On Mon, Aug 14, 2023 at 03:52:20PM +0530, Abhijit Gangurde wrote:
> Add a mutex lock to prevent race between controller ops initiated by
> the bus subsystem and the controller registration/unregistration.
>
> Signed-off-by: Abhijit Gangurde <abhijit.gangurde@amd.com>
> ---
> drivers/cdx/cdx.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/drivers/cdx/cdx.c b/drivers/cdx/cdx.c
> index 1c0f76cf4f15..50df061f4537 100644
> --- a/drivers/cdx/cdx.c
> +++ b/drivers/cdx/cdx.c
> @@ -72,6 +72,8 @@
>
> /* IDA for CDX controllers registered with the CDX bus */
> DEFINE_IDA(cdx_controller_ida);
> +/* Lock to protect controller ops */
> +static DEFINE_MUTEX(cdx_controller_lock);
>
> static char *compat_node_name = "xlnx,versal-net-cdx";
>
> @@ -396,6 +398,8 @@ static ssize_t rescan_store(const struct bus_type *bus,
> if (!val)
> return -EINVAL;
>
> + mutex_lock(&cdx_controller_lock);
> +
> /* Unregister all the devices on the bus */
> cdx_unregister_devices(&cdx_bus_type);
>
> @@ -415,6 +419,8 @@ static ssize_t rescan_store(const struct bus_type *bus,
> put_device(&pd->dev);
> }
>
> + mutex_unlock(&cdx_controller_lock);
> +
> return count;
> }
> static BUS_ATTR_WO(rescan);
> @@ -538,11 +544,13 @@ int cdx_register_controller(struct cdx_controller *cdx)
> return ret;
> }
>
> + mutex_lock(&cdx_controller_lock);
> cdx->id = ret;
>
> /* Scan all the devices */
> cdx->ops->scan(cdx);
> cdx->controller_registered = true;
> + mutex_unlock(&cdx_controller_lock);
>
> return 0;
> }
> @@ -553,9 +561,13 @@ void cdx_unregister_controller(struct cdx_controller *cdx)
> if (cdx->id >= MAX_CDX_CONTROLLERS)
> return;
>
> + mutex_lock(&cdx_controller_lock);
> +
> cdx->controller_registered = false;
> device_for_each_child(cdx->dev, NULL, cdx_unregister_device);
> ida_free(&cdx_controller_ida, cdx->id);
> +
> + mutex_unlock(&cdx_controller_lock);
> }
> EXPORT_SYMBOL_GPL(cdx_unregister_controller);
>
> --
> 2.25.1
>
Ah, now you lock things, that answers the question in patch 1...