Merge tag 'v4.0-rc2' into irq/core, to refresh the tree before applying new changes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

8 files changed, 160 insertions, 128 deletions

diff --git a/drivers/net/ethernet/cisco/enic/enic.h b/drivers/net/ethernet/cisco/enic/enic.h
index 25c4d88853d8..84b6a2b46aec 100644
--- a/drivers/net/ethernet/cisco/enic/enic.h
+++ b/drivers/net/ethernet/cisco/enic/enic.h
@@ -33,7 +33,7 @@
 
 #define DRV_NAME		"enic"
 #define DRV_DESCRIPTION		"Cisco VIC Ethernet NIC Driver"
-#define DRV_VERSION		"2.1.1.67"
+#define DRV_VERSION		"2.1.1.83"
 #define DRV_COPYRIGHT		"Copyright 2008-2013 Cisco Systems, Inc"
 
 #define ENIC_BARS_MAX		6
@@ -188,6 +188,7 @@ struct enic {
 	struct enic_rfs_flw_tbl rfs_h;
 	u32 rx_copybreak;
 	u8 rss_key[ENIC_RSS_LEN];
+	struct vnic_gen_stats gen_stats;
 };
 
 static inline struct device *enic_get_dev(struct enic *enic)
@@ -242,6 +243,19 @@ static inline unsigned int enic_msix_notify_intr(struct enic *enic)
 	return enic->rq_count + enic->wq_count + 1;
 }
 
+static inline int enic_dma_map_check(struct enic *enic, dma_addr_t dma_addr)
+{
+	if (unlikely(pci_dma_mapping_error(enic->pdev, dma_addr))) {
+		net_warn_ratelimited("%s: PCI dma mapping failed!\n",
+				     enic->netdev->name);
+		enic->gen_stats.dma_map_error++;
+
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
 void enic_reset_addr_lists(struct enic *enic);
 int enic_sriov_enabled(struct enic *enic);
 int enic_is_valid_vf(struct enic *enic, int vf);
diff --git a/drivers/net/ethernet/cisco/enic/enic_dev.c b/drivers/net/ethernet/cisco/enic/enic_dev.c
index 87ddc44b590e..f8d2a6a34282 100644
--- a/drivers/net/ethernet/cisco/enic/enic_dev.c
+++ b/drivers/net/ethernet/cisco/enic/enic_dev.c
@@ -177,40 +177,6 @@ int enic_dev_intr_coal_timer_info(struct enic *enic)
 	return err;
 }
 
-int enic_vnic_dev_deinit(struct enic *enic)
-{
-	int err;
-
-	spin_lock_bh(&enic->devcmd_lock);
-	err = vnic_dev_deinit(enic->vdev);
-	spin_unlock_bh(&enic->devcmd_lock);
-
-	return err;
-}
-
-int enic_dev_init_prov2(struct enic *enic, struct vic_provinfo *vp)
-{
-	int err;
-
-	spin_lock_bh(&enic->devcmd_lock);
-	err = vnic_dev_init_prov2(enic->vdev,
-		(u8 *)vp, vic_provinfo_size(vp));
-	spin_unlock_bh(&enic->devcmd_lock);
-
-	return err;
-}
-
-int enic_dev_deinit_done(struct enic *enic, int *status)
-{
-	int err;
-
-	spin_lock_bh(&enic->devcmd_lock);
-	err = vnic_dev_deinit_done(enic->vdev, status);
-	spin_unlock_bh(&enic->devcmd_lock);
-
-	return err;
-}
-
 /* rtnl lock is held */
 int enic_vlan_rx_add_vid(struct net_device *netdev, __be16 proto, u16 vid)
 {
@@ -237,28 +203,6 @@ int enic_vlan_rx_kill_vid(struct net_device *netdev, __be16 proto, u16 vid)
 	return err;
 }
 
