filters = 1;
 
 	/* divvy up vlan rules */
+	bnx2x_iov_re_set_vlan_filters(bp, vf, 0);
 	vlan_count = bp->vlans_pool.check(&bp->vlans_pool);
 	vlan_count = 1 << ilog2(vlan_count);
-	resc->num_vlan_filters = vlan_count / BNX2X_NR_VIRTFN(bp);
+	bnx2x_iov_re_set_vlan_filters(bp, vf,
+				      vlan_count / BNX2X_NR_VIRTFN(bp));
 
 	/* no real limitation */
 	resc->num_mc_filters = 0;
@@ -1478,10 +1505,6 @@ int bnx2x_iov_nic_init(struct bnx2x *bp)
 		bnx2x_iov_static_resc(bp, vf);
 
 		/* queues are initialized during VF-ACQUIRE */
-
-		/* reserve the vf vlan credit */
-		bp->vlans_pool.get(&bp->vlans_pool, vf_vlan_rules_cnt(vf));
-
 		vf->filter_state = 0;
 		vf->sp_cl_id = bnx2x_fp(bp, 0, cl_id);
 
@@ -1912,11 +1935,12 @@ int bnx2x_vf_chk_avail_resc(struct bnx2x *bp, struct bnx2x_virtf *vf,
 	u8 rxq_cnt = vf_rxq_count(vf) ? : bnx2x_vf_max_queue_cnt(bp, vf);
 	u8 txq_cnt = vf_txq_count(vf) ? : bnx2x_vf_max_queue_cnt(bp, vf);
 
+	/* Save a vlan filter for the Hypervisor */
 	return ((req_resc->num_rxqs <= rxq_cnt) &&
 		(req_resc->num_txqs <= txq_cnt) &&
 		(req_resc->num_sbs <= vf_sb_count(vf))   &&
 		(req_resc->num_mac_filters <= vf_mac_rules_cnt(vf)) &&
-		(req_resc->num_vlan_filters <= vf_vlan_rules_cnt(vf)));
+		(req_resc->num_vlan_filters <= vf_vlan_rules_visible_cnt(vf)));
 }
 
 /* CORE VF API */
@@ -1972,14 +1996,14 @@ int bnx2x_vf_acquire(struct bnx2x *bp, struct bnx2x_virtf *vf,
 	vf_txq_count(vf) = resc->num_txqs ? : bnx2x_vf_max_queue_cnt(bp, vf);
 	if (resc->num_mac_filters)
 		vf_mac_rules_cnt(vf) = resc->num_mac_filters;
-	if (resc->num_vlan_filters)
-		vf_vlan_rules_cnt(vf) = resc->num_vlan_filters;
+	/* Add an additional vlan filter credit for the hypervisor */
+	bnx2x_iov_re_set_vlan_filters(bp, vf, resc->num_vlan_filters + 1);
 
 	DP(BNX2X_MSG_IOV,
 	   "Fulfilling vf request: sb count %d, tx_count %d, rx_count %d, mac_rules_count %d, vlan_rules_count %d\n",
 	   vf_sb_count(vf), vf_rxq_count(vf),
 	   vf_txq_count(vf), vf_mac_rules_cnt(vf),
-	   vf_vlan_rules_cnt(vf));
+	   vf_vlan_rules_visible_cnt(vf));
 
 	/* Initialize the queues */
 	if (!vf->vfqs) {

drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.h

@@ -159,6 +159,8 @@ struct bnx2x_virtf {
 #define vf_mac_rules_cnt(vf)		((vf)->alloc_resc.num_mac_filters)
 #define vf_vlan_rules_cnt(vf)		((vf)->alloc_resc.num_vlan_filters)
 #define vf_mc_rules_cnt(vf)		((vf)->alloc_resc.num_mc_filters)
+	/* Hide a single vlan filter credit for the hypervisor */
+#define vf_vlan_rules_visible_cnt(vf)	(vf_vlan_rules_cnt(vf) - 1)
 
 	u8 sb_count;	/* actual number of SBs */
 	u8 igu_base_id;	/* base igu status block id */

drivers/net/ethernet/broadcom/bnx2x/bnx2x_vfpf.c

@@ -1163,7 +1163,7 @@ static void bnx2x_vf_mbx_acquire_resp(struct bnx2x *bp, struct bnx2x_virtf *vf,
 			bnx2x_vf_max_queue_cnt(bp, vf);
 		resc->num_sbs = vf_sb_count(vf);
 		resc->num_mac_filters = vf_mac_rules_cnt(vf);
-		resc->num_vlan_filters = vf_vlan_rules_cnt(vf);
+		resc->num_vlan_filters = vf_vlan_rules_visible_cnt(vf);
 		resc->num_mc_filters = 0;
 
 		if (status == PFVF_STATUS_SUCCESS) {