winsys/radeon: fix a race condition in initialization of radeon_winsys::screen

Create the screen in the winsys while the mutex is locked.
This also results in a nice code cleanup!

Reviewed-by: Michel Dänzer <[email protected]>
Reviewed-by: Christian König <[email protected]>

2 files changed, 21 insertions, 3 deletions

diff --git a/src/gallium/winsys/radeon/drm/radeon_drm_public.h b/src/gallium/winsys/radeon/drm/radeon_drm_public.h
index 4fc62f1a400..dfcaaa4b6ef 100644
--- a/src/gallium/winsys/radeon/drm/radeon_drm_public.h
+++ b/src/gallium/winsys/radeon/drm/radeon_drm_public.h
@@ -4,7 +4,11 @@
 #include "pipe/p_defines.h"
 
 struct radeon_winsys;
+struct pipe_screen;
 
-struct radeon_winsys *radeon_drm_winsys_create(int fd);
+typedef struct pipe_screen *(*radeon_screen_create_t)(struct radeon_winsys *);
+
+struct radeon_winsys *
+radeon_drm_winsys_create(int fd, radeon_screen_create_t screen_create);
 
 #endif
diff --git a/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c b/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c
index 07b3c05f2b7..0eb0c6a07b9 100644
--- a/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c
+++ b/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c
@@ -586,7 +586,8 @@ static bool radeon_winsys_unref(struct radeon_winsys *ws)
     return destroy;
 }
 
-PUBLIC struct radeon_winsys *radeon_drm_winsys_create(int fd)
+PUBLIC struct radeon_winsys *
+radeon_drm_winsys_create(int fd, radeon_screen_create_t screen_create)
 {
     struct radeon_drm_winsys *ws;
 
@@ -609,7 +610,6 @@ PUBLIC struct radeon_winsys *radeon_drm_winsys_create(int fd)
     }
 
     ws->fd = fd;
-    util_hash_table_set(fd_tab, intptr_to_pointer(fd), ws);
 
     if (!do_winsys_init(ws))
         goto fail;
@@ -652,6 +652,20 @@ PUBLIC struct radeon_winsys *radeon_drm_winsys_create(int fd)
     if (ws->num_cpus > 1 && debug_get_option_thread())
         ws->thread = pipe_thread_create(radeon_drm_cs_emit_ioctl, ws);
 
+    /* Create the screen at the end. The winsys must be initialized
+     * completely.
+     *
+     * Alternatively, we could create the screen based on "ws->gen"
+     * and link all drivers into one binary blob. */
+    ws->base.screen = screen_create(&ws->base);
+    if (!ws->base.screen) {
+        radeon_winsys_destroy(&ws->base);
+        pipe_mutex_unlock(fd_tab_mutex);
+        return NULL;
+    }
+
+    util_hash_table_set(fd_tab, intptr_to_pointer(fd), ws);
+
     /* We must unlock the mutex once the winsys is fully initialized, so that
      * other threads attempting to create the winsys from the same fd will
      * get a fully initialized winsys and not just half-way initialized. */