[PATCH i-g-t] lib/intel_allocator: protect binding for multithreaded tests

[Zbigniew Kempczyński]

Upcoming render-copy stress test reveals problem where multiple
threads enter binding code. Before binding/unbinding threads calls
alloc/free which collects operations to be executed in single vm_bind
ioctl. If first thread which fetches all binding operations from the
allocator will be interleaved by second thread which in turn sees no
operations are necessary to complete, it will start to execute jobs
without properly bounded offsets in the vm (it thinks addresses are
already there as there's no operations in the allocator).

Avoid this situation by migrating mutex lock to the place where thread
performing binding will finish its job. This will ensure any other
threads will wait until all binding operations are completed.

Signed-off-by: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
Cc: Francois Dugast <francois.dugast at intel.com>
---
 lib/intel_allocator.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/intel_allocator.c b/lib/intel_allocator.c
index 341db2a502..d22c70f1f7 100644
--- a/lib/intel_allocator.c
+++ b/lib/intel_allocator.c
@@ -1535,10 +1535,11 @@ static void __xe_op_bind(struct ahnd_info *ainfo, uint32_t sync_in, uint32_t syn
 			igt_map_remove(ainfo->bind_map, &obj->handle,
 				       map_entry_free_func);
 	}
-	pthread_mutex_unlock(&ainfo->bind_map_mutex);
 
 	xe_bind_unbind_async(ainfo->fd, ainfo->vm, 0, &obj_list, sync_in, sync_out);
 
+	pthread_mutex_unlock(&ainfo->bind_map_mutex);
+
 	igt_list_for_each_entry_safe(entry, tmp, &obj_list, link) {
 		igt_list_del(&entry->link);
 		free(entry);
-- 
2.34.1