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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>
This commit is contained in:
Daniel De Graaf 2011-02-23 08:11:35 -05:00 committed by Konrad Rzeszutek Wilk
parent 1f169f66dd
commit 77c35acb7c
1 changed files with 16 additions and 7 deletions
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23
drivers/xen/gntdev.c
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@ -126,6 +126,8 @@ static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count)
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 @@ static int find_grant_ptes(pte_t *pte, pgtable_t token,
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 @@ static int map_grant_pages(struct grant_map *map)
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 @@ static int map_grant_pages(struct grant_map *map)
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 @@ static int map_grant_pages(struct grant_map *map)
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 @@ static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
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 @@ static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
* 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;
}