Patch "IB/mlx5: Avoid system crash when enabling many VFs" has been added to the 4.9-stable tree

Patch "IB/mlx5: Avoid system crash when enabling many VFs" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    IB/mlx5: Avoid system crash when enabling many VFs

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ib-mlx5-avoid-system-crash-when-enabling-many-vfs.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From afd02cd3a9b6c04b41d946b5d7f6e17b3fc30c6b Mon Sep 17 00:00:00 2001
From: Eli Cohen <eli@mellanox.com>
Date: Sun, 27 Nov 2016 15:18:21 +0200
Subject: IB/mlx5: Avoid system crash when enabling many VFs

From: Eli Cohen <eli@mellanox.com>

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>

---
 drivers/infiniband/hw/mlx5/mr.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- 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_de
 		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;


Patches currently in stable-queue which might be from eli@mellanox.com are

queue-4.9/ib-mlx5-avoid-system-crash-when-enabling-many-vfs.patch
queue-4.9/ib-mlx5-wait-for-all-async-command-completions-to-complete.patch
queue-4.9/ib-mlx5-fix-reported-max-sge-calculation.patch