IB/mlx5: Avoid system crash when enabling many VFs

commit afd02cd3a9b6c04b41d946b5d7f6e17b3fc30c6b upstream.

When enabling many VFs, the total amount of DMA mappings increase
significantly. This causes DMA allocations to take a lot of time
since they are serialized in the kernel.

As a result the driver enters into fatal condition due to
timeout and the system hangs. To recover from this we disable
MR cache for VFs.

PFs will still have a full cache and VFs cache can be manipulated
as usual after driver load.

Fixes: e126ba97dba9 ('mlx5: Add driver for Mellanox Connect-IB adapters')
Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index 4e9012463c37de6381cddde1c527e4c2ff6e84ae..501af9eab6ec8a57c1f0a15342297f9799a2fc59 100644 (file)
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -628,7 +628,8 @@ int mlx5_mr_cache_init(struct mlx5_ib_dev *dev)
                ent->order = i + 2;
                ent->dev = dev;
 
-               if (dev->mdev->profile->mask & MLX5_PROF_MASK_MR_CACHE)
+               if ((dev->mdev->profile->mask & MLX5_PROF_MASK_MR_CACHE) &&
+                   (mlx5_core_is_pf(dev->mdev)))
                        limit = dev->mdev->profile->mr_cache[i].limit;
                else
                        limit = 0;