-int enic_dev_enable2(struct enic *enic, int active)
-{
-	int err;
-
-	spin_lock_bh(&enic->devcmd_lock);
-	err = vnic_dev_enable2(enic->vdev, active);
-	spin_unlock_bh(&enic->devcmd_lock);
-
-	return err;
-}
-
-int enic_dev_enable2_done(struct enic *enic, int *status)
-{
-	int err;
-
-	spin_lock_bh(&enic->devcmd_lock);
-	err = vnic_dev_enable2_done(enic->vdev, status);
-	spin_unlock_bh(&enic->devcmd_lock);
-
-	return err;
-}
-
 int enic_dev_status_to_errno(int devcmd_status)
 {
 	switch (devcmd_status) {
diff --git a/drivers/net/ethernet/cisco/enic/enic_dev.h b/drivers/net/ethernet/cisco/enic/enic_dev.h
index 10bb970b2f35..f5bb058b3f96 100644
--- a/drivers/net/ethernet/cisco/enic/enic_dev.h
+++ b/drivers/net/ethernet/cisco/enic/enic_dev.h
@@ -55,11 +55,6 @@ int enic_dev_set_ig_vlan_rewrite_mode(struct enic *enic);
 int enic_dev_enable(struct enic *enic);
 int enic_dev_disable(struct enic *enic);
 int enic_dev_intr_coal_timer_info(struct enic *enic);
-int enic_vnic_dev_deinit(struct enic *enic);
-int enic_dev_init_prov2(struct enic *enic, struct vic_provinfo *vp);
-int enic_dev_deinit_done(struct enic *enic, int *status);
-int enic_dev_enable2(struct enic *enic, int arg);
-int enic_dev_enable2_done(struct enic *enic, int *status);
 int enic_dev_status_to_errno(int devcmd_status);
 
 #endif /* _ENIC_DEV_H_ */
diff --git a/drivers/net/ethernet/cisco/enic/enic_ethtool.c b/drivers/net/ethernet/cisco/enic/enic_ethtool.c
index eba1eb846d34..28d9ca675a27 100644
--- a/drivers/net/ethernet/cisco/enic/enic_ethtool.c
+++ b/drivers/net/ethernet/cisco/enic/enic_ethtool.c
@@ -24,6 +24,7 @@
 #include "enic_dev.h"
 #include "enic_clsf.h"
 #include "vnic_rss.h"
+#include "vnic_stats.h"
 
 struct enic_stat {
 	char name[ETH_GSTRING_LEN];
@@ -40,6 +41,11 @@ struct enic_stat {
 	.index = offsetof(struct vnic_rx_stats, stat) / sizeof(u64) \
 }
 
+#define ENIC_GEN_STAT(stat) { \
+	.name = #stat, \
+	.index = offsetof(struct vnic_gen_stats, stat) / sizeof(u64)\
+}
+
 static const struct enic_stat enic_tx_stats[] = {
 	ENIC_TX_STAT(tx_frames_ok),
 	ENIC_TX_STAT(tx_unicast_frames_ok),
@@ -78,10 +84,15 @@ static const struct enic_stat enic_rx_stats[] = {
 	ENIC_RX_STAT(rx_frames_to_max),
 };
 
+static const struct enic_stat enic_gen_stats[] = {
+	ENIC_GEN_STAT(dma_map_error),
+};
+
 static const unsigned int enic_n_tx_stats = ARRAY_SIZE(enic_tx_stats);
 static const unsigned int enic_n_rx_stats = ARRAY_SIZE(enic_rx_stats);
+static const unsigned int enic_n_gen_stats = ARRAY_SIZE(enic_gen_stats);
 
-void enic_intr_coal_set_rx(struct enic *enic, u32 timer)
+static void enic_intr_coal_set_rx(struct enic *enic, u32 timer)
 {
 	int i;
 	int intr;
@@ -146,6 +157,10 @@ static void enic_get_strings(struct net_device *netdev, u32 stringset,
 			memcpy(data, enic_rx_stats[i].name, ETH_GSTRING_LEN);
 			data += ETH_GSTRING_LEN;
 		}
+		for (i = 0; i < enic_n_gen_stats; i++) {
+			memcpy(data, enic_gen_stats[i].name, ETH_GSTRING_LEN);
+			data += ETH_GSTRING_LEN;
+		}
 		break;
 	}
 }
@@ -154,7 +169,7 @@ static int enic_get_sset_count(struct net_device *netdev, int sset)
 {
 	switch (sset) {
 	case ETH_SS_STATS:
-		return enic_n_tx_stats + enic_n_rx_stats;
+		return enic_n_tx_stats + enic_n_rx_stats + enic_n_gen_stats;
 	default:
 		return -EOPNOTSUPP;
 	}
@@ -173,6 +188,8 @@ static void enic_get_ethtool_stats(struct net_device *netdev,
 		*(data++) = ((u64 *)&vstats->tx)[enic_tx_stats[i].index];
 	for (i = 0; i < enic_n_rx_stats; i++)
 		*(data++) = ((u64 *)&vstats->rx)[enic_rx_stats[i].index];
+	for (i = 0; i < enic_n_gen_stats; i++)
+		*(data++) = ((u64 *)&enic->gen_stats)[enic_gen_stats[i].index];
 }
 
