drm: update user token hashing and map handles

Keep hashed user tokens, with the following changes:
32-bit physical device addresses are mapped directly to user-tokens. No
    duplicate maps are allowed, and the addresses are assumed to be outside
    of the range 0x10000000 through 0x30000000. The user-token is identical
    to the 32-bit physical start-address of the map.
64-bit physical device addressed are mapped to user-tokens in the range
0x10000000 to 0x30000000 with page-size increments. The user_token should
    not be interpreted as an address.
Other map types, like upcoming TTM maps are mapped to user-tokens in the
    range
0x10000000 to 0x30000000 with page-size increments. The user_token should
    not be interpreted as an address.

Implement hashed map lookups.
Signed-off-by: Dave Airlie <airlied@linux.ie>

drivers/char/drm/drmP.h

@@ -140,6 +140,7 @@
 #define DRM_MEM_HASHTAB   23
 
 #define DRM_MAX_CTXBITMAP (PAGE_SIZE * 8)
+#define DRM_MAP_HASH_OFFSET 0x10000000
 
 /*@}*/
 
@@ -485,6 +486,7 @@ typedef struct drm_sigdata {
  */
 typedef struct drm_map_list {
 	struct list_head head;		/**< list head */
+	drm_hash_item_t hash;
 	drm_map_t *map;			/**< mapping */
 	unsigned int user_token;
 } drm_map_list_t;
@@ -662,6 +664,7 @@ typedef struct drm_device {
 	/*@{ */
 	drm_map_list_t *maplist;	/**< Linked list of regions */
 	int map_count;			/**< Number of mappable regions */
+	drm_open_hash_t map_hash;	/**< User token hash table for maps */
 
 	/** \name Context handle management */
 	/*@{ */

drivers/char/drm/drm_bufs.c

@@ -65,43 +65,27 @@ static drm_map_list_t *drm_find_matching_map(drm_device_t *dev,
 	return NULL;
 }
 
-/*
- * Used to allocate 32-bit handles for mappings.
- */
-#define START_RANGE 0x10000000
-#define END_RANGE 0x40000000
-
-#ifdef _LP64
-static __inline__ unsigned int HandleID(unsigned long lhandle,
-					drm_device_t *dev)
+int drm_map_handle(drm_device_t *dev, drm_hash_item_t *hash,
+		   unsigned long user_token, int hashed_handle)
 {
-	static unsigned int map32_handle = START_RANGE;
-	unsigned int hash;
-
-	if (lhandle & 0xffffffff00000000) {
-		hash = map32_handle;
-		map32_handle += PAGE_SIZE;
-		if (map32_handle > END_RANGE)
-			map32_handle = START_RANGE;
-	} else
-		hash = lhandle;
-
-	while (1) {
-		drm_map_list_t *_entry;
-		list_for_each_entry(_entry, &dev->maplist->head, head) {
-			if (_entry->user_token == hash)
-				break;
-		}
-		if (&_entry->head == &dev->maplist->head)
-			return hash;
+	int use_hashed_handle;
+	#if (BITS_PER_LONG == 64)
+	use_hashed_handle = ((user_token & 0xFFFFFFFF00000000UL) || hashed_handle);
+#elif (BITS_PER_LONG == 32)
+	use_hashed_handle = hashed_handle;
+#else
+#error Unsupported long size. Neither 64 nor 32 bits.
+#endif
 
-		hash += PAGE_SIZE;
-		map32_handle += PAGE_SIZE;
+	if (use_hashed_handle) {
+		return drm_ht_just_insert_please(&dev->map_hash, hash,
+						 user_token, 32 - PAGE_SHIFT - 3,
+						 PAGE_SHIFT, DRM_MAP_HASH_OFFSET);
+	} else {
+		hash->key = user_token;
+		return drm_ht_insert_item(&dev->map_hash, hash);
 	}
 }
-#else
-# define HandleID(x,dev) (unsigned int)(x)
-#endif
 
 /**
  * Ioctl to specify a range of memory that is available for mapping by a non-root process.
@@ -123,6 +107,8 @@ static int drm_addmap_core(drm_device_t * dev, unsigned int offset,
 	drm_map_t *map;
 	drm_map_list_t *list;
 	drm_dma_handle_t *dmah;
+	unsigned long user_token;
+	int ret;
 
 	map = drm_alloc(sizeof(*map), DRM_MEM_MAPS);
 	if (!map)
@@ -257,11 +243,20 @@ static int drm_addmap_core(drm_device_t * dev, unsigned int offset,
 
 	mutex_lock(&dev->struct_mutex);
 	list_add(&list->head, &dev->maplist->head);
+
 	/* Assign a 32-bit handle */
 	/* We do it here so that dev->struct_mutex protects the increment */
-	list->user_token = HandleID(map->type == _DRM_SHM
-				    ? (unsigned long)map->handle
-				    : map->offset, dev);
+	user_token = (map->type == _DRM_SHM) ? (unsigned long)map->handle :
+		map->offset;
+	ret = drm_map_handle(dev, &list->hash, user_token, FALSE);
+	if (ret) {
+		drm_free(map, sizeof(*map), DRM_MEM_MAPS);
+		drm_free(list, sizeof(*list), DRM_MEM_MAPS);
+		mutex_unlock(&dev->struct_mutex);
+		return ret;
+	}
+
+	list->user_token = list->hash.key;
 	mutex_unlock(&dev->struct_mutex);
 
