[PATCH 3.16 052/133] IB/mlx5: Fix integer overflow when page_shift == 31

[Ben Hutchings]

3.16.51-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Ilya Lesokhin <ilyal@xxxxxxxxxxxx>

commit 7b4cdaae73ee833975a767cf54a3354d355b3f8d upstream.

Fix a bug where MR registration fails when mlx5_ib_cont_pages
indicates that the MR can be mapped using 2GB pages (page_shift == 31).

Fixes: e126ba97dba9 ("mlx5: Add driver for Mellanox Connect-IB adapters")
Signed-off-by: Ilya Lesokhin <ilyal@xxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/infiniband/hw/mlx5/mr.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -682,13 +682,14 @@ err_free:
 	return ERR_PTR(err);
 }
 
-static int get_octo_len(u64 addr, u64 len, int page_size)
+static int get_octo_len(u64 addr, u64 len, int page_shift)
 {
+	u64 page_size = 1ULL << page_shift;
 	u64 offset;
 	int npages;
 
 	offset = addr & (page_size - 1);
-	npages = ALIGN(len + offset, page_size) >> ilog2(page_size);
+	npages = ALIGN(len + offset, page_size) >> page_shift;
 	return (npages + 1) / 2;
 }
 
@@ -870,11 +871,11 @@ static struct mlx5_ib_mr *reg_create(str
 	in->seg.start_addr = cpu_to_be64(virt_addr);
 	in->seg.len = cpu_to_be64(length);
 	in->seg.bsfs_octo_size = 0;
-	in->seg.xlt_oct_size = cpu_to_be32(get_octo_len(virt_addr, length, 1 << page_shift));
+	in->seg.xlt_oct_size = cpu_to_be32(get_octo_len(virt_addr, length, page_shift));
 	in->seg.log2_page_size = page_shift;
 	in->seg.qpn_mkey7_0 = cpu_to_be32(0xffffff << 8);
 	in->xlat_oct_act_size = cpu_to_be32(get_octo_len(virt_addr, length,
-							 1 << page_shift));
+							 page_shift));
 	err = mlx5_core_create_mkey(&dev->mdev, &mr->mmr, in, inlen, NULL,
 				    NULL, NULL);
 	if (err) {