[next-next PATCH v2 2/2] fbnic: Remove BMC routing rules when the BMC channel is disabled

@@ -55,6 +55,10 @@ enum {
 	FBNIC_FW_CAP_F_BMC_MACDA_SYNC,
 };
 
+#define FBNIC_FW_CAP_BMC_PENDING	\
+	(BIT(FBNIC_FW_CAP_F_BMC_TCAM_REINIT) |	\
+	 BIT(FBNIC_FW_CAP_F_BMC_MACDA_SYNC))
+
 struct fbnic_fw_cap {
 	unsigned long state;
 	struct {

@@ -143,9 +143,11 @@ void fbnic_bmc_rpc_all_multi_config(struct fbnic_dev *fbd,
 
 	/* If we are not enabling the rule just delete it. We will fall
 	 * back to the RSS rules that support the multicast addresses.
+	 * Delete in any live state, not just VALID, as ifdown demotes it to
+	 * UPDATE and a miss there leaves it to be rewritten to hardware.
 	 */
 	if (!fbnic_bmc_all_multi(fbd) || enable_host) {
-		if (act_tcam->state == FBNIC_TCAM_S_VALID)
+		if (act_tcam->state != FBNIC_TCAM_S_DISABLED)
 			act_tcam->state = FBNIC_TCAM_S_DELETE;
 		return;
 	}

@@ -234,10 +236,91 @@ void fbnic_bmc_rpc_init(struct fbnic_dev *fbd)
 	act_tcam->state = FBNIC_TCAM_S_UPDATE;
 }
 
+/**
+ * fbnic_bmc_rules_present - is the BMC currently programmed into the filters?
+ * @fbd: Pointer to fbnic device struct
+ *
+ * The BMC tag is only set while a BMC is present, so it doubles as the state.
+ *
+ * Return: true if any MACDA entry carries the BMC tag, false otherwise.
+ */
+static bool fbnic_bmc_rules_present(struct fbnic_dev *fbd)
+{
+	int idx;
+
+	for (idx = ARRAY_SIZE(fbd->mac_addr); idx--;) {
+		struct fbnic_mac_addr *mac_addr = &fbd->mac_addr[idx];
+
+		if (mac_addr->state == FBNIC_TCAM_S_DISABLED)
+			continue;
+
+		if (test_bit(FBNIC_MAC_ADDR_T_BMC, mac_addr->act_tcam))
+			return true;
+	}
+
+	return false;
+}
+
+/**
+ * fbnic_bmc_rpc_disable - remove the BMC MAC and action rules
+ * @fbd: Pointer to fbnic device struct
+ *
+ * Undo fbnic_bmc_rpc_init() when the BMC drops its NC-SI channel while the
+ * host interface stays up. Only marks shadow state; the caller's
+ * __fbnic_set_rx_mode() pushes it to hardware, so ordering here is moot.
+ */
+static void fbnic_bmc_rpc_disable(struct fbnic_dev *fbd)
+{
+	struct fbnic_act_tcam *act_tcam;
+	int idx;
+
+	/* Drop the BMC's claim; entries the host also uses survive */
+	for (idx = ARRAY_SIZE(fbd->mac_addr); idx--;) {
+		struct fbnic_mac_addr *mac_addr = &fbd->mac_addr[idx];
+
+		if (mac_addr->state == FBNIC_TCAM_S_DISABLED)
+			continue;
+
+		__fbnic_xc_unsync(mac_addr, FBNIC_MAC_ADDR_T_BMC);
+	}
+
+	/* Delete in any live state, not just VALID: init leaves it UPDATE and
+	 * ifdown demotes VALID to UPDATE. A miss leaks the rule for good, as
+	 * fbnic_bmc_rules_present() keys off the MACDA tag just cleared above.
+	 */
+	act_tcam = &fbd->act_tcam[FBNIC_RPC_ACT_TBL_BMC_OFFSET];
+	if (act_tcam->state != FBNIC_TCAM_S_DISABLED)
+		act_tcam->state = FBNIC_TCAM_S_DELETE;
+
+	/* fbnic_rss_reinit() only programs the host-unicast entries while a BMC
+	 * is present, so the reinit after this would leave them stale and valid
+	 * in hardware. Delete them to converge on the no-BMC layout.
+	 */
+	for (idx = 0; idx < FBNIC_RSS_EN_NUM_UNICAST; idx++) {
+		act_tcam = &fbd->act_tcam[FBNIC_RPC_ACT_TBL_RSS_OFFSET + idx];
+		if (act_tcam->state != FBNIC_TCAM_S_DISABLED)
+			act_tcam->state = FBNIC_TCAM_S_DELETE;
+	}
+}
+
 void fbnic_bmc_rpc_check(struct fbnic_dev *fbd)
 {
+	struct fbnic_net *fbn = netdev_priv(fbd->netdev);
 	int err;
 
+	/* Nothing to do unless the firmware raised one of the flags. Test
+	 * before taking the lock to keep it off the common path; one raised
+	 * after this is picked up on the next pass.
+	 */
+	if (!(READ_ONCE(fbd->fw_cap.state) & FBNIC_FW_CAP_BMC_PENDING))
+		return;
+
+	/* The rx mode work and the ethtool paths rewrite the MACDA and action
+	 * TCAM shadows under the instance lock, and this runs from the service
+	 * task under RTNL only, so the two do not exclude each other.
+	 */
+	netdev_lock(fbd->netdev);
+
 	/* Consume the flag before the state it advertises. The ordering
 	 * implied by test_and_clear_bit() pairs with the barrier in
 	 * fbnic_fw_parse_bmc_cap(), and claiming it atomically means a set

@@ -245,7 +328,15 @@ void fbnic_bmc_rpc_check(struct fbnic_dev *fbd)
 	 */
 	if (test_and_clear_bit(FBNIC_FW_CAP_F_BMC_TCAM_REINIT,
 			       &fbd->fw_cap.state)) {
-		fbnic_bmc_rpc_init(fbd);
+		if (!fbnic_bmc_present(fbd) && fbnic_bmc_rules_present(fbd))
+			fbnic_bmc_rpc_disable(fbd);
+		else
+			fbnic_bmc_rpc_init(fbd);
+
+		/* Neither path touches the RSS actions, which carry the mc/bc
+		 * copy to the BMC, so recompute them alongside.
+		 */
+		fbnic_rss_reinit(fbd, fbn);
 		netif_addr_lock_bh(fbd->netdev);
 		__fbnic_set_rx_mode(fbd, &fbd->netdev->uc, &fbd->netdev->mc);
 		netif_addr_unlock_bh(fbd->netdev);

@@ -258,6 +349,8 @@ void fbnic_bmc_rpc_check(struct fbnic_dev *fbd)
 			dev_warn(fbd->dev,
 				 "Writing MACDA table to FW failed, err: %d\n", err);
 	}
+
+	netdev_unlock(fbd->netdev);
 }
 
 #define FBNIC_ACT1_INIT(_l4, _udp, _ip, _v6)		\