Hi David and others, I've recently been refactoring the dma direct mapping and swiotlb code, and one odd thing I noticed is that the octeon and loongson swiotlb ops have mb() calls after basically all swiotlb calls. None of that is explained in either the earlier octeon dma map commits, nor the commit that added the octeon swiotlb support (b93b2abce497873be97d765b848e0a955d29f200), and neither in the loonsoon commit that apparently copy and pasted it (1299b0e05e106f621fff1504df5251f2a678097e). Can someone explain what these memory barrier are supposed to do?
