nfp: fix schedule in atomic context when sync mc address

The callback `.ndo_set_rx_mode` is called in atomic context, sleep
is not allowed in the implementation. Now use workqueue mechanism
to avoid this issue.

Fixes: de62486 ("nfp: add support for multicast filter")
Signed-off-by: Yinjun Zhang <yinjun.zhang@corigine.com>
Reviewed-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20221220152100.1042774-1-simon.horman@corigine.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Yinjun Zhang

drivers/net/ethernet/netronome/nfp/nfp_net.h

@@ -617,6 +617,9 @@ struct nfp_net_dp {
  * @vnic_no_name:	For non-port PF vNIC make ndo_get_phys_port_name return
  *			-EOPNOTSUPP to keep backwards compatibility (set by app)
  * @port:		Pointer to nfp_port structure if vNIC is a port
+ * @mc_lock:		Protect mc_addrs list
+ * @mc_addrs:		List of mc addrs to add/del to HW
+ * @mc_work:		Work to update mc addrs
  * @app_priv:		APP private data for this vNIC
  */
 struct nfp_net {
@@ -718,6 +721,10 @@ struct nfp_net {
 
 	struct nfp_port *port;
 
+	spinlock_t mc_lock;
+	struct list_head mc_addrs;
+	struct work_struct mc_work;
+
 	void *app_priv;
 };
 

drivers/net/ethernet/netronome/nfp/nfp_net_common.c

@@ -1334,9 +1334,14 @@ int nfp_ctrl_open(struct nfp_net *nn)
 	return err;
 }
 
-static int nfp_net_mc_cfg(struct net_device *netdev, const unsigned char *addr, const u32 cmd)
+struct nfp_mc_addr_entry {
+	u8 addr[ETH_ALEN];
+	u32 cmd;
+	struct list_head list;
+};
+
+static int nfp_net_mc_cfg(struct nfp_net *nn, const unsigned char *addr, const u32 cmd)
 {
-	struct nfp_net *nn = netdev_priv(netdev);
 	int ret;
 
 	ret = nfp_net_mbox_lock(nn, NFP_NET_CFG_MULTICAST_SZ);
@@ -1351,6 +1356,25 @@ static int nfp_net_mc_cfg(struct net_device *netdev, const unsigned char *addr,
 	return nfp_net_mbox_reconfig_and_unlock(nn, cmd);
 }
 
+static int nfp_net_mc_prep(struct nfp_net *nn, const unsigned char *addr, const u32 cmd)
+{
+	struct nfp_mc_addr_entry *entry;
+
+	entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
+	if (!entry)
+		return -ENOMEM;
+
+	ether_addr_copy(entry->addr, addr);
+	entry->cmd = cmd;
+	spin_lock_bh(&nn->mc_lock);
+	list_add_tail(&entry->list, &nn->mc_addrs);
+	spin_unlock_bh(&nn->mc_lock);
+
+	schedule_work(&nn->mc_work);
+
+	return 0;
+}
+
 static int nfp_net_mc_sync(struct net_device *netdev, const unsigned char *addr)
 {
 	struct nfp_net *nn = netdev_priv(netdev);
@@ -1361,12 +1385,35 @@ static int nfp_net_mc_sync(struct net_device *netdev, const unsigned char *addr)
 		return -EINVAL;
 	}
 
-	return nfp_net_mc_cfg(netdev, addr, NFP_NET_CFG_MBOX_CMD_MULTICAST_ADD);
+	return nfp_net_mc_prep(nn, addr, NFP_NET_CFG_MBOX_CMD_MULTICAST_ADD);
 }
 
 static int nfp_net_mc_unsync(struct net_device *netdev, const unsigned char *addr)
 {
-	return nfp_net_mc_cfg(netdev, addr, NFP_NET_CFG_MBOX_CMD_MULTICAST_DEL);
+	struct nfp_net *nn = netdev_priv(netdev);
+
+	return nfp_net_mc_prep(nn, addr, NFP_NET_CFG_MBOX_CMD_MULTICAST_DEL);
+}
+
+static void nfp_net_mc_addr_config(struct work_struct *work)
+{
+	struct nfp_net *nn = container_of(work, struct nfp_net, mc_work);
+	struct nfp_mc_addr_entry *entry, *tmp;
+	struct list_head tmp_list;
+
+	INIT_LIST_HEAD(&tmp_list);
+
+	spin_lock_bh(&nn->mc_lock);
+	list_splice_init(&nn->mc_addrs, &tmp_list);
+	spin_unlock_bh(&nn->mc_lock);
+
+	list_for_each_entry_safe(entry, tmp, &tmp_list, list) {
+		if (nfp_net_mc_cfg(nn, entry->addr, entry->cmd))
+			nn_err(nn, "Config mc address to HW failed.\n");
+
+		list_del(&entry->list);
+		kfree(entry);
+	}
 }
 
 static void nfp_net_set_rx_mode(struct net_device *netdev)
@@ -2633,6 +2680,11 @@ int nfp_net_init(struct nfp_net *nn)
 
 	if (!nn->dp.netdev)
 		return 0;
+
+	spin_lock_init(&nn->mc_lock);
+	INIT_LIST_HEAD(&nn->mc_addrs);
+	INIT_WORK(&nn->mc_work, nfp_net_mc_addr_config);
+
 	return register_netdev(nn->dp.netdev);
 
 err_clean_mbox:
@@ -2652,5 +2704,6 @@ void nfp_net_clean(struct nfp_net *nn)
 	unregister_netdev(nn->dp.netdev);
 	nfp_net_ipsec_clean(nn);
 	nfp_ccm_mbox_clean(nn);
+	flush_work(&nn->mc_work);
 	nfp_net_reconfig_wait_posted(nn);
 }