PCI/P2PDMA: Remove the DMA_VIRT_OPS hacks

Now that all users of dma_virt_ops are gone we can remove the workaround
for it in the PCI peer to peer code.

Link: https://lore.kernel.org/r/20201106181941.1878556-9-hch@lst.deSigned-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/pci/p2pdma.c

@@ -556,15 +556,6 @@ int pci_p2pdma_distance_many(struct pci_dev *provider, struct device **clients,
 		return -1;
 
 	for (i = 0; i < num_clients; i++) {
-#ifdef CONFIG_DMA_VIRT_OPS
-		if (clients[i]->dma_ops == &dma_virt_ops) {
-			if (verbose)
-				dev_warn(clients[i],
-					 "cannot be used for peer-to-peer DMA because the driver makes use of dma_virt_ops\n");
-			return -1;
-		}
-#endif
-
 		pci_client = find_parent_pci_dev(clients[i]);
 		if (!pci_client) {
 			if (verbose)
@@ -837,17 +828,6 @@ static int __pci_p2pdma_map_sg(struct pci_p2pdma_pagemap *p2p_pgmap,
 	phys_addr_t paddr;
 	int i;
 
-	/*
-	 * p2pdma mappings are not compatible with devices that use
-	 * dma_virt_ops. If the upper layers do the right thing
-	 * this should never happen because it will be prevented
-	 * by the check in pci_p2pdma_distance_many()
-	 */
-#ifdef CONFIG_DMA_VIRT_OPS
-	if (WARN_ON_ONCE(dev->dma_ops == &dma_virt_ops))
-		return 0;
-#endif
-
 	for_each_sg(sg, s, nents, i) {
 		paddr = sg_phys(s);