[PATCH rdma-rc] RDMA/mlx5: Fix mkey cache WQ flush

[PATCH rdma-rc] RDMA/mlx5: Fix mkey cache WQ flush

[Leon Romanovsky]

From: Moshe Shemesh <moshe@nvidia.com>

The cited patch tries to ensure no pending works on the mkey cache
workqueue by disabling adding new works and call flush_workqueue().
But this workqueue also has delayed works which might still be pending
the delay time to be queued.

Add cancel_delayed_work() for the delayed works which waits to be queued
and then the flush_workqueue() will flush all works which are already
queued and running.

Fixes: 374012b00457 ("RDMA/mlx5: Fix mkey cache possible deadlock on cleanup")
Signed-off-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/infiniband/hw/mlx5/mr.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index 8a3762d9ff58..e0629898c3c0 100644
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -1026,11 +1026,13 @@ void mlx5_mkey_cache_cleanup(struct mlx5_ib_dev *dev)
 		return;
 
 	mutex_lock(&dev->cache.rb_lock);
+	cancel_delayed_work(&dev->cache.remove_ent_dwork);
 	for (node = rb_first(root); node; node = rb_next(node)) {
 		ent = rb_entry(node, struct mlx5_cache_ent, node);
 		xa_lock_irq(&ent->mkeys);
 		ent->disabled = true;
 		xa_unlock_irq(&ent->mkeys);
+		cancel_delayed_work(&ent->dwork);
 	}
 	mutex_unlock(&dev->cache.rb_lock);
 
-- 
2.41.0

Re: [PATCH rdma-rc] RDMA/mlx5: Fix mkey cache WQ flush

[Jason Gunthorpe]

On Wed, Oct 25, 2023 at 08:49:59PM +0300, Leon Romanovsky wrote:
> From: Moshe Shemesh <moshe@nvidia.com>
> 
> The cited patch tries to ensure no pending works on the mkey cache
> workqueue by disabling adding new works and call flush_workqueue().
> But this workqueue also has delayed works which might still be pending
> the delay time to be queued.
> 
> Add cancel_delayed_work() for the delayed works which waits to be queued
> and then the flush_workqueue() will flush all works which are already
> queued and running.
> 
> Fixes: 374012b00457 ("RDMA/mlx5: Fix mkey cache possible deadlock on cleanup")
> Signed-off-by: Moshe Shemesh <moshe@nvidia.com>
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
>  drivers/infiniband/hw/mlx5/mr.c | 2 ++
>  1 file changed, 2 insertions(+)

Applied to for-next, thanks

Jason