[PATCH 1/3] Xen/gntdev: don't needlessly allocate k{,un}map_ops[]

[Jan Beulich <jbeulich@xxxxxxxx>]

They're needed only in the not-auto-translate (i.e. PV) case; there's no
point in allocating memory that's never going to get accessed.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -136,17 +136,20 @@ struct gntdev_grant_map *gntdev_alloc_ma
        add->grants    = kvcalloc(count, sizeof(add->grants[0]), GFP_KERNEL);
        add->map_ops   = kvcalloc(count, sizeof(add->map_ops[0]), GFP_KERNEL);
        add->unmap_ops = kvcalloc(count, sizeof(add->unmap_ops[0]), GFP_KERNEL);
-       add->kmap_ops  = kvcalloc(count, sizeof(add->kmap_ops[0]), GFP_KERNEL);
-       add->kunmap_ops = kvcalloc(count,
-                                  sizeof(add->kunmap_ops[0]), GFP_KERNEL);
        add->pages     = kvcalloc(count, sizeof(add->pages[0]), GFP_KERNEL);
        if (NULL == add->grants    ||
            NULL == add->map_ops   ||
            NULL == add->unmap_ops ||
-           NULL == add->kmap_ops  ||
-           NULL == add->kunmap_ops ||
            NULL == add->pages)
                goto err;
+       if (use_ptemod) {
+               add->kmap_ops   = kvcalloc(count, sizeof(add->kmap_ops[0]),
+                                          GFP_KERNEL);
+               add->kunmap_ops = kvcalloc(count, sizeof(add->kunmap_ops[0]),
+                                          GFP_KERNEL);
+               if (NULL == add->kmap_ops || NULL == add->kunmap_ops)
+                       goto err;
+       }
 
 #ifdef CONFIG_XEN_GRANT_DMA_ALLOC
        add->dma_flags = dma_flags;
@@ -185,8 +188,10 @@ struct gntdev_grant_map *gntdev_alloc_ma
        for (i = 0; i < count; i++) {
                add->map_ops[i].handle = -1;
                add->unmap_ops[i].handle = -1;
-               add->kmap_ops[i].handle = -1;
-               add->kunmap_ops[i].handle = -1;
+               if (use_ptemod) {
+                       add->kmap_ops[i].handle = -1;
+                       add->kunmap_ops[i].handle = -1;
+               }
        }
 
        add->index = 0;
@@ -332,8 +337,8 @@ int gntdev_map_grant_pages(struct gntdev
        }
 
        pr_debug("map %d+%d\n", map->index, map->count);
-       err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL,
-                       map->pages, map->count);
+       err = gnttab_map_refs(map->map_ops, map->kmap_ops, map->pages,
+                       map->count);
 
        for (i = 0; i < map->count; i++) {
                if (map->map_ops[i].status == GNTST_okay)