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>

1 files changed, 32 insertions, 36 deletions

diff --git a/drivers/char/drm/drm_bufs.c b/drivers/char/drm/drm_bufs.c
index 7775fb5dfb9b..4440257f33e4 100644
--- a/drivers/char/drm/drm_bufs.c
+++ b/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;
                 }