[PATCH net-next v2 1/2] net: ibmveth: make ibmveth use WARN_ON instead of BUG_ON

[Dave Marquardt <davemarq@linux.ibm.com>]

Replaced BUG_ON calls with WARN_ON calls with error handling, with
calls to a new ibmveth_reset routine, which resets the device. Removed
conflicting and unneeded forward declaration.

Signed-off-by: Dave Marquardt <davemarq@linux.ibm.com>
---
 drivers/net/ethernet/ibm/ibmveth.c | 116 ++++++++++++++++++++++++-----
 drivers/net/ethernet/ibm/ibmveth.h |  65 ++++++++--------
 2 files changed, 130 insertions(+), 51 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index 04192190beba..e005caf5874d 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -39,8 +39,6 @@
 #include "ibmveth.h"
 
 static irqreturn_t ibmveth_interrupt(int irq, void *dev_instance);
-static void ibmveth_rxq_harvest_buffer(struct ibmveth_adapter *adapter,
-				       bool reuse);
 static unsigned long ibmveth_get_desired_dma(struct vio_dev *vdev);
 
 static struct kobj_type ktype_veth_pool;
@@ -231,7 +229,10 @@ static void ibmveth_replenish_buffer_pool(struct ibmveth_adapter *adapter,
 		index = pool->free_map[free_index];
 		skb = NULL;
 
-		BUG_ON(index == IBM_VETH_INVALID_MAP);
+		if (WARN_ON(index == IBM_VETH_INVALID_MAP)) {
+			schedule_work(&adapter->work);
+			goto bad_index_failure;
+		}
 
 		/* are we allocating a new buffer or recycling an old one */
 		if (pool->skbuff[index])
@@ -300,6 +301,7 @@ static void ibmveth_replenish_buffer_pool(struct ibmveth_adapter *adapter,
 		                 DMA_FROM_DEVICE);
 	dev_kfree_skb_any(pool->skbuff[index]);
 	pool->skbuff[index] = NULL;
+bad_index_failure:
 	adapter->replenish_add_buff_failure++;
 
 	mb();
@@ -370,20 +372,36 @@ static void ibmveth_free_buffer_pool(struct ibmveth_adapter *adapter,
 	}
 }
 
-/* remove a buffer from a pool */
-static void ibmveth_remove_buffer_from_pool(struct ibmveth_adapter *adapter,
-					    u64 correlator, bool reuse)
+/**
+ * ibmveth_remove_buffer_from_pool - remove a buffer from a pool
+ * @adapter: adapter instance
+ * @correlator: identifies pool and index
+ * @reuse: whether to reuse buffer
+ *
+ * Return:
+ * * %0       - success
+ * * %-EINVAL - correlator maps to pool or index out of range
+ * * %-EFAULT - pool and index map to null skb
+ */
+static int ibmveth_remove_buffer_from_pool(struct ibmveth_adapter *adapter,
+					   u64 correlator, bool reuse)
 {
 	unsigned int pool  = correlator >> 32;
 	unsigned int index = correlator & 0xffffffffUL;
 	unsigned int free_index;
 	struct sk_buff *skb;
 
-	BUG_ON(pool >= IBMVETH_NUM_BUFF_POOLS);
-	BUG_ON(index >= adapter->rx_buff_pool[pool].size);
+	if (WARN_ON(pool >= IBMVETH_NUM_BUFF_POOLS) ||
+	    WARN_ON(index >= adapter->rx_buff_pool[pool].size)) {
+		schedule_work(&adapter->work);
+		return -EINVAL;
+	}
 
 	skb = adapter->rx_buff_pool[pool].skbuff[index];
-	BUG_ON(skb == NULL);
+	if (WARN_ON(!skb)) {
+		schedule_work(&adapter->work);
+		return -EFAULT;
+	}
 
 	/* if we are going to reuse the buffer then keep the pointers around
 	 * but mark index as available. replenish will see the skb pointer and
@@ -411,6 +429,8 @@ static void ibmveth_remove_buffer_from_pool(struct ibmveth_adapter *adapter,
 	mb();
 
 	atomic_dec(&(adapter->rx_buff_pool[pool].available));
+
+	return 0;
 }
 
 /* get the current buffer on the rx queue */
@@ -420,24 +440,44 @@ static inline struct sk_buff *ibmveth_rxq_get_buffer(struct ibmveth_adapter *ada
 	unsigned int pool = correlator >> 32;
 	unsigned int index = correlator & 0xffffffffUL;
 
