On 2021-03-12 7:36 p.m., Ira Weiny wrote: > On Thu, Mar 11, 2021 at 04:31:37PM -0700, Logan Gunthorpe wrote: > >> +int dma_pci_p2pdma_supported(struct device *dev) > ^^^ > bool? Sure. > >> +{ >> + const struct dma_map_ops *ops = get_dma_ops(dev); >> + >> + return !ops || ops->flags & DMA_F_PCI_P2PDMA_SUPPORTED; > > Is this logic correct? I would have expected. > > return (ops && ops->flags & DMA_F_PCI_P2PDMA_SUPPORTED); If ops is NULL then the operations in kernel/dma/direct.c are used and support is added to those in patch 6. So it is correct as written. Logan