[PATCH 6.12 340/567] RDMA/rtrs: Fix clt_path::max_pages_per_mr calculation

Greg Kroah-Hartman
2026-01-06T17:33:04Z

From: Honggang LI <honggangli@163.com>

[ Upstream commit 43bd09d5b750f700499ae8ec45fd41a4c48673e6 ]

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`.

Fixes: 6a98d71daea1 ("RDMA/rtrs: client: main functionality")
Signed-off-by: Honggang LI <honggangli@163.com>
Link: https://patch.msgid.link/20251229025617.13241-1-honggangli@163.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/infiniband/ulp/rtrs/rtrs-clt.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
index 71387811b281..2b397a544cb9 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
@@ -1464,6 +1464,7 @@ 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));
+ max_pages_per_mr = min_not_zero((u32)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);
--
2.51.0