drm: move drm authentication to new generic hash table.

Fix drm_remove_magic potential memory leak / corruption. Move drm
authentication token hashing to new generic hash table implementation.
Signed-off-by: Dave Airlie <airlied@linux.ie>

drivers/char/drm/drmP.h

@@ -105,7 +105,7 @@
 #define DRM_DEBUG_CODE 2	  /**< Include debugging code if > 1, then
 				     also include looping detection. */
 
-#define DRM_HASH_SIZE	      16 /**< Size of key hash table. Must be power of 2. */
+#define DRM_MAGIC_HASH_ORDER  4  /**< Size of key hash table. Must be power of 2. */
 #define DRM_KERNEL_CONTEXT    0	 /**< Change drm_resctx if changed */
 #define DRM_RESERVED_CONTEXTS 1	 /**< Change drm_resctx if changed */
 #define DRM_LOOPING_LIMIT     5000000
@@ -277,7 +277,8 @@ typedef struct drm_devstate {
 } drm_devstate_t;
 
 typedef struct drm_magic_entry {
-	drm_magic_t magic;
+	drm_hash_item_t hash_item;
+	struct list_head head;
 	struct drm_file *priv;
 	struct drm_magic_entry *next;
 } drm_magic_entry_t;
@@ -653,7 +654,8 @@ typedef struct drm_device {
 	/*@{ */
 	drm_file_t *file_first;		/**< file list head */
 	drm_file_t *file_last;		/**< file list tail */
-	drm_magic_head_t magiclist[DRM_HASH_SIZE];	/**< magic hash table */
+	drm_open_hash_t magiclist;	/**< magic hash table */
+	struct list_head magicfree;
 	/*@} */
 
 	/** \name Memory management */

drivers/char/drm/drm_auth.c

@@ -35,20 +35,6 @@
 
 #include "drmP.h"
 
-/**
- * Generate a hash key from a magic.
- *
- * \param magic magic.
- * \return hash key.
- *
- * The key is the modulus of the hash table size, #DRM_HASH_SIZE, which must be
- * a power of 2.
- */
-static int drm_hash_magic(drm_magic_t magic)
-{
-	return magic & (DRM_HASH_SIZE - 1);
-}
-
 /**
  * Find the file with the given magic number.
  *
@@ -63,14 +49,12 @@ static drm_file_t *drm_find_file(drm_device_t * dev, drm_magic_t magic)
 {
 	drm_file_t *retval = NULL;
 	drm_magic_entry_t *pt;
-	int hash = drm_hash_magic(magic);
+	drm_hash_item_t *hash;
 
 	mutex_lock(&dev->struct_mutex);
-	for (pt = dev->magiclist[hash].head; pt; pt = pt->next) {
-		if (pt->magic == magic) {
-			retval = pt->priv;
-			break;
-		}
+	if (!drm_ht_find_item(&dev->magiclist, (unsigned long)magic, &hash)) {
+		pt = drm_hash_entry(hash, drm_magic_entry_t, hash_item);
+		retval = pt->priv;
 	}
 	mutex_unlock(&dev->struct_mutex);
 	return retval;
@@ -90,28 +74,20 @@ static drm_file_t *drm_find_file(drm_device_t * dev, drm_magic_t magic)
 static int drm_add_magic(drm_device_t * dev, drm_file_t * priv,
 			 drm_magic_t magic)
 {
-	int hash;
 	drm_magic_entry_t *entry;
 
 	DRM_DEBUG("%d\n", magic);
 
-	hash = drm_hash_magic(magic);
 	entry = drm_alloc(sizeof(*entry), DRM_MEM_MAGIC);
 	if (!entry)
 		return -ENOMEM;
 	memset(entry, 0, sizeof(*entry));
-	entry->magic = magic;
 	entry->priv = priv;
-	entry->next = NULL;
 