 	*maplist = list;
@@ -346,6 +341,7 @@ int drm_rmmap_locked(drm_device_t *dev, drm_local_map_t *map)
 
 		if (r_list->map == map) {
 			list_del(list);
+			drm_ht_remove_key(&dev->map_hash, r_list->user_token);
 			drm_free(list, sizeof(*list), DRM_MEM_MAPS);
 			break;
 		}

drivers/char/drm/drm_hashtab.h

@@ -35,7 +35,7 @@
 #ifndef DRM_HASHTAB_H
 #define DRM_HASHTAB_H
 
-#define drm_hash_entry(_ptr, _type, _member) list_entry(_ptr, _type, _member)
+#define drm_hash_entry(_ptr, _type, _member) container_of(_ptr, _type, _member)
 
 typedef struct drm_hash_item{
 	struct hlist_node head;

drivers/char/drm/drm_stub.c

@@ -75,6 +75,10 @@ static int drm_fill_in_dev(drm_device_t * dev, struct pci_dev *pdev,
 	if (dev->maplist == NULL)
 		return -ENOMEM;
 	INIT_LIST_HEAD(&dev->maplist->head);
+	if (drm_ht_create(&dev->map_hash, 12)) {
+		drm_free(dev->maplist, sizeof(*dev->maplist), DRM_MEM_MAPS);
+		return -ENOMEM;
+	}
 
 	/* the DRM has 6 basic counters */
 	dev->counters = 6;

drivers/char/drm/drm_vm.c

@@ -59,7 +59,7 @@ static __inline__ struct page *drm_do_vm_nopage(struct vm_area_struct *vma,
 	drm_device_t *dev = priv->head->dev;
 	drm_map_t *map = NULL;
 	drm_map_list_t *r_list;
-	struct list_head *list;
+	drm_hash_item_t *hash;
 
 	/*
 	 * Find the right map
@@ -70,14 +70,11 @@ static __inline__ struct page *drm_do_vm_nopage(struct vm_area_struct *vma,
 	if (!dev->agp || !dev->agp->cant_use_aperture)
 		goto vm_nopage_error;
 
-	list_for_each(list, &dev->maplist->head) {
-		r_list = list_entry(list, drm_map_list_t, head);
+	if (drm_ht_find_item(&dev->map_hash, vma->vm_pgoff << PAGE_SHIFT, &hash))
+		goto vm_nopage_error;
+
+	r_list = drm_hash_entry(hash, drm_map_list_t, hash);
 	map = r_list->map;
-		if (!map)
-			continue;
-		if (r_list->user_token == (vma->vm_pgoff << PAGE_SHIFT))
-			break;
-	}
 
 	if (map && map->type == _DRM_AGP) {
 		unsigned long offset = address - vma->vm_start;
@@ -521,9 +518,8 @@ int drm_mmap(struct file *filp, struct vm_area_struct *vma)
 	drm_file_t *priv = filp->private_data;
 	drm_device_t *dev = priv->head->dev;
 	drm_map_t *map = NULL;
-	drm_map_list_t *r_list;
 	unsigned long offset = 0;
-	struct list_head *list;
+	drm_hash_item_t *hash;
 
 	DRM_DEBUG("start = 0x%lx, end = 0x%lx, offset = 0x%lx\n",
 		  vma->vm_start, vma->vm_end, vma->vm_pgoff << PAGE_SHIFT);
@@ -543,23 +539,12 @@ int drm_mmap(struct file *filp, struct vm_area_struct *vma)
 	    )
 		return drm_mmap_dma(filp, vma);
 
-	/* A sequential search of a linked list is
-	   fine here because: 1) there will only be
-	   about 5-10 entries in the list and, 2) a
-	   DRI client only has to do this mapping
-	   once, so it doesn't have to be optimized
-	   for performance, even if the list was a
-	   bit longer. */
-	list_for_each(list, &dev->maplist->head) {
-
-		r_list = list_entry(list, drm_map_list_t, head);
-		map = r_list->map;
-		if (!map)
-			continue;
-		if (r_list->user_token == vma->vm_pgoff << PAGE_SHIFT)
-			break;
+	if (drm_ht_find_item(&dev->map_hash, vma->vm_pgoff << PAGE_SHIFT, &hash)) {
+		DRM_ERROR("Could not find map\n");
+		return -EINVAL;
 	}
 
+	map = drm_hash_entry(hash, drm_map_list_t, hash)->map;
 	if (!map || ((map->flags & _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN)))
 		return -EPERM;