 static u32 enic_get_msglevel(struct net_device *netdev)
diff --git a/drivers/net/ethernet/cisco/enic/enic_main.c b/drivers/net/ethernet/cisco/enic/enic_main.c
index b29e027c476e..9cbe038a388e 100644
--- a/drivers/net/ethernet/cisco/enic/enic_main.c
+++ b/drivers/net/ethernet/cisco/enic/enic_main.c
@@ -45,6 +45,7 @@
 #ifdef CONFIG_NET_RX_BUSY_POLL
 #include <net/busy_poll.h>
 #endif
+#include <linux/crash_dump.h>
 
 #include "cq_enet_desc.h"
 #include "vnic_dev.h"
@@ -88,7 +89,7 @@ MODULE_DEVICE_TABLE(pci, enic_id_table);
  *  coalescing timer values
  *  {rx_rate in Mbps, mapping percentage of the range}
  */
-struct enic_intr_mod_table mod_table[ENIC_MAX_COALESCE_TIMERS + 1] = {
+static struct enic_intr_mod_table mod_table[ENIC_MAX_COALESCE_TIMERS + 1] = {
 	{4000,  0},
 	{4400, 10},
 	{5060, 20},
@@ -105,7 +106,7 @@ struct enic_intr_mod_table mod_table[ENIC_MAX_COALESCE_TIMERS + 1] = {
 /* This table helps the driver to pick different ranges for rx coalescing
  * timer depending on the link speed.
  */
-struct enic_intr_mod_range mod_range[ENIC_MAX_LINK_SPEEDS] = {
+static struct enic_intr_mod_range mod_range[ENIC_MAX_LINK_SPEEDS] = {
 	{0,  0}, /* 0  - 4  Gbps */
 	{0,  3}, /* 4  - 10 Gbps */
 	{3,  6}, /* 10 - 40 Gbps */
@@ -351,80 +352,94 @@ static irqreturn_t enic_isr_msix_notify(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
-static inline void enic_queue_wq_skb_cont(struct enic *enic,
-	struct vnic_wq *wq, struct sk_buff *skb,
-	unsigned int len_left, int loopback)
+static int enic_queue_wq_skb_cont(struct enic *enic, struct vnic_wq *wq,
+				  struct sk_buff *skb, unsigned int len_left,
+				  int loopback)
 {
 	const skb_frag_t *frag;
+	dma_addr_t dma_addr;
 
 	/* Queue additional data fragments */
 	for (frag = skb_shinfo(skb)->frags; len_left; frag++) {
 		len_left -= skb_frag_size(frag);
-		enic_queue_wq_desc_cont(wq, skb,
-			skb_frag_dma_map(&enic->pdev->dev,
-					 frag, 0, skb_frag_size(frag),
-					 DMA_TO_DEVICE),
-			skb_frag_size(frag),
-			(len_left == 0),	/* EOP? */
-			loopback);
+		dma_addr = skb_frag_dma_map(&enic->pdev->dev, frag, 0,
+					    skb_frag_size(frag),
+					    DMA_TO_DEVICE);
+		if (unlikely(enic_dma_map_check(enic, dma_addr)))
+			return -ENOMEM;
+		enic_queue_wq_desc_cont(wq, skb, dma_addr, skb_frag_size(frag),
+					(len_left == 0),	/* EOP? */
+					loopback);
 	}
+
+	return 0;
 }
 
-static inline void enic_queue_wq_skb_vlan(struct enic *enic,
-	struct vnic_wq *wq, struct sk_buff *skb,
-	int vlan_tag_insert, unsigned int vlan_tag, int loopback)
+static int enic_queue_wq_skb_vlan(struct enic *enic, struct vnic_wq *wq,
+				  struct sk_buff *skb, int vlan_tag_insert,
+				  unsigned int vlan_tag, int loopback)
 {
 	unsigned int head_len = skb_headlen(skb);
 	unsigned int len_left = skb->len - head_len;
 	int eop = (len_left == 0);
+	dma_addr_t dma_addr;
+	int err = 0;
+
+	dma_addr = pci_map_single(enic->pdev, skb->data, head_len,
+				  PCI_DMA_TODEVICE);
+	if (unlikely(enic_dma_map_check(enic, dma_addr)))
+		return -ENOMEM;
 
