From d0b5c01bb446f87e94265b172c00f4e89829116d Mon Sep 17 00:00:00 2001
From: Shiraz Saleem <shiraz.saleem@intel.com>
Date: Thu, 4 Apr 2019 10:22:47 -0500
Subject: [PATCH] RDMA/umem: Use correct value for SG entries in
 sg_copy_to_buffer()

With page combining, the assumption that number of SG entries in umem SGL
equal to number of system pages in umem no longer holds.

umem->sg_nents tracks the SG entries in umem SGL. Use it in
sg_pcopy_to_buffer() as opposed to ib_umem_num_pages(umem).

Fixes: d10bcf947a3e ("RDMA/umem: Combine contiguous PAGE_SIZE regions in SGEs")
Reported-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
---
 drivers/infiniband/core/umem.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index d31f5e386c7d..7e912a91ec8e 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -381,8 +381,8 @@ int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
 		return -EINVAL;
 	}
 
-	ret = sg_pcopy_to_buffer(umem->sg_head.sgl, ib_umem_num_pages(umem),
-				 dst, length, offset + ib_umem_offset(umem));
+	ret = sg_pcopy_to_buffer(umem->sg_head.sgl, umem->sg_nents, dst, length,
+				 offset + ib_umem_offset(umem));
 
 	if (ret < 0)
 		return ret;
-- 
2.30.2