+	entry->hash_item.key = (unsigned long)magic;
 	mutex_lock(&dev->struct_mutex);
-	if (dev->magiclist[hash].tail) {
-		dev->magiclist[hash].tail->next = entry;
-		dev->magiclist[hash].tail = entry;
-	} else {
-		dev->magiclist[hash].head = entry;
-		dev->magiclist[hash].tail = entry;
-	}
+	drm_ht_insert_item(&dev->magiclist, &entry->hash_item);
+	list_add_tail(&entry->head, &dev->magicfree);
 	mutex_unlock(&dev->struct_mutex);
 
 	return 0;
@@ -128,29 +104,19 @@ static int drm_add_magic(drm_device_t * dev, drm_file_t * priv,
  */
 static int drm_remove_magic(drm_device_t * dev, drm_magic_t magic)
 {
-	drm_magic_entry_t *prev = NULL;
 	drm_magic_entry_t *pt;
-	int hash;
+	drm_hash_item_t *hash;
 
 	DRM_DEBUG("%d\n", magic);
-	hash = drm_hash_magic(magic);
 
 	mutex_lock(&dev->struct_mutex);
-	for (pt = dev->magiclist[hash].head; pt; prev = pt, pt = pt->next) {
-		if (pt->magic == magic) {
-			if (dev->magiclist[hash].head == pt) {
-				dev->magiclist[hash].head = pt->next;
-			}
-			if (dev->magiclist[hash].tail == pt) {
-				dev->magiclist[hash].tail = prev;
-			}
-			if (prev) {
-				prev->next = pt->next;
-			}
-			mutex_unlock(&dev->struct_mutex);
-			return 0;
-		}
+	if (drm_ht_find_item(&dev->magiclist, (unsigned long)magic, &hash)) {
+		mutex_unlock(&dev->struct_mutex);
+		return -EINVAL;
 	}
+	pt = drm_hash_entry(hash, drm_magic_entry_t, hash_item);
+	drm_ht_remove_item(&dev->magiclist, hash);
+	list_del(&pt->head);
 	mutex_unlock(&dev->struct_mutex);
 
 	drm_free(pt, sizeof(*pt), DRM_MEM_MAGIC);

drivers/char/drm/drm_drv.c

@@ -155,12 +155,10 @@ int drm_lastclose(drm_device_t * dev)
 	del_timer(&dev->timer);
 
 	/* Clear pid list */
-	for (i = 0; i < DRM_HASH_SIZE; i++) {
-		for (pt = dev->magiclist[i].head; pt; pt = next) {
-			next = pt->next;
-			drm_free(pt, sizeof(*pt), DRM_MEM_MAGIC);
-		}
-		dev->magiclist[i].head = dev->magiclist[i].tail = NULL;
+	list_for_each_entry_safe(pt, next, &dev->magicfree, head) {
+		list_del(&pt->head);
+		drm_ht_remove_item(&dev->magiclist, &pt->hash_item);
+		drm_free(pt, sizeof(*pt), DRM_MEM_MAGIC);
 	}
 
 	/* Clear AGP information */

drivers/char/drm/drm_fops.c

@@ -72,10 +72,8 @@ static int drm_setup(drm_device_t * dev)
 	for (i = 0; i < ARRAY_SIZE(dev->counts); i++)
 		atomic_set(&dev->counts[i], 0);
 
-	for (i = 0; i < DRM_HASH_SIZE; i++) {
-		dev->magiclist[i].head = NULL;
-		dev->magiclist[i].tail = NULL;
-	}
+	drm_ht_create(&dev->magiclist, DRM_MAGIC_HASH_ORDER);
+	INIT_LIST_HEAD(&dev->magicfree);
 
 	dev->ctxlist = drm_alloc(sizeof(*dev->ctxlist), DRM_MEM_CTXLIST);
 	if (dev->ctxlist == NULL)

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) container_of(_ptr, _type, _member)
+#define drm_hash_entry(_ptr, _type, _member) list_entry(_ptr, _type, _member)
 
 typedef struct drm_hash_item{
 	struct hlist_node head;