[lvc-project] [PATCH] RDMA/erdma: handle ib_umem_find_best_pgsz() return value

[Ваторопин Андрей]

From: Andrey Vatoropin <a.vatoropin at crpt.ru>

The ib_umem_find_best_pgsz function is necessary for obtaining the optimal
hardware page size. In the comment above, function has statement: 
"Drivers always supporting PAGE_SIZE or smaller will never see a 0 result."

But it's hard to prove this holds true for the erdma driver.

Similar to other drivers that use ib_umem_find_best_pgsz, it is essential 
to add an error handler to manage potential error situations in the future.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 155055771704 ("RDMA/erdma: Add verbs implementation")
Signed-off-by: Andrey Vatoropin <a.vatoropin at crpt.ru>
---
 drivers/infiniband/hw/erdma/erdma_verbs.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/infiniband/hw/erdma/erdma_verbs.c b/drivers/infiniband/hw/erdma/erdma_verbs.c
index 51d619edb6c5..7ad38fb84661 100644
--- a/drivers/infiniband/hw/erdma/erdma_verbs.c
+++ b/drivers/infiniband/hw/erdma/erdma_verbs.c
@@ -781,6 +781,10 @@ static int get_mtt_entries(struct erdma_dev *dev, struct erdma_mem *mem,
 	mem->page_size = ib_umem_find_best_pgsz(mem->umem, req_page_size, virt);
+	if (!mem->page_size) {
+		ret = -EINVAL;
+		goto error_ret;
+	}
 	mem->page_offset = start & (mem->page_size - 1);
 	mem->mtt_nents = ib_umem_num_dma_blocks(mem->umem, mem->page_size);
 	mem->page_cnt = mem->mtt_nents;
 	mem->mtt = erdma_create_mtt(dev, MTT_SIZE(mem->page_cnt),
 				    force_continuous);
-- 
2.43.0