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>

1 files changed, 14 insertions, 48 deletions

diff --git a/drivers/char/drm/drm_auth.c b/drivers/char/drm/drm_auth.c
index 2a37586a7ee8..40cd262ca9e1 100644
--- a/drivers/char/drm/drm_auth.c
+++ b/drivers/char/drm/drm_auth.c
@@ -36,20 +36,6 @@
 #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.
  *
  * \param dev DRM device.
@@ -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);