X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=src%2Fmesa%2Fmain%2Fhash.c;h=b624e6ecac1537ed8851d83b8081eeab04f5bf2d;hb=67ffbbbb5db88f936d54bacab971d20e44a83da1;hp=b2cfc7a0ac257b7824e6d144dc2e6a002d646ac0;hpb=f63623779a44c677d8731cbd706a02a615e03b0f;p=mesa.git

diff --git a/src/mesa/main/hash.c b/src/mesa/main/hash.c
index b2cfc7a0ac2..b624e6ecac1 100644
--- a/src/mesa/main/hash.c
+++ b/src/mesa/main/hash.c
@@ -37,7 +37,7 @@
 
 #include "glheader.h"
 #include "imports.h"
-#include "glthread.h"
+#include "glapi/glthread.h"
 #include "hash.h"
 
 
@@ -63,6 +63,7 @@ struct _mesa_HashTable {
    struct HashEntry *Table[TABLE_SIZE];  /**< the lookup table */
    GLuint MaxKey;                        /**< highest key inserted so far */
    _glthread_Mutex Mutex;                /**< mutual exclusion lock */
+   _glthread_Mutex WalkMutex;            /**< for _mesa_HashWalk() */
    GLboolean InDeleteAll;                /**< Debug check */
 };
 
@@ -79,6 +80,7 @@ _mesa_NewHashTable(void)
    struct _mesa_HashTable *table = CALLOC_STRUCT(_mesa_HashTable);
    if (table) {
       _glthread_INIT_MUTEX(table->Mutex);
+      _glthread_INIT_MUTEX(table->WalkMutex);
    }
    return table;
 }
@@ -106,26 +108,23 @@ _mesa_DeleteHashTable(struct _mesa_HashTable *table)
             _mesa_problem(NULL,
                           "In _mesa_DeleteHashTable, found non-freed data");
          }
-	 _mesa_free(entry);
+	 free(entry);
 	 entry = next;
       }
    }
    _glthread_DESTROY_MUTEX(table->Mutex);
-   _mesa_free(table);
+   _glthread_DESTROY_MUTEX(table->WalkMutex);
+   free(table);
 }
 
 
 
 /**
- * Lookup an entry in the hash table.
- * 
- * \param table the hash table.
- * \param key the key.
- * 
- * \return pointer to user's data or NULL if key not in table
+ * Lookup an entry in the hash table, without locking.
+ * \sa _mesa_HashLookup
  */
-void *
-_mesa_HashLookup(const struct _mesa_HashTable *table, GLuint key)
+static INLINE void *
+_mesa_HashLookup_unlocked(struct _mesa_HashTable *table, GLuint key)
 {
    GLuint pos;
    const struct HashEntry *entry;
@@ -137,7 +136,7 @@ _mesa_HashLookup(const struct _mesa_HashTable *table, GLuint key)
    entry = table->Table[pos];
    while (entry) {
       if (entry->Key == key) {
-	 return entry->Data;
+         return entry->Data;
       }
       entry = entry->Next;
    }
@@ -145,6 +144,25 @@ _mesa_HashLookup(const struct _mesa_HashTable *table, GLuint key)
 }
 
 
+/**
+ * Lookup an entry in the hash table.
+ * 
+ * \param table the hash table.
+ * \param key the key.
+ * 
+ * \return pointer to user's data or NULL if key not in table
+ */
+void *
+_mesa_HashLookup(struct _mesa_HashTable *table, GLuint key)
+{
+   void *res;
+   assert(table);
+   _glthread_LOCK_MUTEX(table->Mutex);
+   res = _mesa_HashLookup_unlocked(table, key);
+   _glthread_UNLOCK_MUTEX(table->Mutex);
+   return res;
+}
+
 
 /**
  * Insert a key/pointer pair into the hash table.  
@@ -175,9 +193,11 @@ _mesa_HashInsert(struct _mesa_HashTable *table, GLuint key, void *data)
    for (entry = table->Table[pos]; entry; entry = entry->Next) {
       if (entry->Key == key) {
          /* replace entry's data */
+#if 0 /* not sure this check is always valid */
          if (entry->Data) {
             _mesa_problem(NULL, "Memory leak detected in _mesa_HashInsert");
          }
+#endif
 	 entry->Data = data;
          _glthread_UNLOCK_MUTEX(table->Mutex);
 	 return;
@@ -186,10 +206,12 @@ _mesa_HashInsert(struct _mesa_HashTable *table, GLuint key, void *data)
 
    /* alloc and insert new table entry */
    entry = MALLOC_STRUCT(HashEntry);
-   entry->Key = key;
-   entry->Data = data;
-   entry->Next = table->Table[pos];
-   table->Table[pos] = entry;
+   if (entry) {
+      entry->Key = key;
+      entry->Data = data;
+      entry->Next = table->Table[pos];
+      table->Table[pos] = entry;
+   }
 
    _glthread_UNLOCK_MUTEX(table->Mutex);
 }
@@ -235,7 +257,7 @@ _mesa_HashRemove(struct _mesa_HashTable *table, GLuint key)
          else {
             table->Table[pos] = entry->Next;
          }
-         _mesa_free(entry);
+         free(entry);
          _glthread_UNLOCK_MUTEX(table->Mutex);
 	 return;
       }
@@ -272,7 +294,7 @@ _mesa_HashDeleteAll(struct _mesa_HashTable *table,
       for (entry = table->Table[pos]; entry; entry = next) {
          callback(entry->Key, entry->Data, userData);
          next = entry->Next;
-         _mesa_free(entry);
+         free(entry);
       }
       table->Table[pos] = NULL;
    }
@@ -283,6 +305,11 @@ _mesa_HashDeleteAll(struct _mesa_HashTable *table,
 
 /**
  * Walk over all entries in a hash table, calling callback function for each.
+ * Note: we use a separate mutex in this function to avoid a recursive
+ * locking deadlock (in case the callback calls _mesa_HashRemove()) and to
+ * prevent multiple threads/contexts from getting tangled up.
+ * A lock-less version of this function could be used when the table will
+ * not be modified.
  * \param table  the hash table to walk
  * \param callback  the callback function
  * \param userData  arbitrary pointer to pass along to the callback
@@ -298,14 +325,16 @@ _mesa_HashWalk(const struct _mesa_HashTable *table,
    GLuint pos;
    ASSERT(table);
    ASSERT(callback);
-   _glthread_UNLOCK_MUTEX(table2->Mutex);
+   _glthread_LOCK_MUTEX(table2->WalkMutex);
    for (pos = 0; pos < TABLE_SIZE; pos++) {
-      struct HashEntry *entry;
-      for (entry = table->Table[pos]; entry; entry = entry->Next) {
+      struct HashEntry *entry, *next;
+      for (entry = table->Table[pos]; entry; entry = next) {
+         /* save 'next' pointer now in case the callback deletes the entry */
+         next = entry->Next;
          callback(entry->Key, entry->Data, userData);
       }
    }
-   _glthread_UNLOCK_MUTEX(table2->Mutex);
+   _glthread_UNLOCK_MUTEX(table2->WalkMutex);
 }
 
 
@@ -430,7 +459,7 @@ _mesa_HashFindFreeKeyBlock(struct _mesa_HashTable *table, GLuint numKeys)
       GLuint freeStart = 1;
       GLuint key;
       for (key = 1; key != maxKey; key++) {
-	 if (_mesa_HashLookup(table, key)) {
+	 if (_mesa_HashLookup_unlocked(table, key)) {
 	    /* darn, this key is already in use */
 	    freeCount = 0;
 	    freeStart = key+1;