Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 05847eb..32fe131 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -140,6 +140,20 @@
 	char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
 	struct xenvif *vif; /* Parent VIF */
 
+	/*
+	 * TX/RX common EOI handling.
+	 * When feature-split-event-channels = 0, interrupt handler sets
+	 * NETBK_COMMON_EOI, otherwise NETBK_RX_EOI and NETBK_TX_EOI are set
+	 * by the RX and TX interrupt handlers.
+	 * RX and TX handler threads will issue an EOI when either
+	 * NETBK_COMMON_EOI or their specific bits (NETBK_RX_EOI or
+	 * NETBK_TX_EOI) are set and they will reset those bits.
+	 */
+	atomic_t eoi_pending;
+#define NETBK_RX_EOI		0x01
+#define NETBK_TX_EOI		0x02
+#define NETBK_COMMON_EOI	0x04
+
 	/* Use NAPI for guest TX */
 	struct napi_struct napi;
 	/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
@@ -375,6 +389,7 @@
 
 irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data);
 
+bool xenvif_have_rx_work(struct xenvif_queue *queue, bool test_kthread);
 void xenvif_rx_action(struct xenvif_queue *queue);
 void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb);
 
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 103ed00..8090895 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -77,12 +77,28 @@
 		!vif->disabled;
 }
 
+static bool xenvif_handle_tx_interrupt(struct xenvif_queue *queue)
+{
+	bool rc;
+
+	rc = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
+	if (rc)
+		napi_schedule(&queue->napi);
+	return rc;
+}
+
 static irqreturn_t xenvif_tx_interrupt(int irq, void *dev_id)
 {
 	struct xenvif_queue *queue = dev_id;
+	int old;
 
-	if (RING_HAS_UNCONSUMED_REQUESTS(&queue->tx))
-		napi_schedule(&queue->napi);
+	old = atomic_fetch_or(NETBK_TX_EOI, &queue->eoi_pending);
+	WARN(old & NETBK_TX_EOI, "Interrupt while EOI pending\n");
+
+	if (!xenvif_handle_tx_interrupt(queue)) {
+		atomic_andnot(NETBK_TX_EOI, &queue->eoi_pending);
+		xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
+	}
 
 	return IRQ_HANDLED;
 }
@@ -116,19 +132,48 @@
 	return work_done;
 }
 
+static bool xenvif_handle_rx_interrupt(struct xenvif_queue *queue)
+{
+	bool rc;
+
+	rc = xenvif_have_rx_work(queue, false);
+	if (rc)
+		xenvif_kick_thread(queue);
+	return rc;
+}
+
 static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
 {
 	struct xenvif_queue *queue = dev_id;
+	int old;
 
-	xenvif_kick_thread(queue);
+	old = atomic_fetch_or(NETBK_RX_EOI, &queue->eoi_pending);
+	WARN(old & NETBK_RX_EOI, "Interrupt while EOI pending\n");
+
+	if (!xenvif_handle_rx_interrupt(queue)) {
+		atomic_andnot(NETBK_RX_EOI, &queue->eoi_pending);
+		xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
+	}
 
 	return IRQ_HANDLED;
 }
 
 irqreturn_t xenvif_interrupt(int irq, void *dev_id)
 {
-	xenvif_tx_interrupt(irq, dev_id);
-	xenvif_rx_interrupt(irq, dev_id);
+	struct xenvif_queue *queue = dev_id;
+	int old;
+	bool has_rx, has_tx;
+
+	old = atomic_fetch_or(NETBK_COMMON_EOI, &queue->eoi_pending);
+	WARN(old, "Interrupt while EOI pending\n");
+
+	has_tx = xenvif_handle_tx_interrupt(queue);
+	has_rx = xenvif_handle_rx_interrupt(queue);
+
+	if (!has_rx && !has_tx) {
+		atomic_andnot(NETBK_COMMON_EOI, &queue->eoi_pending);
+		xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
+	}
 
 	return IRQ_HANDLED;
 }
@@ -595,7 +640,7 @@
 	shared = (struct xen_netif_ctrl_sring *)addr;
 	BACK_RING_INIT(&vif->ctrl, shared, XEN_PAGE_SIZE);
 
