From 77c35acb7c81cd94c6b30a3bef488dd2d8145131 Mon Sep 17 00:00:00 2001 From: Daniel De Graaf Date: Wed, 23 Feb 2011 08:11:35 -0500 Subject: [PATCH] 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 Signed-off-by: Konrad Rzeszutek Wilk --- drivers/xen/gntdev.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 2a4733c621c0..cdc28dc8b5d9 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -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; } -- 2.39.2