[PATCH v2] RDMA/rtrs: client: Fix clt_path::max_pages_per_mr calculation

[Honggang LI]

If device max_mr_size bits in the range [mr_page_shift+31:mr_page_shift]
are zero, the `min3` function will set clt_path::max_pages_per_mr to
zero.

`alloc_path_reqs` will pass zero, which is invalid, as the third parameter
to `ib_alloc_mr`.

v1 -> v2:
Correct the commit message and set max_pages_per_mr to U32_MAX
as Michael Gur suggested.
Fixes: 6a98d71daea1 ("RDMA/rtrs: client: main functionality")
Signed-off-by: Honggang LI <honggangli@xxxxxxx>
---
 drivers/infiniband/ulp/rtrs/rtrs-clt.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
index 71387811b281..e477d2c0ff35 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
@@ -1464,6 +1464,8 @@ static void query_fast_reg_mode(struct rtrs_clt_path *clt_path)
 	mr_page_shift      = max(12, ffs(ib_dev->attrs.page_size_cap) - 1);
 	max_pages_per_mr   = ib_dev->attrs.max_mr_size;
 	do_div(max_pages_per_mr, (1ull << mr_page_shift));
+	if ((u32)max_pages_per_mr == 0)
+		max_pages_per_mr = U32_MAX;
 	clt_path->max_pages_per_mr =
 		min3(clt_path->max_pages_per_mr, (u32)max_pages_per_mr,
 		     ib_dev->attrs.max_fast_reg_page_list_len);
-- 
2.52.0