-	err = bind_interdomain_evtchn_to_irq(vif->domid, evtchn);
+	err = bind_interdomain_evtchn_to_irq_lateeoi(vif->domid, evtchn);
 	if (err < 0)
 		goto err_unmap;
 
@@ -653,7 +698,7 @@
 
 	if (tx_evtchn == rx_evtchn) {
 		/* feature-split-event-channels == 0 */
-		err = bind_interdomain_evtchn_to_irqhandler(
+		err = bind_interdomain_evtchn_to_irqhandler_lateeoi(
 			queue->vif->domid, tx_evtchn, xenvif_interrupt, 0,
 			queue->name, queue);
 		if (err < 0)
@@ -664,7 +709,7 @@
 		/* feature-split-event-channels == 1 */
 		snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
 			 "%s-tx", queue->name);
-		err = bind_interdomain_evtchn_to_irqhandler(
+		err = bind_interdomain_evtchn_to_irqhandler_lateeoi(
 			queue->vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
 			queue->tx_irq_name, queue);
 		if (err < 0)
@@ -674,7 +719,7 @@
 
 		snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
 			 "%s-rx", queue->name);
-		err = bind_interdomain_evtchn_to_irqhandler(
+		err = bind_interdomain_evtchn_to_irqhandler_lateeoi(
 			queue->vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
 			queue->rx_irq_name, queue);
 		if (err < 0)
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 0020b2e..c213f2b 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -162,6 +162,10 @@
 
 	if (more_to_do)
 		napi_schedule(&queue->napi);
+	else if (atomic_fetch_andnot(NETBK_TX_EOI | NETBK_COMMON_EOI,
+				     &queue->eoi_pending) &
+		 (NETBK_TX_EOI | NETBK_COMMON_EOI))
+		xen_irq_lateeoi(queue->tx_irq, 0);
 }
 
 static void tx_add_credit(struct xenvif_queue *queue)
@@ -1336,7 +1340,15 @@
 				      NULL,
 				      queue->pages_to_map,
 				      nr_mops);
-		BUG_ON(ret);
+		if (ret) {
+			unsigned int i;
+
+			netdev_err(queue->vif->dev, "Map fail: nr %u ret %d\n",
+				   nr_mops, ret);
+			for (i = 0; i < nr_mops; ++i)
+				WARN_ON_ONCE(queue->tx_map_ops[i].status ==
+				             GNTST_okay);
+		}
 	}
 
 	work_done = xenvif_tx_submit(queue);
@@ -1622,9 +1634,14 @@
 irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data)
 {
 	struct xenvif *vif = data;
+	unsigned int eoi_flag = XEN_EOI_FLAG_SPURIOUS;
 
-	while (xenvif_ctrl_work_todo(vif))
+	while (xenvif_ctrl_work_todo(vif)) {
 		xenvif_ctrl_action(vif);
+		eoi_flag = 0;
+	}
+
+	xen_irq_lateeoi(irq, eoi_flag);
 
 	return IRQ_HANDLED;
 }
diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c
index ef58870..48e2006 100644
--- a/drivers/net/xen-netback/rx.c
+++ b/drivers/net/xen-netback/rx.c
@@ -38,10 +38,15 @@
 	RING_IDX prod, cons;
 	struct sk_buff *skb;
 	int needed;
+	unsigned long flags;
+
+	spin_lock_irqsave(&queue->rx_queue.lock, flags);
 
 	skb = skb_peek(&queue->rx_queue);
-	if (!skb)
+	if (!skb) {
+		spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
 		return false;
+	}
 
 	needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE);
 	if (skb_is_gso(skb))
@@ -49,6 +54,8 @@
 	if (skb->sw_hash)
 		needed++;
 
