From: Niklas Schnelle schnelle@linux.ibm.com
commit 9660dcbe0d9186976917c94bce4e69dbd8d7a974 upstream.
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 get_order(size).
Cc: stable@vger.kernel.org Fixes: 8010d74b9965 ("RDMA/mlx5: Split the WR setup out of mlx5_ib_update_xlt()") Link: https://lore.kernel.org/r/20210908081849.7948-1-schnelle@linux.ibm.com Signed-off-by: Niklas Schnelle schnelle@linux.ibm.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/infiniband/hw/mlx5/mr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- 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 *n
if (size > MLX5_SPARE_UMR_CHUNK) { size = MLX5_SPARE_UMR_CHUNK; - *nents = get_order(size) / ent_size; + *nents = size / ent_size; res = (void *)__get_free_pages(gfp_mask | __GFP_NOWARN, get_order(size)); if (res)