svcrdma: Change DMA mapping logic to avoid the page_address kernel API

There was logic in the send path that assumed that a page containing data
to send to the client has a KVA. This is not always the case and can result
in data corruption when page_address returns zero and we end up DMA mapping
zero.

This patch changes the bus mapping logic to avoid page_address() where
necessary and converts all calls from ib_dma_map_single to ib_dma_map_page
in order to keep the map/unmap calls symmetric.

Signed-off-by: Tom Tucker <tom@ogc.us>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 11 insertions, 7 deletions

diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 0194de814933..926bdb44f3de 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -263,9 +263,9 @@ static int fast_reg_read_chunks(struct svcxprt_rdma *xprt,
 	frmr->page_list_len = PAGE_ALIGN(byte_count) >> PAGE_SHIFT;
 	for (page_no = 0; page_no < frmr->page_list_len; page_no++) {
 		frmr->page_list->page_list[page_no] =
-			ib_dma_map_single(xprt->sc_cm_id->device,
-					  page_address(rqstp->rq_arg.pages[page_no]),
-					  PAGE_SIZE, DMA_FROM_DEVICE);
+			ib_dma_map_page(xprt->sc_cm_id->device,
+					rqstp->rq_arg.pages[page_no], 0,
+					PAGE_SIZE, DMA_FROM_DEVICE);
 		if (ib_dma_mapping_error(xprt->sc_cm_id->device,
 					 frmr->page_list->page_list[page_no]))
 			goto fatal_err;
@@ -309,17 +309,21 @@ static int rdma_set_ctxt_sge(struct svcxprt_rdma *xprt,
 			     int count)
 {
 	int i;
+	unsigned long off;
 
 	ctxt->count = count;
 	ctxt->direction = DMA_FROM_DEVICE;
 	for (i = 0; i < count; i++) {
 		ctxt->sge[i].length = 0; /* in case map fails */
 		if (!frmr) {
+			BUG_ON(0 == virt_to_page(vec[i].iov_base));
+			off = (unsigned long)vec[i].iov_base & ~PAGE_MASK;
 			ctxt->sge[i].addr =
-				ib_dma_map_single(xprt->sc_cm_id->device,
-						  vec[i].iov_base,
-						  vec[i].iov_len,
-						  DMA_FROM_DEVICE);
+				ib_dma_map_page(xprt->sc_cm_id->device,
+						virt_to_page(vec[i].iov_base),
+						off,
+						vec[i].iov_len,
+						DMA_FROM_DEVICE);
 			if (ib_dma_mapping_error(xprt->sc_cm_id->device,
 						 ctxt->sge[i].addr))
 				return -EINVAL;