Vishal Verma wrote:
> The dax driver incorrectly used driver-core device locks to protect
> internal dax region and dax device configuration structures. Replace the
> device lock usage with a local rwsem, one each for dax region
> configuration and dax device configuration. As a result of this
> conversion, no device_lock() usage remains in dax/bus.c.
>
> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> Reported-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Vishal Verma <vishal.l.verma@xxxxxxxxx>
> ---
> drivers/dax/bus.c | 220 ++++++++++++++++++++++++++++++++++++++----------------
> 1 file changed, 157 insertions(+), 63 deletions(-)
>
> diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
> index 1ff1ab5fa105..cb148f74ceda 100644
> --- a/drivers/dax/bus.c
> +++ b/drivers/dax/bus.c
> @@ -12,6 +12,18 @@
>
> static DEFINE_MUTEX(dax_bus_lock);
>
> +/*
> + * All changes to the dax region configuration occur with this lock held
> + * for write.
> + */
> +DECLARE_RWSEM(dax_region_rwsem);
> +
> +/*
> + * All changes to the dax device configuration occur with this lock held
> + * for write.
> + */
> +DECLARE_RWSEM(dax_dev_rwsem);
> +
> #define DAX_NAME_LEN 30
> struct dax_id {
> struct list_head list;
> @@ -180,7 +192,7 @@ static u64 dev_dax_size(struct dev_dax *dev_dax)
> u64 size = 0;
> int i;
>
> - device_lock_assert(&dev_dax->dev);
> + WARN_ON_ONCE(!rwsem_is_locked(&dax_dev_rwsem));
Apologies for the late review, but...
All of these WARN_ON_ONCE() usages should be replaced with
lockdep_assert_held() and lockdep_assert_held_write() where appropriate.
