[PATCH 4.15 059/146] IB/mlx5: Fix incorrect size of klms in the memory region

[Greg Kroah-Hartman]

4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sergey Gorenko <sergeygo@xxxxxxxxxxxx>

commit da343b6d90e11132f1e917d865d88ee35d6e6d00 upstream.

The value of mr->ndescs greater than mr->max_descs is set in the
function mlx5_ib_sg_to_klms() if sg_nents is greater than
mr->max_descs. This is an invalid value and it causes the
following error when registering mr:

mlx5_0:dump_cqe:276:(pid 193): dump error cqe
00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000030: 00 00 00 00 0f 00 78 06 25 00 00 8b 08 1e 8f d3

Cc: <stable@xxxxxxxxxxxxxxx> # 4.5
Fixes: b005d3164713 ("mlx5: Add arbitrary sg list support")
Signed-off-by: Sergey Gorenko <sergeygo@xxxxxxxxxxxx>
Tested-by: Laurence Oberman <loberman@xxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/infiniband/hw/mlx5/mr.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -1813,7 +1813,6 @@ mlx5_ib_sg_to_klms(struct mlx5_ib_mr *mr
 
 	mr->ibmr.iova = sg_dma_address(sg) + sg_offset;
 	mr->ibmr.length = 0;
-	mr->ndescs = sg_nents;
 
 	for_each_sg(sgl, sg, sg_nents, i) {
 		if (unlikely(i >= mr->max_descs))
@@ -1825,6 +1824,7 @@ mlx5_ib_sg_to_klms(struct mlx5_ib_mr *mr
 
 		sg_offset = 0;
 	}
+	mr->ndescs = i;
 
 	if (sg_offset_p)
 		*sg_offset_p = sg_offset;