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Commit 6bc1a656 authored by Moshe Lazer's avatar Moshe Lazer Committed by Doug Ledford
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IB/mlx5: Resolve soft lock on massive reg MRs 



When calling reg_mr of large MRs (e.g. 4GB) from multiple processes
and MR caches can't supply the required amount of MRs the slow-path
of MR allocation may be used. In this case we need to serialize the
slow-path between the processes to avoid soft lock.

Fixes: e126ba97 ('mlx5: Add driver for Mellanox Connect-IB adapters')
Signed-off-by: default avatarMoshe Lazer <moshel@mellanox.com>
Signed-off-by: default avatarMaor Gottlieb <maorg@mellanox.com>
Reviewed-by: default avatarEli Cohen <eli@mellanox.com>
Signed-off-by: default avatarLeon Romanovsky <leon@kernel.org>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent 16b0e069

drivers/infiniband/hw/mlx5/mlx5_ib.h

+2 −0
Original line number Diff line number Diff line
@@ -626,6 +626,8 @@ struct mlx5_ib_dev { 
	struct mlx5_ib_resources	devr;

	struct mlx5_mr_cache		cache;

	struct timer_list		delay_timer;

	/* Prevents soft lock on massive reg MRs */

	struct mutex			slow_path_mutex;

	int				fill_delay;

#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING

	struct ib_odp_caps	odp_caps;

drivers/infiniband/hw/mlx5/mr.c

+5 −1
Original line number Diff line number Diff line
@@ -610,6 +610,7 @@ int mlx5_mr_cache_init(struct mlx5_ib_dev *dev) 
	int err;

	int i;



	mutex_init(&dev->slow_path_mutex);

	cache->wq = alloc_ordered_workqueue("mkey_cache", WQ_MEM_RECLAIM);

	if (!cache->wq) {

		mlx5_ib_warn(dev, "failed to create work queue\n");
@@ -1182,9 +1183,12 @@ struct ib_mr *mlx5_ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length, 
		goto error;

	}



	if (!mr)

	if (!mr) {

		mutex_lock(&dev->slow_path_mutex);

		mr = reg_create(NULL, pd, virt_addr, length, umem, ncont,

				page_shift, access_flags);

		mutex_unlock(&dev->slow_path_mutex);

	}



	if (IS_ERR(mr)) {

		err = PTR_ERR(mr);