Commit ad2d3ef4 authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

RDMA/mlx5: Lock access to ent->available_mrs/limit when doing queue_work 

Accesses to these members needs to be locked. There is no reason not to
hold a spinlock while calling queue_work(), so move the tests into a
helper and always call it under lock.

The helper should be called when available_mrs is adjusted.

Link: https://lore.kernel.org/r/20200310082238.239865-10-leon@kernel.org


Signed-off-by: default avatarLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent a1d8854a

drivers/infiniband/hw/mlx5/mr.c

+25 −15
Original line number Diff line number Diff line
@@ -134,6 +134,10 @@ static void create_mkey_callback(int status, struct mlx5_async_work *context) 
	list_add_tail(&mr->list, &ent->head);

	ent->available_mrs++;

	ent->total_mrs++;

	/*

	 * Creating is always done in response to some demand, so do not call

	 * queue_adjust_cache_locked().

	 */

	spin_unlock_irqrestore(&ent->lock, flags);



	if (!completion_done(&ent->compl))
@@ -367,6 +371,20 @@ static int someone_adding(struct mlx5_mr_cache *cache) 
	return 0;

}



/*

 * Check if the bucket is outside the high/low water mark and schedule an async

 * update. The cache refill has hysteresis, once the low water mark is hit it is

 * refilled up to the high mark.

 */

static void queue_adjust_cache_locked(struct mlx5_cache_ent *ent)

{

	lockdep_assert_held(&ent->lock);



	if (ent->available_mrs < ent->limit ||

	    ent->available_mrs > 2 * ent->limit)

		queue_work(ent->dev->cache.wq, &ent->work);

}



static void __cache_work_func(struct mlx5_cache_ent *ent)

{

	struct mlx5_ib_dev *dev = ent->dev;
@@ -462,9 +480,8 @@ struct mlx5_ib_mr *mlx5_mr_cache_alloc(struct mlx5_ib_dev *dev, 
					      list);

			list_del(&mr->list);

			ent->available_mrs--;

			queue_adjust_cache_locked(ent);

			spin_unlock_irq(&ent->lock);

			if (ent->available_mrs < ent->limit)

				queue_work(cache->wq, &ent->work);

			return mr;

		}

	}
@@ -487,14 +504,12 @@ static struct mlx5_ib_mr *alloc_cached_mr(struct mlx5_cache_ent *req_ent) 
					      list);

			list_del(&mr->list);

			ent->available_mrs--;

			queue_adjust_cache_locked(ent);

			spin_unlock_irq(&ent->lock);

			if (ent->available_mrs < ent->limit)

				queue_work(dev->cache.wq, &ent->work);

			break;

		}

		queue_adjust_cache_locked(ent);

		spin_unlock_irq(&ent->lock);



		queue_work(dev->cache.wq, &ent->work);

	}



	if (!mr)
@@ -516,7 +531,6 @@ static void detach_mr_from_cache(struct mlx5_ib_mr *mr) 
void mlx5_mr_cache_free(struct mlx5_ib_dev *dev, struct mlx5_ib_mr *mr)

{

	struct mlx5_cache_ent *ent = mr->cache_ent;

	int shrink = 0;



	if (!ent)

		return;
@@ -524,20 +538,14 @@ void mlx5_mr_cache_free(struct mlx5_ib_dev *dev, struct mlx5_ib_mr *mr) 
	if (mlx5_mr_cache_invalidate(mr)) {

		detach_mr_from_cache(mr);

		destroy_mkey(dev, mr);

		if (ent->available_mrs < ent->limit)

			queue_work(dev->cache.wq, &ent->work);

		return;

	}



	spin_lock_irq(&ent->lock);

	list_add_tail(&mr->list, &ent->head);

	ent->available_mrs++;

	if (ent->available_mrs > 2 * ent->limit)

		shrink = 1;

	queue_adjust_cache_locked(ent);

	spin_unlock_irq(&ent->lock);



	if (shrink)

		queue_work(dev->cache.wq, &ent->work);

}



static void clean_keys(struct mlx5_ib_dev *dev, int c)
@@ -653,7 +661,9 @@ int mlx5_mr_cache_init(struct mlx5_ib_dev *dev) 
			ent->limit = dev->mdev->profile->mr_cache[i].limit;

		else

			ent->limit = 0;

		queue_work(cache->wq, &ent->work);

		spin_lock_irq(&ent->lock);

		queue_adjust_cache_locked(ent);

		spin_unlock_irq(&ent->lock);

	}



	mlx5_mr_cache_debugfs_init(dev);

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