[PATCH rdma-next] RDMA/mlx5: Annotate lock dependency in unbinding slave port

[PATCH rdma-next] RDMA/mlx5: Annotate lock dependency in unbinding slave port

[Leon Romanovsky]

From: Leon Romanovsky <leonro@mellanox.com>

NULL-ing notifier_call is performed under protection
of mlx5_ib_multiport_mutex lock. Such protection is
not easily spotted and better to be guarded by lockdep
annotation.

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
---
Based on -rc commit: 23eaf3b5c1a7 ("RDMA/mlx5: Release locks during notifier unregister")
---
 drivers/infiniband/hw/mlx5/main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 7933534be931..63969484421c 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -5835,6 +5835,8 @@ static void mlx5_ib_unbind_slave_port(struct mlx5_ib_dev *ibdev,
 	int err;
 	int i;

+	lockdep_assert_held(&mlx5_ib_multiport_mutex);
+
 	mlx5_ib_cleanup_cong_debugfs(ibdev, port_num);

 	spin_lock(&port->mp.mpi_lock);
--
2.20.1

Re: [PATCH rdma-next] RDMA/mlx5: Annotate lock dependency in unbinding slave port

[Doug Ledford]

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On Thu, 2019-08-08 at 11:39 +0300, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@mellanox.com>
> 
> NULL-ing notifier_call is performed under protection
> of mlx5_ib_multiport_mutex lock. Such protection is
> not easily spotted and better to be guarded by lockdep
> annotation.
> 
> Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
> ---
> Based on -rc commit: 23eaf3b5c1a7 ("RDMA/mlx5: Release locks during
> notifier unregister")
> ---
>  drivers/infiniband/hw/mlx5/main.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/infiniband/hw/mlx5/main.c
> b/drivers/infiniband/hw/mlx5/main.c
> index 7933534be931..63969484421c 100644
> --- a/drivers/infiniband/hw/mlx5/main.c
> +++ b/drivers/infiniband/hw/mlx5/main.c
> @@ -5835,6 +5835,8 @@ static void mlx5_ib_unbind_slave_port(struct
> mlx5_ib_dev *ibdev,
>  	int err;
>  	int i;
> 
> +	lockdep_assert_held(&mlx5_ib_multiport_mutex);
> +
>  	mlx5_ib_cleanup_cong_debugfs(ibdev, port_num);
> 
>  	spin_lock(&port->mp.mpi_lock);
> --
> 2.20.1
> 

Hi Leon,

This patch needed to catch both the unbind and the bind/init routine as
they both require the multiport mutex be held.  Can you respin please?

-- 
Doug Ledford <dledford@redhat.com>
    GPG KeyID: B826A3330E572FDD
    Fingerprint = AE6B 1BDA 122B 23B4 265B  1274 B826 A333 0E57 2FDD

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Re: [PATCH rdma-next] RDMA/mlx5: Annotate lock dependency in unbinding slave port

[Leon Romanovsky]

On Mon, Aug 12, 2019 at 10:31:19AM -0400, Doug Ledford wrote:
> On Thu, 2019-08-08 at 11:39 +0300, Leon Romanovsky wrote:
> > From: Leon Romanovsky <leonro@mellanox.com>
> >
> > NULL-ing notifier_call is performed under protection
> > of mlx5_ib_multiport_mutex lock. Such protection is
> > not easily spotted and better to be guarded by lockdep
> > annotation.
> >
> > Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
> > ---
> > Based on -rc commit: 23eaf3b5c1a7 ("RDMA/mlx5: Release locks during
> > notifier unregister")
> > ---
> >  drivers/infiniband/hw/mlx5/main.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/infiniband/hw/mlx5/main.c
> > b/drivers/infiniband/hw/mlx5/main.c
> > index 7933534be931..63969484421c 100644
> > --- a/drivers/infiniband/hw/mlx5/main.c
> > +++ b/drivers/infiniband/hw/mlx5/main.c
> > @@ -5835,6 +5835,8 @@ static void mlx5_ib_unbind_slave_port(struct
> > mlx5_ib_dev *ibdev,
> >  	int err;
> >  	int i;
> >
> > +	lockdep_assert_held(&mlx5_ib_multiport_mutex);
> > +
> >  	mlx5_ib_cleanup_cong_debugfs(ibdev, port_num);
> >
> >  	spin_lock(&port->mp.mpi_lock);
> > --
> > 2.20.1
> >
>
> Hi Leon,
>
> This patch needed to catch both the unbind and the bind/init routine as
> they both require the multiport mutex be held.  Can you respin please?

It has comment "5889 /* The mlx5_ib_multiport_mutex should be held when
calling this function */", why do we need lockdep?

Just kidding, sending fixed patch now.

Thanks

>
> --
> Doug Ledford <dledford@redhat.com>
>     GPG KeyID: B826A3330E572FDD
>     Fingerprint = AE6B 1BDA 122B 23B4 265B  1274 B826 A333 0E57 2FDD