From: Logan Gunthorpe <logang@deltatee.com>
Date: Thu, 4 Oct 2018 15:27:42 -0600
Subject: IB/core: Ensure we map P2P memory correctly in
 rdma_rw_ctx_[init|destroy]()
Patch-mainline: v4.20-rc1
Git-commit: 50b7d22079f74571a0fa73420586a7ad1ffebe2f
References: bsc#1103992 FATE#326009

In order to use PCI P2P memory the pci_p2pmem_map_sg() function must be
called to map the correct PCI bus address.

To do this, check the first page in the scatter list to see if it is P2P
memory or not.  At the moment, scatter lists that contain P2P memory must
be homogeneous so if the first page is P2P the entire SGL should be P2P.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/core/rw.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

--- a/drivers/infiniband/core/rw.c
+++ b/drivers/infiniband/core/rw.c
@@ -12,6 +12,7 @@
  */
 #include <linux/moduleparam.h>
 #include <linux/slab.h>
+#include <linux/pci-p2pdma.h>
 #include <rdma/mr_pool.h>
 #include <rdma/rw.h>
 
@@ -280,7 +281,11 @@ int rdma_rw_ctx_init(struct rdma_rw_ctx
 	struct ib_device *dev = qp->pd->device;
 	int ret;
 
-	ret = ib_dma_map_sg(dev, sg, sg_cnt, dir);
+	if (is_pci_p2pdma_page(sg_page(sg)))
+		ret = pci_p2pdma_map_sg(dev->dma_device, sg, sg_cnt, dir);
+	else
+		ret = ib_dma_map_sg(dev, sg, sg_cnt, dir);
+
 	if (!ret)
 		return -ENOMEM;
 	sg_cnt = ret;
@@ -602,7 +607,9 @@ void rdma_rw_ctx_destroy(struct rdma_rw_
 		break;
 	}
 
-	ib_dma_unmap_sg(qp->pd->device, sg, sg_cnt, dir);
+	/* P2PDMA contexts do not need to be unmapped */
+	if (!is_pci_p2pdma_page(sg_page(sg)))
+		ib_dma_unmap_sg(qp->pd->device, sg, sg_cnt, dir);
 }
 EXPORT_SYMBOL(rdma_rw_ctx_destroy);