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>

5 files changed, 26 insertions, 62 deletions

diff --git a/drivers/char/drm/drmP.h b/drivers/char/drm/drmP.h
index c93985bb91a2..fedaf013f848 100644
--- a/drivers/char/drm/drmP.h
+++ b/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 */
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);
diff --git a/drivers/char/drm/drm_drv.c b/drivers/char/drm/drm_drv.c
index 3da72f7364f0..f9ecc8414b8a 100644
--- a/drivers/char/drm/drm_drv.c
+++ b/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 */
diff --git a/drivers/char/drm/drm_fops.c b/drivers/char/drm/drm_fops.c
index 51ccc82bf612..2bbf45d85c35 100644
--- a/drivers/char/drm/drm_fops.c
+++ b/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)
diff --git a/drivers/char/drm/drm_hashtab.h b/drivers/char/drm/drm_hashtab.h
index 40afec05bff8..9e19ef1814ba 100644
--- a/drivers/char/drm/drm_hashtab.h
+++ b/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;