Subject: [PATCH mlx5-next 08/10] net/rds: Detect need of On-Demand-Paging memory registration

From: Leon Romanovsky <[email-masked]>
Date: Wed, 15 Jan 2020 14:43:38 +0200

From: Hans Westgaard Ry <[email-masked]>

Add code to check if memory intended for RDMA is FS-DAX-memory. RDS
will fail with error code EOPNOTSUPP if FS-DAX-memory is detected.

Signed-off-by: Hans Westgaard Ry <[email-masked]>
Signed-off-by: Leon Romanovsky <[email-masked]>
---
 net/rds/rdma.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/rds/rdma.c b/net/rds/rdma.c
index 916f5ec373d8..eb23c38ce2b3 100644
--- a/net/rds/rdma.c
+++ b/net/rds/rdma.c
@@ -156,11 +156,13 @@ void rds_rdma_drop_keys(struct rds_sock *rs)
 static int rds_pin_pages(unsigned long user_addr, unsigned int nr_pages,
 			struct page **pages, int write)
 {
+	unsigned int gup_flags = FOLL_LONGTERM;
 	int ret;

-	ret = get_user_pages_fast(user_addr, nr_pages, write ? FOLL_WRITE : 0,
-				  pages);
+	if (write)
+		gup_flags |= FOLL_WRITE;

+	ret = get_user_pages_fast(user_addr, nr_pages, gup_flags, pages);
 	if (ret >= 0 && ret < nr_pages) {
 		while (ret--)
 			put_page(pages[ret]);
--
2.20.1