 	/* Queue the main skb fragment. The fragments are no larger
 	 * than max MTU(9000)+ETH_HDR_LEN(14) bytes, which is less
 	 * than WQ_ENET_MAX_DESC_LEN length. So only one descriptor
 	 * per fragment is queued.
 	 */
-	enic_queue_wq_desc(wq, skb,
-		pci_map_single(enic->pdev, skb->data,
-			head_len, PCI_DMA_TODEVICE),
-		head_len,
-		vlan_tag_insert, vlan_tag,
-		eop, loopback);
+	enic_queue_wq_desc(wq, skb, dma_addr, head_len,	vlan_tag_insert,
+			   vlan_tag, eop, loopback);
 
 	if (!eop)
-		enic_queue_wq_skb_cont(enic, wq, skb, len_left, loopback);
+		err = enic_queue_wq_skb_cont(enic, wq, skb, len_left, loopback);
+
+	return err;
 }
 
-static inline void enic_queue_wq_skb_csum_l4(struct enic *enic,
-	struct vnic_wq *wq, struct sk_buff *skb,
-	int vlan_tag_insert, unsigned int vlan_tag, int loopback)
+static int enic_queue_wq_skb_csum_l4(struct enic *enic, struct vnic_wq *wq,
+				     struct sk_buff *skb, int vlan_tag_insert,
+				     unsigned int vlan_tag, int loopback)
 {
 	unsigned int head_len = skb_headlen(skb);
 	unsigned int len_left = skb->len - head_len;
 	unsigned int hdr_len = skb_checksum_start_offset(skb);
 	unsigned int csum_offset = hdr_len + skb->csum_offset;
 	int eop = (len_left == 0);
+	dma_addr_t dma_addr;
+	int err = 0;
+
+	dma_addr = pci_map_single(enic->pdev, skb->data, head_len,
+				  PCI_DMA_TODEVICE);
+	if (unlikely(enic_dma_map_check(enic, dma_addr)))
+		return -ENOMEM;
 
 	/* Queue the main skb fragment. The fragments are no larger
 	 * than max MTU(9000)+ETH_HDR_LEN(14) bytes, which is less
 	 * than WQ_ENET_MAX_DESC_LEN length. So only one descriptor
 	 * per fragment is queued.
 	 */
-	enic_queue_wq_desc_csum_l4(wq, skb,
-		pci_map_single(enic->pdev, skb->data,
-			head_len, PCI_DMA_TODEVICE),
-		head_len,
-		csum_offset,
-		hdr_len,
-		vlan_tag_insert, vlan_tag,
-		eop, loopback);
+	enic_queue_wq_desc_csum_l4(wq, skb, dma_addr, head_len,	csum_offset,
+				   hdr_len, vlan_tag_insert, vlan_tag, eop,
+				   loopback);
 
 	if (!eop)
-		enic_queue_wq_skb_cont(enic, wq, skb, len_left, loopback);
+		err = enic_queue_wq_skb_cont(enic, wq, skb, len_left, loopback);
+
+	return err;
 }
 
-static inline void enic_queue_wq_skb_tso(struct enic *enic,
-	struct vnic_wq *wq, struct sk_buff *skb, unsigned int mss,
-	int vlan_tag_insert, unsigned int vlan_tag, int loopback)
+static int enic_queue_wq_skb_tso(struct enic *enic, struct vnic_wq *wq,
+				 struct sk_buff *skb, unsigned int mss,
+				 int vlan_tag_insert, unsigned int vlan_tag,
+				 int loopback)
 {
 	unsigned int frag_len_left = skb_headlen(skb);
 	unsigned int len_left = skb->len - frag_len_left;
@@ -454,20 +469,19 @@ static inline void enic_queue_wq_skb_tso(struct enic *enic,
 	 */
 	while (frag_len_left) {
 		len = min(frag_len_left, (unsigned int)WQ_ENET_MAX_DESC_LEN);
-		dma_addr = pci_map_single(enic->pdev, skb->data + offset,
-				len, PCI_DMA_TODEVICE);
-		enic_queue_wq_desc_tso(wq, skb,
-			dma_addr,
-			len,
-			mss, hdr_len,
-			vlan_tag_insert, vlan_tag,
-			eop && (len == frag_len_left), loopback);
+		dma_addr = pci_map_single(enic->pdev, skb->data + offset, len,
+					  PCI_DMA_TODEVICE);
+		if (unlikely(enic_dma_map_check(enic, dma_addr)))
+			return -ENOMEM;
+		enic_queue_wq_desc_tso(wq, skb, dma_addr, len, mss, hdr_len,
+				       vlan_tag_insert, vlan_tag,
+				       eop && (len == frag_len_left), loopback);
 		frag_len_left -= len;
 		offset += len;
 	}
 
 	if (eop)
-		return;
+		return 0;
 
