Commit 6bc1a656 authored by Moshe Lazer's avatar Moshe Lazer Committed by Doug Ledford

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
......@@ -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;
......
......@@ -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);
......
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