diff options
| -rw-r--r-- | drivers/xen/gntdev.c | 50 |
1 files changed, 14 insertions, 36 deletions
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 1e31cdcdae1e..23d208a219fa 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -45,15 +45,15 @@ MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, " "Gerd Hoffmann <kraxel@redhat.com>"); MODULE_DESCRIPTION("User-space granted page access driver"); -static int limit = 1024; +static int limit = 1024*1024; module_param(limit, int, 0644); -MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped at " - "once by a gntdev instance"); +MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped by " + "the gntdev device"); + +static atomic_t pages_mapped = ATOMIC_INIT(0); struct gntdev_priv { struct list_head maps; - uint32_t used; - uint32_t limit; /* lock protects maps from concurrent changes */ spinlock_t lock; struct mm_struct *mm; @@ -82,9 +82,7 @@ static void gntdev_print_maps(struct gntdev_priv *priv, #ifdef DEBUG struct grant_map *map; - pr_debug("maps list (priv %p, usage %d/%d)\n", - priv, priv->used, priv->limit); - + pr_debug("%s: maps list (priv %p)\n", __func__, priv); list_for_each_entry(map, &priv->maps, next) pr_debug(" index %2d, count %2d %s\n", map->index, map->count, @@ -121,9 +119,6 @@ static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count) add->count = count; add->priv = priv; - if (add->count + priv->used > priv->limit) - goto err; - return add; err: @@ -154,7 +149,6 @@ static void gntdev_add_map(struct gntdev_priv *priv, struct grant_map *add) list_add_tail(&add->next, &priv->maps); done: - priv->used += add->count; gntdev_print_maps(priv, "[new]", add->index); } @@ -200,7 +194,7 @@ static int gntdev_del_map(struct grant_map *map) if (map->unmap_ops[i].handle) return -EBUSY; - map->priv->used -= map->count; + atomic_sub(map->count, &pages_mapped); list_del(&map->next); return 0; } @@ -386,7 +380,6 @@ static int gntdev_open(struct inode *inode, struct file *flip) INIT_LIST_HEAD(&priv->maps); spin_lock_init(&priv->lock); - priv->limit = limit; priv->mm = get_task_mm(current); if (!priv->mm) { @@ -443,19 +436,24 @@ static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv, pr_debug("priv %p, add %d\n", priv, op.count); if (unlikely(op.count <= 0)) return -EINVAL; - if (unlikely(op.count > priv->limit)) - return -EINVAL; err = -ENOMEM; map = gntdev_alloc_map(priv, op.count); if (!map) return err; + if (copy_from_user(map->grants, &u->refs, sizeof(map->grants[0]) * op.count) != 0) { gntdev_free_map(map); return err; } + if (unlikely(atomic_add_return(op.count, &pages_mapped) > limit)) { + pr_debug("can't map: over limit\n"); + gntdev_free_map(map); + return err; + } + spin_lock(&priv->lock); gntdev_add_map(priv, map); op.index = map->index << PAGE_SHIFT; @@ -518,23 +516,6 @@ static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv, return 0; } -static long gntdev_ioctl_set_max_grants(struct gntdev_priv *priv, - struct ioctl_gntdev_set_max_grants __user *u) -{ - struct ioctl_gntdev_set_max_grants op; - - if (copy_from_user(&op, u, sizeof(op)) != 0) - return -EFAULT; - pr_debug("priv %p, limit %d\n", priv, op.count); - if (op.count > limit) - return -E2BIG; - - spin_lock(&priv->lock); - priv->limit = op.count; - spin_unlock(&priv->lock); - return 0; -} - static long gntdev_ioctl(struct file *flip, unsigned int cmd, unsigned long arg) { @@ -551,9 +532,6 @@ static long gntdev_ioctl(struct file *flip, case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR: return gntdev_ioctl_get_offset_for_vaddr(priv, ptr); - case IOCTL_GNTDEV_SET_MAX_GRANTS: - return gntdev_ioctl_set_max_grants(priv, ptr); - default: pr_debug("priv %p, unknown cmd %x\n", priv, cmd); return -ENOIOCTLCMD; |