 	/* Queue WQ_ENET_MAX_DESC_LEN length descriptors
 	 * for additional data fragments
@@ -483,16 +497,18 @@ static inline void enic_queue_wq_skb_tso(struct enic *enic,
 			dma_addr = skb_frag_dma_map(&enic->pdev->dev, frag,
 						    offset, len,
 						    DMA_TO_DEVICE);
-			enic_queue_wq_desc_cont(wq, skb,
-				dma_addr,
-				len,
-				(len_left == 0) &&
-				(len == frag_len_left),		/* EOP? */
-				loopback);
+			if (unlikely(enic_dma_map_check(enic, dma_addr)))
+				return -ENOMEM;
+			enic_queue_wq_desc_cont(wq, skb, dma_addr, len,
+						(len_left == 0) &&
+						 (len == frag_len_left),/*EOP*/
+						loopback);
 			frag_len_left -= len;
 			offset += len;
 		}
 	}
+
+	return 0;
 }
 
 static inline void enic_queue_wq_skb(struct enic *enic,
@@ -502,25 +518,42 @@ static inline void enic_queue_wq_skb(struct enic *enic,
 	unsigned int vlan_tag = 0;
 	int vlan_tag_insert = 0;
 	int loopback = 0;
+	int err;
 
-	if (vlan_tx_tag_present(skb)) {
+	if (skb_vlan_tag_present(skb)) {
 		/* VLAN tag from trunking driver */
 		vlan_tag_insert = 1;
-		vlan_tag = vlan_tx_tag_get(skb);
+		vlan_tag = skb_vlan_tag_get(skb);
 	} else if (enic->loop_enable) {
 		vlan_tag = enic->loop_tag;
 		loopback = 1;
 	}
 
 	if (mss)
-		enic_queue_wq_skb_tso(enic, wq, skb, mss,
-			vlan_tag_insert, vlan_tag, loopback);
+		err = enic_queue_wq_skb_tso(enic, wq, skb, mss,
+					    vlan_tag_insert, vlan_tag,
+					    loopback);
 	else if	(skb->ip_summed == CHECKSUM_PARTIAL)
-		enic_queue_wq_skb_csum_l4(enic, wq, skb,
-			vlan_tag_insert, vlan_tag, loopback);
+		err = enic_queue_wq_skb_csum_l4(enic, wq, skb, vlan_tag_insert,
+						vlan_tag, loopback);
 	else
-		enic_queue_wq_skb_vlan(enic, wq, skb,
-			vlan_tag_insert, vlan_tag, loopback);
+		err = enic_queue_wq_skb_vlan(enic, wq, skb, vlan_tag_insert,
+					     vlan_tag, loopback);
+	if (unlikely(err)) {
+		struct vnic_wq_buf *buf;
+
+		buf = wq->to_use->prev;
+		/* while not EOP of previous pkt && queue not empty.
+		 * For all non EOP bufs, os_buf is NULL.
+		 */
+		while (!buf->os_buf && (buf->next != wq->to_clean)) {
+			enic_free_wq_buf(wq, buf);
+			wq->ring.desc_avail++;
+			buf = buf->prev;
+		}
+		wq->to_use = buf->next;
+		dev_kfree_skb(skb);
+	}
 }
 
 /* netif_tx_lock held, process context with BHs disabled, or BH */
@@ -950,8 +983,12 @@ static int enic_rq_alloc_buf(struct vnic_rq *rq)
 	if (!skb)
 		return -ENOMEM;
 
-	dma_addr = pci_map_single(enic->pdev, skb->data,
-		len, PCI_DMA_FROMDEVICE);
+	dma_addr = pci_map_single(enic->pdev, skb->data, len,
+				  PCI_DMA_FROMDEVICE);
+	if (unlikely(enic_dma_map_check(enic, dma_addr))) {
+		dev_kfree_skb(skb);
+		return -ENOMEM;
+	}
 
 	enic_queue_rq_desc(rq, skb, os_buf_index,
 		dma_addr, len);
@@ -1266,7 +1303,7 @@ static void enic_set_rx_cpu_rmap(struct enic *enic)
 #endif /* CONFIG_RFS_ACCEL */
 