-	BUG_ON(pool >= IBMVETH_NUM_BUFF_POOLS);
-	BUG_ON(index >= adapter->rx_buff_pool[pool].size);
+	if (WARN_ON(pool >= IBMVETH_NUM_BUFF_POOLS) ||
+	    WARN_ON(index >= adapter->rx_buff_pool[pool].size)) {
+		schedule_work(&adapter->work);
+		return NULL;
+	}
 
 	return adapter->rx_buff_pool[pool].skbuff[index];
 }
 
-static void ibmveth_rxq_harvest_buffer(struct ibmveth_adapter *adapter,
-				       bool reuse)
+/**
+ * ibmveth_rxq_harvest_buffer - Harvest buffer from pool
+ *
+ * @adapter - pointer to adapter
+ * @reuse   - whether to reuse buffer
+ *
+ * Context: called from ibmveth_poll
+ *
+ * Return:
+ * * %0    - success
+ * * other - non-zero return from ibmveth_remove_buffer_from_pool
+ */
+static int ibmveth_rxq_harvest_buffer(struct ibmveth_adapter *adapter,
+				      bool reuse)
 {
 	u64 cor;
+	int rc;
 
 	cor = adapter->rx_queue.queue_addr[adapter->rx_queue.index].correlator;
-	ibmveth_remove_buffer_from_pool(adapter, cor, reuse);
+	rc = ibmveth_remove_buffer_from_pool(adapter, cor, reuse);
+	if (unlikely(rc))
+		return rc;
 
 	if (++adapter->rx_queue.index == adapter->rx_queue.num_slots) {
 		adapter->rx_queue.index = 0;
 		adapter->rx_queue.toggle = !adapter->rx_queue.toggle;
 	}
+
+	return 0;
 }
 
 static void ibmveth_free_tx_ltb(struct ibmveth_adapter *adapter, int idx)
@@ -709,6 +749,35 @@ static int ibmveth_close(struct net_device *netdev)
 	return 0;
 }
 
+/**
+ * ibmveth_reset - Handle scheduled reset work
+ *
+ * @w - pointer to work_struct embedded in adapter structure
+ *
+ * Context: This routine acquires rtnl_mutex and disables its NAPI through
+ *          ibmveth_close. It can't be called directly in a context that has
+ *          already acquired rtnl_mutex or disabled its NAPI, or directly from
+ *          a poll routine.
+ *
+ * Return: void
+ */
+static void ibmveth_reset(struct work_struct *w)
+{
+	struct ibmveth_adapter *adapter = container_of(w, struct ibmveth_adapter, work);
+	struct net_device *netdev = adapter->netdev;
+
+	netdev_dbg(netdev, "reset starting\n");
+
+	rtnl_lock();
+
+	dev_close(adapter->netdev);
+	dev_open(adapter->netdev, NULL);
+
+	rtnl_unlock();
+
+	netdev_dbg(netdev, "reset complete\n");
+}
+
 static int ibmveth_set_link_ksettings(struct net_device *dev,
 				      const struct ethtool_link_ksettings *cmd)
 {
@@ -1324,7 +1393,8 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
 			wmb(); /* suggested by larson1 */
 			adapter->rx_invalid_buffer++;
 			netdev_dbg(netdev, "recycling invalid buffer\n");
-			ibmveth_rxq_harvest_buffer(adapter, true);
+			if (unlikely(ibmveth_rxq_harvest_buffer(adapter, true)))
+				break;
 		} else {
 			struct sk_buff *skb, *new_skb;
 			int length = ibmveth_rxq_frame_length(adapter);
@@ -1334,6 +1404,8 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
 			__sum16 iph_check = 0;
 
 			skb = ibmveth_rxq_get_buffer(adapter);
+			if (unlikely(!skb))
+				break;
 
 			/* if the large packet bit is set in the rx queue
 			 * descriptor, the mss will be written by PHYP eight
@@ -1357,10 +1429,12 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
 				if (rx_flush)
 					ibmveth_flush_buffer(skb->data,
 						length + offset);
-				ibmveth_rxq_harvest_buffer(adapter, true);
+				if (unlikely(ibmveth_rxq_harvest_buffer(adapter, true)))
+					break;
 				skb = new_skb;
 			} else {
-				ibmveth_rxq_harvest_buffer(adapter, false);
+				if (unlikely(ibmveth_rxq_harvest_buffer(adapter, false)))
+					break;
 				skb_reserve(skb, offset);
 			}
 
