xen-gntdev: Fix incorrect use of zero handle
The handle with numeric value 0 is a valid map handle, so it cannot
be used to indicate that a page has not been mapped. Use -1 instead.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 2a4733c..cdc28dc 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -126,6 +126,8 @@
add->pages[i] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
if (add->pages[i] == NULL)
goto err;
+ add->map_ops[i].handle = -1;
+ add->unmap_ops[i].handle = -1;
}
add->index = 0;
@@ -248,7 +250,7 @@
map->grants[pgnr].ref,
map->grants[pgnr].domid);
gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags,
- 0 /* handle */);
+ -1 /* handle */);
return 0;
}
@@ -259,7 +261,7 @@
if (!use_ptemod) {
/* Note: it could already be mapped */
- if (map->map_ops[0].handle)
+ if (map->map_ops[0].handle != -1)
return 0;
for (i = 0; i < map->count; i++) {
addr = (phys_addr_t)
@@ -268,7 +270,7 @@
map->grants[i].ref,
map->grants[i].domid);
gnttab_set_unmap_op(&map->unmap_ops[i], addr,
- map->flags, 0 /* handle */);
+ map->flags, -1 /* handle */);
}
}
@@ -280,7 +282,11 @@
for (i = 0; i < map->count; i++) {
if (map->map_ops[i].status)
err = -EINVAL;
- map->unmap_ops[i].handle = map->map_ops[i].handle;
+ else {
+ BUG_ON(map->map_ops[i].handle == -1);
+ map->unmap_ops[i].handle = map->map_ops[i].handle;
+ pr_debug("map handle=%d\n", map->map_ops[i].handle);
+ }
}
return err;
}
@@ -313,7 +319,10 @@
for (i = 0; i < pages; i++) {
if (map->unmap_ops[offset+i].status)
err = -EINVAL;
- map->unmap_ops[offset+i].handle = 0;
+ pr_debug("unmap handle=%d st=%d\n",
+ map->unmap_ops[offset+i].handle,
+ map->unmap_ops[offset+i].status);
+ map->unmap_ops[offset+i].handle = -1;
}
return err;
}
@@ -328,13 +337,13 @@
* already unmapped some of the grants. Only unmap valid ranges.
*/
while (pages && !err) {
- while (pages && !map->unmap_ops[offset].handle) {
+ while (pages && map->unmap_ops[offset].handle == -1) {
offset++;
pages--;
}
range = 0;
while (range < pages) {
- if (!map->unmap_ops[offset+range].handle) {
+ if (map->unmap_ops[offset+range].handle == -1) {
range--;
break;
}