 #ifdef CONFIG_NET_RX_BUSY_POLL
-int enic_busy_poll(struct napi_struct *napi)
+static int enic_busy_poll(struct napi_struct *napi)
 {
 	struct net_device *netdev = napi->dev;
 	struct enic *enic = netdev_priv(netdev);
@@ -1335,7 +1372,7 @@ static int enic_poll_msix_rq(struct napi_struct *napi, int budget)
 	int err;
 
 	if (!enic_poll_lock_napi(&enic->rq[rq]))
-		return work_done;
+		return budget;
 	/* Service RQ
 	 */
 
@@ -2231,6 +2268,18 @@ static void enic_dev_deinit(struct enic *enic)
 	enic_clear_intr_mode(enic);
 }
 
+static void enic_kdump_kernel_config(struct enic *enic)
+{
+	if (is_kdump_kernel()) {
+		dev_info(enic_get_dev(enic), "Running from within kdump kernel. Using minimal resources\n");
+		enic->rq_count = 1;
+		enic->wq_count = 1;
+		enic->config.rq_desc_count = ENIC_MIN_RQ_DESCS;
+		enic->config.wq_desc_count = ENIC_MIN_WQ_DESCS;
+		enic->config.mtu = min_t(u16, 1500, enic->config.mtu);
+	}
+}
+
 static int enic_dev_init(struct enic *enic)
 {
 	struct device *dev = enic_get_dev(enic);
@@ -2260,6 +2309,10 @@ static int enic_dev_init(struct enic *enic)
 
 	enic_get_res_counts(enic);
 
+	/* modify resource count if we are in kdump_kernel
+	 */
+	enic_kdump_kernel_config(enic);
+
 	/* Set interrupt mode based on resource counts and system
 	 * capabilities
 	 */
diff --git a/drivers/net/ethernet/cisco/enic/vnic_stats.h b/drivers/net/ethernet/cisco/enic/vnic_stats.h
index 77750ec93954..74c81ed6fdab 100644
--- a/drivers/net/ethernet/cisco/enic/vnic_stats.h
+++ b/drivers/net/ethernet/cisco/enic/vnic_stats.h
@@ -62,6 +62,11 @@ struct vnic_rx_stats {
 	u64 rsvd[16];
 };
 
+/* Generic statistics */
+struct vnic_gen_stats {
+	u64 dma_map_error;
+};
+
 struct vnic_stats {
 	struct vnic_tx_stats tx;
 	struct vnic_rx_stats rx;
diff --git a/drivers/net/ethernet/cisco/enic/vnic_wq.c b/drivers/net/ethernet/cisco/enic/vnic_wq.c
index 3e6b8d54dafc..b5a1c937fad2 100644
--- a/drivers/net/ethernet/cisco/enic/vnic_wq.c
+++ b/drivers/net/ethernet/cisco/enic/vnic_wq.c
@@ -47,11 +47,14 @@ static int vnic_wq_alloc_bufs(struct vnic_wq *wq)
 				wq->ring.desc_size * buf->index;
 			if (buf->index + 1 == count) {
 				buf->next = wq->bufs[0];
+				buf->next->prev = buf;
 				break;
 			} else if (j + 1 == VNIC_WQ_BUF_BLK_ENTRIES(count)) {
 				buf->next = wq->bufs[i + 1];
+				buf->next->prev = buf;
 			} else {
 				buf->next = buf + 1;
+				buf->next->prev = buf;
 				buf++;
 			}
 		}
diff --git a/drivers/net/ethernet/cisco/enic/vnic_wq.h b/drivers/net/ethernet/cisco/enic/vnic_wq.h
index 816f1ad6072f..296154351823 100644
--- a/drivers/net/ethernet/cisco/enic/vnic_wq.h
+++ b/drivers/net/ethernet/cisco/enic/vnic_wq.h
@@ -62,6 +62,7 @@ struct vnic_wq_buf {
 	uint8_t cq_entry; /* Gets completion event from hw */
 	uint8_t desc_skip_cnt; /* Num descs to occupy */
 	uint8_t compressed_send; /* Both hdr and payload in one desc */
+	struct vnic_wq_buf *prev;
 };
 
 /* Break the vnic_wq_buf allocations into blocks of 32/64 entries */