drm: fix issue with handle lookup for a 0 handle

On 32-bit PPC a 0 handle is valid for AGP space, the 32/64 lookup
doesn't handle 0 correctly.

From: Ben Herrenschmidt <benh@kernel.crashing.org> and Paul Mackerras <paulus@samba.org>
Signed-off-by: Dave Airlie <airlied@linux.ie>

1 files changed, 32 insertions, 32 deletions

diff --git a/drivers/char/drm/drm_bufs.c b/drivers/char/drm/drm_bufs.c
index e0743ebbe4bd..8eff0736a94d 100644
--- a/drivers/char/drm/drm_bufs.c
+++ b/drivers/char/drm/drm_bufs.c
@@ -48,8 +48,8 @@ unsigned long drm_get_resource_len(drm_device_t *dev, unsigned int resource)
 }
 EXPORT_SYMBOL(drm_get_resource_len);
 
-static drm_local_map_t *drm_find_matching_map(drm_device_t *dev,
-                                              drm_local_map_t *map)
+static drm_map_list_t *drm_find_matching_map(drm_device_t *dev,
+                                             drm_local_map_t *map)
 {
         struct list_head *list;
 
@@ -57,7 +57,7 @@ static drm_local_map_t *drm_find_matching_map(drm_device_t *dev,
                 drm_map_list_t *entry = list_entry(list, drm_map_list_t, head);
                 if (entry->map && map->type == entry->map->type &&
                     entry->map->offset == map->offset) {
-                        return entry->map;
+                        return entry;
                 }
         }
 
@@ -114,14 +114,13 @@ static __inline__ unsigned int HandleID(unsigned long lhandle, drm_device_t *dev
  * type.  Adds the map to the map list drm_device::maplist. Adds MTRR's where
  * applicable and if supported by the kernel.
  */
-int drm_addmap(drm_device_t * dev, unsigned int offset,
-               unsigned int size, drm_map_type_t type,
-               drm_map_flags_t flags, drm_local_map_t ** map_ptr)
+int drm_addmap_core(drm_device_t * dev, unsigned int offset,
+                    unsigned int size, drm_map_type_t type,
+                    drm_map_flags_t flags, drm_map_list_t **maplist)
 {
         drm_map_t *map;
         drm_map_list_t *list;
         drm_dma_handle_t *dmah;
-        drm_local_map_t *found_map;
 
         map = drm_alloc( sizeof(*map), DRM_MEM_MAPS );
         if ( !map )
@@ -166,17 +165,17 @@ int drm_addmap(drm_device_t * dev, unsigned int offset,
                  * needing to be aware of it.  Therefore, we just return success
                  * when the server tries to create a duplicate map.
                  */
-                found_map = drm_find_matching_map(dev, map);
-                if (found_map != NULL) {
-                        if (found_map->size != map->size) {
+                list = drm_find_matching_map(dev, map);
+                if (list != NULL) {
+                        if (list->map->size != map->size) {
                                 DRM_DEBUG("Matching maps of type %d with "
                                    "mismatched sizes, (%ld vs %ld)\n",
-                                    map->type, map->size, found_map->size);
-                                found_map->size = map->size;
+                                    map->type, map->size, list->map->size);
+                                list->map->size = map->size;
                         }
 
                         drm_free(map, sizeof(*map), DRM_MEM_MAPS);
-                        *map_ptr = found_map;
+                        *maplist = list;
                         return 0;
                 }
 
@@ -264,9 +263,22 @@ int drm_addmap(drm_device_t * dev, unsigned int offset,
                                     : map->offset, dev);
         up(&dev->struct_sem);
 
-        *map_ptr = map;
+        *maplist = list;
         return 0;
 }
+
+int drm_addmap(drm_device_t *dev, unsigned int offset,
+               unsigned int size, drm_map_type_t type,
+               drm_map_flags_t flags, drm_local_map_t **map_ptr)
+{
+        drm_map_list_t *list;
+        int rc;
+
+        rc = drm_addmap_core(dev, offset, size, type, flags, &list);
+        if (!rc)
+                *map_ptr = list->map;
+        return rc;
+}
 EXPORT_SYMBOL(drm_addmap);
 
 int drm_addmap_ioctl(struct inode *inode, struct file *filp,
@@ -275,10 +287,9 @@ int drm_addmap_ioctl(struct inode *inode, struct file *filp,
         drm_file_t *priv = filp->private_data;
         drm_device_t *dev = priv->head->dev;
         drm_map_t map;
-        drm_map_t *map_ptr;
+        drm_map_list_t *maplist;
         drm_map_t __user *argp = (void __user *)arg;
         int err;
-        unsigned long handle = 0;
 
         if (!(filp->f_mode & 3))
                 return -EACCES; /* Require read/write */
@@ -287,26 +298,15 @@ int drm_addmap_ioctl(struct inode *inode, struct file *filp,
                 return -EFAULT;
         }
 
-        err = drm_addmap(dev, map.offset, map.size, map.type, map.flags,
-                         &map_ptr);
+        err = drm_addmap_core(dev, map.offset, map.size, map.type, map.flags,
+                              &maplist);
 
-        if (err) {
+        if (err) 
                 return err;
-        }
-
-        {
-                drm_map_list_t *_entry;
-                list_for_each_entry(_entry, &dev->maplist->head, head) {
-                        if (_entry->map == map_ptr)
-                                handle = _entry->user_token;
-                }
-                if (!handle)
-                        return -EFAULT;
-        }
 
-        if (copy_to_user(argp, map_ptr, sizeof(*map_ptr)))
+        if (copy_to_user(argp, maplist->map, sizeof(drm_map_t)))
                 return -EFAULT;
-        if (put_user(handle, &argp->handle))
+        if (put_user(maplist->user_token, &argp->handle))
                 return -EFAULT;
         return 0;
 }