libdrm_radeon: add atomic operation for cs allocation.section_rewrite

1 files changed, 2 insertions, 5 deletions

diff --git a/libdrm/radeon/radeon_cs.h b/libdrm/radeon/radeon_cs.h
index 45f7abad..1ee6e947 100644
--- a/libdrm/radeon/radeon_cs.h
+++ b/libdrm/radeon/radeon_cs.h
@@ -135,11 +135,8 @@ static inline int radeon_cs_write_reloc(struct radeon_cs *cs,
 static inline uint32_t  __radeon_cs_alloc_section(struct radeon_cs *cs,
 	uint32_t ndw)
 {
-    /* If we ever want to do parellel driver we need to change
-       this to atomic fetch and add operation. For now simple
-       read and add is enough. */
-    uint32_t begin = cs->cdw;
-    cs->cdw += ndw;
+    /* Atomic operation for threading */
+    uint32_t begin = __sync_fetch_and_add(&cs->cdw, ndw);
     /* Handle cs overflow */
     if (begin + ndw > cs->ndw) {
 	return (uint32_t)-ENOMEM;