--- zzzz-none-000/linux-3.10.107/drivers/xen/gntalloc.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/xen/gntalloc.c	2021-02-04 17:41:59.000000000 +0000
@@ -48,6 +48,8 @@
  * grant operation.
  */
 
+#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
+
 #include <linux/atomic.h>
 #include <linux/module.h>
 #include <linux/miscdevice.h>
@@ -122,7 +124,7 @@
 	int i, rc, readonly;
 	LIST_HEAD(queue_gref);
 	LIST_HEAD(queue_file);
-	struct gntalloc_gref *gref;
+	struct gntalloc_gref *gref, *next;
 
 	readonly = !(op->flags & GNTALLOC_FLAG_WRITABLE);
 	rc = -ENOMEM;
@@ -139,13 +141,12 @@
 			goto undo;
 
 		/* Grant foreign access to the page. */
-		gref->gref_id = gnttab_grant_foreign_access(op->domid,
-			pfn_to_mfn(page_to_pfn(gref->page)), readonly);
-		if ((int)gref->gref_id < 0) {
-			rc = gref->gref_id;
+		rc = gnttab_grant_foreign_access(op->domid,
+						 xen_page_to_gfn(gref->page),
+						 readonly);
+		if (rc < 0)
 			goto undo;
-		}
-		gref_ids[i] = gref->gref_id;
+		gref_ids[i] = gref->gref_id = rc;
 	}
 
 	/* Add to gref lists. */
@@ -160,8 +161,8 @@
 	mutex_lock(&gref_mutex);
 	gref_size -= (op->count - i);
 
-	list_for_each_entry(gref, &queue_file, next_file) {
-		/* __del_gref does not remove from queue_file */
+	list_for_each_entry_safe(gref, next, &queue_file, next_file) {
+		list_del(&gref->next_file);
 		__del_gref(gref);
 	}
 
@@ -191,7 +192,7 @@
 
 	gref->notify.flags = 0;
 
-	if (gref->gref_id > 0) {
+	if (gref->gref_id) {
 		if (gnttab_query_foreign_access(gref->gref_id))
 			return;
 
@@ -493,7 +494,7 @@
 	mutex_unlock(&gref_mutex);
 }
 
-static struct vm_operations_struct gntalloc_vmops = {
+static const struct vm_operations_struct gntalloc_vmops = {
 	.open = gntalloc_vma_open,
 	.close = gntalloc_vma_close,
 };
@@ -507,7 +508,7 @@
 	int rv, i;
 
 	if (!(vma->vm_flags & VM_SHARED)) {
-		printk(KERN_ERR "%s: Mapping must be shared.\n", __func__);
+		pr_err("%s: Mapping must be shared\n", __func__);
 		return -EINVAL;
 	}
 
@@ -584,7 +585,7 @@
 
 	err = misc_register(&gntalloc_miscdev);
 	if (err != 0) {
-		printk(KERN_ERR "Could not register misc gntalloc device\n");
+		pr_err("Could not register misc gntalloc device\n");
 		return err;
 	}