r300g: fix a possible race when counting contexts

[mesa.git] / src / gallium / drivers / r300 / r300_context.c

diff --git a/src/gallium/drivers/r300/r300_context.c b/src/gallium/drivers/r300/r300_context.c
index a89bf7fac3176f138ceb18c3fd9c881f97b5a332..da6b0bb8aa7d02fb9835db7b4d488068449392b2 100644 (file)
--- a/src/gallium/drivers/r300/r300_context.c
+++ b/src/gallium/drivers/r300/r300_context.c
@@ -38,19 +38,21 @@
 static void r300_update_num_contexts(struct r300_screen *r300screen,
                                      int diff)
 {
+    pipe_mutex_lock(r300screen->num_contexts_mutex);
     if (diff > 0) {
-        p_atomic_inc(&r300screen->num_contexts);
+        r300screen->num_contexts++;
 
         if (r300screen->num_contexts > 1)
             util_slab_set_thread_safety(&r300screen->pool_buffers,
                                         UTIL_SLAB_MULTITHREADED);
     } else {
-        p_atomic_dec(&r300screen->num_contexts);
+        r300screen->num_contexts--;
 
         if (r300screen->num_contexts <= 1)
             util_slab_set_thread_safety(&r300screen->pool_buffers,
                                         UTIL_SLAB_SINGLETHREADED);
     }
+    pipe_mutex_unlock(r300screen->num_contexts_mutex);
 }
 
 static void r300_release_referenced_objects(struct r300_context *r300)