+	spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
+
 	do {
 		prod = queue->rx.sring->req_prod;
 		cons = queue->rx.req_cons;
@@ -490,13 +497,13 @@
 	return queue->stalled && prod - cons >= 1;
 }
 
-static bool xenvif_have_rx_work(struct xenvif_queue *queue)
+bool xenvif_have_rx_work(struct xenvif_queue *queue, bool test_kthread)
 {
 	return xenvif_rx_ring_slots_available(queue) ||
 		(queue->vif->stall_timeout &&
 		 (xenvif_rx_queue_stalled(queue) ||
 		  xenvif_rx_queue_ready(queue))) ||
-		kthread_should_stop() ||
+		(test_kthread && kthread_should_stop()) ||
 		queue->vif->disabled;
 }
 
@@ -527,15 +534,20 @@
 {
 	DEFINE_WAIT(wait);
 
-	if (xenvif_have_rx_work(queue))
+	if (xenvif_have_rx_work(queue, true))
 		return;
 
 	for (;;) {
 		long ret;
 
 		prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE);
-		if (xenvif_have_rx_work(queue))
+		if (xenvif_have_rx_work(queue, true))
 			break;
+		if (atomic_fetch_andnot(NETBK_RX_EOI | NETBK_COMMON_EOI,
+					&queue->eoi_pending) &
+		    (NETBK_RX_EOI | NETBK_COMMON_EOI))
+			xen_irq_lateeoi(queue->rx_irq, 0);
+
 		ret = schedule_timeout(xenvif_rx_queue_timeout(queue));
 		if (!ret)
 			break;
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index f533b73..416305e 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -713,12 +713,14 @@
 		return -ENOMEM;
 	snprintf(node, maxlen, "%s/rate", dev->nodename);
 	vif->credit_watch.node = node;
+	vif->credit_watch.will_handle = NULL;
 	vif->credit_watch.callback = xen_net_rate_changed;
 	err = register_xenbus_watch(&vif->credit_watch);
 	if (err) {
 		pr_err("Failed to set watcher %s\n", vif->credit_watch.node);
 		kfree(node);
 		vif->credit_watch.node = NULL;
+		vif->credit_watch.will_handle = NULL;
 		vif->credit_watch.callback = NULL;
 	}
 	return err;
@@ -765,6 +767,7 @@
 	snprintf(node, maxlen, "%s/request-multicast-control",
 		 dev->otherend);
 	vif->mcast_ctrl_watch.node = node;
+	vif->mcast_ctrl_watch.will_handle = NULL;
 	vif->mcast_ctrl_watch.callback = xen_mcast_ctrl_changed;
 	err = register_xenbus_watch(&vif->mcast_ctrl_watch);
 	if (err) {
@@ -772,6 +775,7 @@
 		       vif->mcast_ctrl_watch.node);
 		kfree(node);
 		vif->mcast_ctrl_watch.node = NULL;
+		vif->mcast_ctrl_watch.will_handle = NULL;
 		vif->mcast_ctrl_watch.callback = NULL;
 	}
 	return err;
@@ -975,11 +979,15 @@
 	xenvif_carrier_on(be->vif);
 
 	unregister_hotplug_status_watch(be);
-	err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
-				   hotplug_status_changed,
-				   "%s/%s", dev->nodename, "hotplug-status");
-	if (!err)
+	if (xenbus_exists(XBT_NIL, dev->nodename, "hotplug-status")) {
+		err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
+					   NULL, hotplug_status_changed,
+					   "%s/%s", dev->nodename,
+					   "hotplug-status");
+		if (err)
+			goto err;
 		be->have_hotplug_status_watch = 1;
+	}
 
 	netif_tx_wake_all_queues(be->vif->dev);