@@ -1407,7 +1481,10 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
 	 * then check once more to make sure we are done.
 	 */
 	lpar_rc = h_vio_signal(adapter->vdev->unit_address, VIO_IRQ_ENABLE);
-	BUG_ON(lpar_rc != H_SUCCESS);
+	if (WARN_ON(lpar_rc != H_SUCCESS)) {
+		schedule_work(&adapter->work);
+		goto out;
+	}
 
 	if (ibmveth_rxq_pending_buffer(adapter) && napi_schedule(napi)) {
 		lpar_rc = h_vio_signal(adapter->vdev->unit_address,
@@ -1428,7 +1505,7 @@ static irqreturn_t ibmveth_interrupt(int irq, void *dev_instance)
 	if (napi_schedule_prep(&adapter->napi)) {
 		lpar_rc = h_vio_signal(adapter->vdev->unit_address,
 				       VIO_IRQ_DISABLE);
-		BUG_ON(lpar_rc != H_SUCCESS);
+		WARN_ON(lpar_rc != H_SUCCESS);
 		__napi_schedule(&adapter->napi);
 	}
 	return IRQ_HANDLED;
@@ -1670,6 +1747,7 @@ static int ibmveth_probe(struct vio_dev *dev, const struct vio_device_id *id)
 
 	adapter->vdev = dev;
 	adapter->netdev = netdev;
+	INIT_WORK(&adapter->work, ibmveth_reset);
 	adapter->mcastFilterSize = be32_to_cpu(*mcastFilterSize_p);
 	ibmveth_init_link_settings(netdev);
 
diff --git a/drivers/net/ethernet/ibm/ibmveth.h b/drivers/net/ethernet/ibm/ibmveth.h
index 8468e2c59d7a..b0a2460ec9f9 100644
--- a/drivers/net/ethernet/ibm/ibmveth.h
+++ b/drivers/net/ethernet/ibm/ibmveth.h
@@ -134,38 +134,39 @@ struct ibmveth_rx_q {
 };
 
 struct ibmveth_adapter {
-    struct vio_dev *vdev;
-    struct net_device *netdev;
-    struct napi_struct napi;
-    unsigned int mcastFilterSize;
-    void * buffer_list_addr;
-    void * filter_list_addr;
-    void *tx_ltb_ptr[IBMVETH_MAX_QUEUES];
-    unsigned int tx_ltb_size;
-    dma_addr_t tx_ltb_dma[IBMVETH_MAX_QUEUES];
-    dma_addr_t buffer_list_dma;
-    dma_addr_t filter_list_dma;
-    struct ibmveth_buff_pool rx_buff_pool[IBMVETH_NUM_BUFF_POOLS];
-    struct ibmveth_rx_q rx_queue;
-    int rx_csum;
-    int large_send;
-    bool is_active_trunk;
-
-    u64 fw_ipv6_csum_support;
-    u64 fw_ipv4_csum_support;
-    u64 fw_large_send_support;
-    /* adapter specific stats */
-    u64 replenish_task_cycles;
-    u64 replenish_no_mem;
-    u64 replenish_add_buff_failure;
-    u64 replenish_add_buff_success;
-    u64 rx_invalid_buffer;
-    u64 rx_no_buffer;
-    u64 tx_map_failed;
-    u64 tx_send_failed;
-    u64 tx_large_packets;
-    u64 rx_large_packets;
-    /* Ethtool settings */
+	struct vio_dev *vdev;
+	struct net_device *netdev;
+	struct napi_struct napi;
+	struct work_struct work;
+	unsigned int mcastFilterSize;
+	void *buffer_list_addr;
+	void *filter_list_addr;
+	void *tx_ltb_ptr[IBMVETH_MAX_QUEUES];
+	unsigned int tx_ltb_size;
+	dma_addr_t tx_ltb_dma[IBMVETH_MAX_QUEUES];
+	dma_addr_t buffer_list_dma;
+	dma_addr_t filter_list_dma;
+	struct ibmveth_buff_pool rx_buff_pool[IBMVETH_NUM_BUFF_POOLS];
+	struct ibmveth_rx_q rx_queue;
+	int rx_csum;
+	int large_send;
+	bool is_active_trunk;
+
+	u64 fw_ipv6_csum_support;
+	u64 fw_ipv4_csum_support;
+	u64 fw_large_send_support;
+	/* adapter specific stats */
+	u64 replenish_task_cycles;
+	u64 replenish_no_mem;
+	u64 replenish_add_buff_failure;
+	u64 replenish_add_buff_success;
+	u64 rx_invalid_buffer;
+	u64 rx_no_buffer;
+	u64 tx_map_failed;
+	u64 tx_send_failed;
+	u64 tx_large_packets;
+	u64 rx_large_packets;
+	/* Ethtool settings */
 	u8 duplex;
 	u32 speed;
 };
-- 
2.49.0