Re: [PATCH v17 20/22] sfc: create cxl region

[<dan.j.williams@intel.com>]

alejandro.lucero-palau@ wrote:
> From: Alejandro Lucero <alucerop@amd.com>
> 
> Use cxl api for creating a region using the endpoint decoder related to
> a DPA range.
> 
> Add a callback for unwinding sfc cxl initialization when the endpoint port
> is destroyed by potential cxl_acpi or cxl_mem modules removal.
> 
> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
> ---
>  drivers/net/ethernet/sfc/efx_cxl.c | 24 +++++++++++++++++++++++-
>  1 file changed, 23 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/sfc/efx_cxl.c b/drivers/net/ethernet/sfc/efx_cxl.c
> index ffbf0e706330..7365effe974e 100644
> --- a/drivers/net/ethernet/sfc/efx_cxl.c
> +++ b/drivers/net/ethernet/sfc/efx_cxl.c
> @@ -18,6 +18,16 @@
>  
>  #define EFX_CTPIO_BUFFER_SIZE	SZ_256M
>  
> +static void efx_release_cxl_region(void *priv_cxl)
> +{
> +	struct efx_probe_data *probe_data = priv_cxl;
> +	struct efx_cxl *cxl = probe_data->cxl;
> +
> +	iounmap(cxl->ctpio_cxl);

There is no synchronization here. If someone unbinds the a cxl_port
while the driver is using @ctpio_cxl, it looks it will cause a crash.

The loss of CXL connectivity after the driver has already committed to
it likely means that the whole driver needs to be shutdown, not just
this region cleanup.