Merge branch 'netvsc-bug-fixes-and-cleanups'

Stephen Hemminger says:

====================
netvsc: bug fixes and cleanups

These fix NAPI issues and bugs found during testing of shutdown
testing.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/hyperv/hyperv_net.h

@@ -686,7 +686,7 @@ struct net_device_context {
 	/* point back to our device context */
 	struct hv_device *device_ctx;
 	/* netvsc_device */
-	struct netvsc_device *nvdev;
+	struct netvsc_device __rcu *nvdev;
 	/* reconfigure work */
 	struct delayed_work dwork;
 	/* last reconfig time */
@@ -708,9 +708,6 @@ struct net_device_context {
 	u32 speed;
 	struct netvsc_ethtool_stats eth_stats;
 
-	/* the device is going away */
-	bool start_remove;
-
 	/* State to manage the associated VF interface. */
 	struct net_device __rcu *vf_netdev;
 
@@ -723,6 +720,7 @@ struct net_device_context {
 /* Per channel data */
 struct netvsc_channel {
 	struct vmbus_channel *channel;
+	const struct vmpacket_descriptor *desc;
 	struct napi_struct napi;
 	struct multi_send_data msd;
 	struct multi_recv_comp mrc;
@@ -763,8 +761,8 @@ struct netvsc_device {
 
 	u32 max_chn;
 	u32 num_chn;
-	spinlock_t sc_lock; /* Protects num_sc_offered variable */
-	u32 num_sc_offered;
+
+	refcount_t sc_offered;
 
 	/* Holds rndis device info */
 	void *extension;
@@ -779,6 +777,8 @@ struct netvsc_device {
 	atomic_t open_cnt;
 
 	struct netvsc_channel chan_table[VRSS_CHANNEL_MAX];
+
+	struct rcu_head rcu;
 };
 
 static inline struct netvsc_device *

drivers/net/hyperv/netvsc.c

@@ -80,8 +80,10 @@ static struct netvsc_device *alloc_net_device(void)
 	return net_device;
 }
 
-static void free_netvsc_device(struct netvsc_device *nvdev)
+static void free_netvsc_device(struct rcu_head *head)
 {
+	struct netvsc_device *nvdev
+		= container_of(head, struct netvsc_device, rcu);
 	int i;
 
 	for (i = 0; i < VRSS_CHANNEL_MAX; i++)
@@ -90,6 +92,10 @@ static void free_netvsc_device(struct netvsc_device *nvdev)
 	kfree(nvdev);
 }
 
+static void free_netvsc_device_rcu(struct netvsc_device *nvdev)
+{
+	call_rcu(&nvdev->rcu, free_netvsc_device);
+}
 
 static struct netvsc_device *get_outbound_net_device(struct hv_device *device)
 {
@@ -551,7 +557,7 @@ void netvsc_device_remove(struct hv_device *device)
 
 	netvsc_disconnect_vsp(device);
 
-	net_device_ctx->nvdev = NULL;
+	RCU_INIT_POINTER(net_device_ctx->nvdev, NULL);
 
 	/*
 	 * At this point, no one should be accessing net_device
@@ -566,7 +572,7 @@ void netvsc_device_remove(struct hv_device *device)
 		napi_disable(&net_device->chan_table[i].napi);
 
 	/* Release all resources */
-	free_netvsc_device(net_device);
+	free_netvsc_device_rcu(net_device);
 }
 
 #define RING_AVAIL_PERCENT_HIWATER 20
@@ -599,7 +605,6 @@ static void netvsc_send_tx_complete(struct netvsc_device *net_device,
 {
 	struct sk_buff *skb = (struct sk_buff *)(unsigned long)desc->trans_id;
 	struct net_device *ndev = hv_get_drvdata(device);
-	struct net_device_context *net_device_ctx = netdev_priv(ndev);
 	struct vmbus_channel *channel = device->channel;
 	u16 q_idx = 0;
 	int queue_sends;
@@ -633,7 +638,6 @@ static void netvsc_send_tx_complete(struct netvsc_device *net_device,
 		wake_up(&net_device->wait_drain);
 
 	if (netif_tx_queue_stopped(netdev_get_tx_queue(ndev, q_idx)) &&
-	    !net_device_ctx->start_remove &&
 	    (hv_ringbuf_avail_percent(&channel->outbound) > RING_AVAIL_PERCENT_HIWATER ||
 	     queue_sends < 1))
 		netif_tx_wake_queue(netdev_get_tx_queue(ndev, q_idx));
@@ -702,8 +706,7 @@ static u32 netvsc_copy_to_send_buf(struct netvsc_device *net_device,
 		packet->page_buf_cnt;
 
 	/* Add padding */
-	if (skb && skb->xmit_more && remain &&
-	    !packet->cp_partial) {
+	if (skb->xmit_more && remain && !packet->cp_partial) {
 		padding = net_device->pkt_align - remain;
 		rndis_msg->msg_len += padding;
 		packet->total_data_buflen += padding;
@@ -861,9 +864,7 @@ int netvsc_send(struct hv_device *device,
 	if (msdp->pkt)
 		msd_len = msdp->pkt->total_data_buflen;
 
