+static struct kmem_cache *iova_cache;
+static unsigned int iova_cache_users;
+static DEFINE_MUTEX(iova_cache_mutex);
+
+struct iova *alloc_iova_mem(void)
+{
+ return kmem_cache_alloc(iova_cache, GFP_ATOMIC);
+}
+EXPORT_SYMBOL(alloc_iova_mem);
+
+void free_iova_mem(struct iova *iova)
+{
+ kmem_cache_free(iova_cache, iova);
+}
+EXPORT_SYMBOL(free_iova_mem);
+
+int iova_cache_get(void)
+{
+ mutex_lock(&iova_cache_mutex);
+ if (!iova_cache_users) {
+ iova_cache = kmem_cache_create(
+ "iommu_iova", sizeof(struct iova), 0,
+ SLAB_HWCACHE_ALIGN, NULL);
+ if (!iova_cache) {
+ mutex_unlock(&iova_cache_mutex);
+ printk(KERN_ERR "Couldn't create iova cache\n");
+ return -ENOMEM;
+ }
+ }
+
+ iova_cache_users++;
+ mutex_unlock(&iova_cache_mutex);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(iova_cache_get);
+
+void iova_cache_put(void)
+{
+ mutex_lock(&iova_cache_mutex);
+ if (WARN_ON(!iova_cache_users)) {
+ mutex_unlock(&iova_cache_mutex);
+ return;
+ }
+ iova_cache_users--;
+ if (!iova_cache_users)
+ kmem_cache_destroy(iova_cache);
+ mutex_unlock(&iova_cache_mutex);
+}
+EXPORT_SYMBOL_GPL(iova_cache_put);
+