From 296e3a2aad09d328f22e54655c3d736033fe1ae8 Mon Sep 17 00:00:00 2001
From: Moni Shoua <monis@mellanox.com>
Date: Tue, 23 Jul 2019 09:57:30 +0300
Subject: [PATCH 1/1] IB/mlx5: Prevent concurrent MR updates during
Git-commit: 296e3a2aad09d328f22e54655c3d736033fe1ae8
Patch-mainline: v5.10-rc1
References: bsc#1111666
invalidation
The device requires that memory registration work requests that update the
address translation table of a MR will be fenced if posted together. This
scenario can happen when address ranges are invalidated by the mmu in
separate concurrent calls to the invalidation callback.
We prefer to block concurrent address updates for a single MR over fencing
since making the decision if a WQE needs fencing will be more expensive
and fencing all WQEs is a too radical choice.
Further, it isn't clear that this code can even run safely concurrently,
so a lock is a safer choice.
Fixes: b4cfe447d47b ("IB/mlx5: Implement on demand paging by adding support for MMU notifiers")
Link: https://lore.kernel.org/r/20190723065733.4899-8-leon@kernel.org
Signed-off-by: Moni Shoua <monis@mellanox.com>
Reviewed-by: Artemy Kovalyov <artemyko@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Nicolas Morey-Chaisemartin <nmoreychaisemartin@suse.com>
---
drivers/infiniband/hw/mlx5/odp.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/infiniband/hw/mlx5/odp.c b/drivers/infiniband/hw/mlx5/odp.c
index 36ba901cc9a5..81da82050d05 100644
--- a/drivers/infiniband/hw/mlx5/odp.c
+++ b/drivers/infiniband/hw/mlx5/odp.c
@@ -246,7 +246,7 @@ void mlx5_ib_invalidate_range(struct ib_umem_odp *umem_odp, unsigned long start,
* overwrite the same MTTs. Concurent invalidations might race us,
* but they will write 0s as well, so no difference in the end result.
*/
-
+ mutex_lock(&umem_odp->umem_mutex);
for (addr = start; addr < end; addr += BIT(umem->page_shift)) {
idx = (addr - ib_umem_start(umem)) >> umem->page_shift;
/*
@@ -278,6 +278,7 @@ void mlx5_ib_invalidate_range(struct ib_umem_odp *umem_odp, unsigned long start,
idx - blk_start_idx + 1, 0,
MLX5_IB_UPD_XLT_ZAP |
MLX5_IB_UPD_XLT_ATOMIC);
+ mutex_unlock(&umem_odp->umem_mutex);
/*
* We are now sure that the device will not access the
* memory. We can safely unmap it, and mark it as dirty if
--
2.29.2