-	try_batch = (skb != NULL) && msd_len > 0 && msdp->count <
-		    net_device->max_pkt;
-
+	try_batch =  msd_len > 0 && msdp->count < net_device->max_pkt;
 	if (try_batch && msd_len + pktlen + net_device->pkt_align <
 	    net_device->send_section_size) {
 		section_index = msdp->pkt->send_buf_index;
@@ -873,7 +874,7 @@ int netvsc_send(struct hv_device *device,
 		section_index = msdp->pkt->send_buf_index;
 		packet->cp_partial = true;
 
-	} else if ((skb != NULL) && pktlen + net_device->pkt_align <
+	} else if (pktlen + net_device->pkt_align <
 		   net_device->send_section_size) {
 		section_index = netvsc_get_next_send_section(net_device);
 		if (section_index != NETVSC_INVALID_INDEX) {
@@ -1173,7 +1174,6 @@ static int netvsc_process_raw_pkt(struct hv_device *device,
 				  struct vmbus_channel *channel,
 				  struct netvsc_device *net_device,
 				  struct net_device *ndev,
-				  u64 request_id,
 				  const struct vmpacket_descriptor *desc)
 {
 	struct net_device_context *net_device_ctx = netdev_priv(ndev);
@@ -1195,7 +1195,7 @@ static int netvsc_process_raw_pkt(struct hv_device *device,
 
 	default:
 		netdev_err(ndev, "unhandled packet type %d, tid %llx\n",
-			   desc->type, request_id);
+			   desc->type, desc->trans_id);
 		break;
 	}
 
@@ -1222,28 +1222,20 @@ int netvsc_poll(struct napi_struct *napi, int budget)
 	u16 q_idx = channel->offermsg.offer.sub_channel_index;
 	struct net_device *ndev = hv_get_drvdata(device);
 	struct netvsc_device *net_device = net_device_to_netvsc_device(ndev);
-	const struct vmpacket_descriptor *desc;
 	int work_done = 0;
 
-	desc = hv_pkt_iter_first(channel);
-	while (desc) {
-		int count;
-
-		count = netvsc_process_raw_pkt(device, channel, net_device,
-					       ndev, desc->trans_id, desc);
-		work_done += count;
-		desc = __hv_pkt_iter_next(channel, desc);
+	/* If starting a new interval */
+	if (!nvchan->desc)
+		nvchan->desc = hv_pkt_iter_first(channel);
 
-		/* If receive packet budget is exhausted, reschedule */
-		if (work_done >= budget) {
-			work_done = budget;
-			break;
-		}
+	while (nvchan->desc && work_done < budget) {
+		work_done += netvsc_process_raw_pkt(device, channel, net_device,
+						    ndev, nvchan->desc);
+		nvchan->desc = hv_pkt_iter_next(channel, nvchan->desc);
 	}
-	hv_pkt_iter_close(channel);
 
-	/* If budget was not exhausted and
-	 * not doing busy poll
+	/* If receive ring was exhausted
+	 * and not doing busy poll
 	 * then re-enable host interrupts
 	 *  and reschedule if ring is not empty.
 	 */
@@ -1253,7 +1245,9 @@ int netvsc_poll(struct napi_struct *napi, int budget)
 		napi_reschedule(napi);
 
 	netvsc_chk_recv_comp(net_device, channel, q_idx);
-	return work_done;
+
+	/* Driver may overshoot since multiple packets per descriptor */
+	return min(work_done, budget);
 }
 
 /* Call back when data is available in host ring buffer.
@@ -1263,10 +1257,12 @@ void netvsc_channel_cb(void *context)
 {
 	struct netvsc_channel *nvchan = context;
 
-	/* disable interupts from host */
-	hv_begin_read(&nvchan->channel->inbound);
+	if (napi_schedule_prep(&nvchan->napi)) {
+		/* disable interupts from host */
+		hv_begin_read(&nvchan->channel->inbound);
 
-	napi_schedule(&nvchan->napi);
+		__napi_schedule(&nvchan->napi);
+	}
 }
 
 /*
@@ -1325,9 +1321,7 @@ int netvsc_device_add(struct hv_device *device,
 	/* Writing nvdev pointer unlocks netvsc_send(), make sure chn_table is
 	 * populated.
 	 */
-	wmb();
-
-	net_device_ctx->nvdev = net_device;
+	rcu_assign_pointer(net_device_ctx->nvdev, net_device);
 
 	/* Connect with the NetVsp */
 	ret = netvsc_connect_vsp(device);
@@ -1346,7 +1340,7 @@ int netvsc_device_add(struct hv_device *device,
 	vmbus_close(device->channel);
 
 cleanup:
-	free_netvsc_device(net_device);
+	free_netvsc_device(&net_device->rcu);
 
 	return ret;
 }