hwcontext_vulkan: wait and signal semaphores when transferring to CUDA

Same as when downloading. Not sure why this isn't done, probably
because the CUDA code predates the sync mechanism we settled on.

libavutil/hwcontext_vulkan.c

@@ -3253,6 +3253,8 @@ static int vulkan_transfer_data_to_cuda(AVHWFramesContext *hwfc, AVFrame *dst,
     AVCUDADeviceContext *cuda_dev = cuda_cu->hwctx;
     AVCUDADeviceContextInternal *cu_internal = cuda_dev->internal;
     CudaFunctions *cu = cu_internal->cuda_dl;
+    CUDA_EXTERNAL_SEMAPHORE_WAIT_PARAMS s_w_par[AV_NUM_DATA_POINTERS] = { 0 };
+    CUDA_EXTERNAL_SEMAPHORE_SIGNAL_PARAMS s_s_par[AV_NUM_DATA_POINTERS] = { 0 };
 
     ret = CHECK_CU(cu->cuCtxPushCurrent(cuda_dev->cuda_ctx));
     if (ret < 0)
@@ -3268,6 +3270,13 @@ static int vulkan_transfer_data_to_cuda(AVHWFramesContext *hwfc, AVFrame *dst,
 
     dst_int = dst_f->internal;
 
+    ret = CHECK_CU(cu->cuWaitExternalSemaphoresAsync(dst_int->cu_sem, s_w_par,
+                                                     planes, cuda_dev->stream));
+    if (ret < 0) {
+        err = AVERROR_EXTERNAL;
+        goto fail;
+    }
+
     for (int i = 0; i < planes; i++) {
         CUDA_MEMCPY2D cpy = {
             .dstMemoryType = CU_MEMORYTYPE_DEVICE,
@@ -3292,6 +3301,13 @@ static int vulkan_transfer_data_to_cuda(AVHWFramesContext *hwfc, AVFrame *dst,
         }
     }
 
+    ret = CHECK_CU(cu->cuSignalExternalSemaphoresAsync(dst_int->cu_sem, s_s_par,
+                                                       planes, cuda_dev->stream));
+    if (ret < 0) {
+        err = AVERROR_EXTERNAL;
+        goto fail;
+    }
+
     CHECK_CU(cu->cuCtxPopCurrent(&dummy));
 
     av_log(hwfc, AV_LOG_VERBOSE, "Transfered Vulkan image to CUDA!\n");