int svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset,
u32 required_bytes, u8 * copy_from_here);
int svm_fifo_dequeue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_here);
int svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset,
u32 required_bytes, u8 * copy_from_here);
int svm_fifo_dequeue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_here);