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From: Niklas Schnelle <>
To: Leon Romanovsky <>, Jason Gunthorpe <>,
	Doug Ledford <>
Subject: [PATCH 1/2] RDMA/mlx5: Fix number of allocated XLT entries
Date: Wed,  1 Sep 2021 13:26:24 +0200	[thread overview]
Message-ID: <> (raw)

In commit 8010d74b9965b ("RDMA/mlx5: Split the WR setup out of
mlx5_ib_update_xlt()") the allocation logic was split out of
mlx5_ib_update_xlt() and the logic was changed to enable better OOM
handling. Sadly this change introduced a miscalculation of the number of
entries that were actually allocated when under memory pressure where it
can actually become 0 which on s390 lets dma_map_single() fail.

It can also lead to corruption of the free pages list when the wrong
number of entries is used in the calculation of sg->length which is used
as argument for free_pages().

Fix this by using the allocation size instead of misusing

Fixes: 8010d74b9965b ("RDMA/mlx5: Split the WR setup out of mlx5_ib_update_xlt()")
Signed-off-by: Niklas Schnelle <>
 drivers/infiniband/hw/mlx5/mr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index 3f1c5a4f158b..19713cdd7b78 100644
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -1024,7 +1024,7 @@ static void *mlx5_ib_alloc_xlt(size_t *nents, size_t ent_size, gfp_t gfp_mask)
 	if (size > MLX5_SPARE_UMR_CHUNK) {
-		*nents = get_order(size) / ent_size;
+		*nents = size / ent_size;
 		res = (void *)__get_free_pages(gfp_mask | __GFP_NOWARN,
 		if (res)

             reply	other threads:[~2021-09-01 11:26 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-01 11:26 Niklas Schnelle [this message]
2021-09-01 11:26 ` [PATCH 2/2] RDMA/mlx5: Fix xlt_chunk_align calculation Niklas Schnelle

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