1 files changed, 15 insertions, 12 deletions

diff --git a/drivers/xen/xen-scsiback.c b/drivers/xen/xen-scsiback.c
index e2f3e8b0fba9..6d5eaea3373b 100644
--- a/drivers/xen/xen-scsiback.c
+++ b/drivers/xen/xen-scsiback.c
@@ -91,7 +91,6 @@ struct vscsibk_info {
 	unsigned int irq;
 
 	struct vscsiif_back_ring ring;
-	int ring_error;
 
 	spinlock_t ring_lock;
 	atomic_t nr_unreplied_reqs;
@@ -423,12 +422,12 @@ static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
 		return 0;
 
 	err = gnttab_map_refs(map, NULL, pg, cnt);
-	BUG_ON(err);
 	for (i = 0; i < cnt; i++) {
 		if (unlikely(map[i].status != GNTST_okay)) {
 			pr_err("invalid buffer -- could not remap it\n");
 			map[i].handle = SCSIBACK_INVALID_HANDLE;
-			err = -ENOMEM;
+			if (!err)
+				err = -ENOMEM;
 		} else {
 			get_page(pg[i]);
 		}
@@ -721,7 +720,8 @@ static struct vscsibk_pend *prepare_pending_reqs(struct vscsibk_info *info,
 	return pending_req;
 }
 
-static int scsiback_do_cmd_fn(struct vscsibk_info *info)
+static int scsiback_do_cmd_fn(struct vscsibk_info *info,
+			      unsigned int *eoi_flags)
 {
 	struct vscsiif_back_ring *ring = &info->ring;
 	struct vscsiif_request ring_req;
@@ -738,11 +738,12 @@ static int scsiback_do_cmd_fn(struct vscsibk_info *info)
 		rc = ring->rsp_prod_pvt;
 		pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
 			   info->domid, rp, rc, rp - rc);
-		info->ring_error = 1;
-		return 0;
+		return -EINVAL;
 	}
 
 	while ((rc != rp)) {
+		*eoi_flags &= ~XEN_EOI_FLAG_SPURIOUS;
+
 		if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
 			break;
 
@@ -801,13 +802,16 @@ static int scsiback_do_cmd_fn(struct vscsibk_info *info)
 static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
 {
 	struct vscsibk_info *info = dev_id;
+	int rc;
+	unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
 
-	if (info->ring_error)
-		return IRQ_HANDLED;
-
-	while (scsiback_do_cmd_fn(info))
+	while ((rc = scsiback_do_cmd_fn(info, &eoi_flags)) > 0)
 		cond_resched();
 
+	/* In case of a ring error we keep the event channel masked. */
+	if (!rc)
+		xen_irq_lateeoi(irq, eoi_flags);
+
 	return IRQ_HANDLED;
 }
 
@@ -828,7 +832,7 @@ static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
 	sring = (struct vscsiif_sring *)area;
 	BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
 
-	err = bind_interdomain_evtchn_to_irq(info->domid, evtchn);
+	err = bind_interdomain_evtchn_to_irq_lateeoi(info->domid, evtchn);
 	if (err < 0)
 		goto unmap_page;
 
@@ -1251,7 +1255,6 @@ static int scsiback_probe(struct xenbus_device *dev,
 
 	info->domid = dev->otherend_id;
 	spin_lock_init(&info->ring_lock);
-	info->ring_error = 0;
 	atomic_set(&info->nr_unreplied_reqs, 0);
 	init_waitqueue_head(&info->waiting_to_free);
 	info->dev = dev;