enic: Bug Fix: Handle surprise hardware removals

Handle surprise hardware removals gracefully during devcmd issue and init,
cleanup of queues.

Signed-off-by: Scott Feldman <scofeldm@cisco.com>
Signed-off-by: Vasanthy Kolluri <vkolluri@cisco.com>
Signed-off-by: Roopa Prabhu <roprabhu@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/enic/vnic_dev.c

@@ -275,6 +275,11 @@ static int _vnic_dev_cmd(struct vnic_dev *vdev, enum vnic_devcmd_cmd cmd,
 	int err;
 
 	status = ioread32(&devcmd->status);
+	if (status == 0xFFFFFFFF) {
+		/* PCI-e target device is gone */
+		return -ENODEV;
+	}
+
 	if (status & STAT_BUSY) {
 		pr_err("Busy devcmd %d\n", _CMD_N(cmd));
 		return -EBUSY;
@@ -296,6 +301,10 @@ static int _vnic_dev_cmd(struct vnic_dev *vdev, enum vnic_devcmd_cmd cmd,
 		udelay(100);
 
 		status = ioread32(&devcmd->status);
+		if (status == 0xFFFFFFFF) {
+			/* PCI-e target device is gone */
+			return -ENODEV;
+		}
 
 		if (!(status & STAT_BUSY)) {
 

drivers/net/enic/vnic_rq.c

@@ -146,6 +146,11 @@ void vnic_rq_init(struct vnic_rq *rq, unsigned int cq_index,
 	/* Use current fetch_index as the ring starting point */
 	fetch_index = ioread32(&rq->ctrl->fetch_index);
 
+	if (fetch_index == 0xFFFFFFFF) { /* check for hardware gone  */
+		/* Hardware surprise removal: reset fetch_index */
+		fetch_index = 0;
+	}
+
 	vnic_rq_init_start(rq, cq_index,
 		fetch_index, fetch_index,
 		error_interrupt_enable,
@@ -187,8 +192,6 @@ void vnic_rq_clean(struct vnic_rq *rq,
 	u32 fetch_index;
 	unsigned int count = rq->ring.desc_count;
 
-	BUG_ON(ioread32(&rq->ctrl->enable));
-
 	buf = rq->to_clean;
 
 	while (vnic_rq_desc_used(rq) > 0) {
@@ -201,6 +204,12 @@ void vnic_rq_clean(struct vnic_rq *rq,
 
 	/* Use current fetch_index as the ring starting point */
 	fetch_index = ioread32(&rq->ctrl->fetch_index);
+
+	if (fetch_index == 0xFFFFFFFF) { /* check for hardware gone  */
+		/* Hardware surprise removal: reset fetch_index */
+		fetch_index = 0;
+	}
+
 	rq->to_use = rq->to_clean =
 		&rq->bufs[fetch_index / VNIC_RQ_BUF_BLK_ENTRIES(count)]
 			[fetch_index % VNIC_RQ_BUF_BLK_ENTRIES(count)];

drivers/net/enic/vnic_wq.c

@@ -178,8 +178,6 @@ void vnic_wq_clean(struct vnic_wq *wq,
 {
 	struct vnic_wq_buf *buf;
 
-	BUG_ON(ioread32(&wq->ctrl->enable));
-
 	buf = wq->to_clean;
 
 	while (vnic_wq_desc_used(wq) > 0) {