linux-kernel - Re: [PATCH] s390: crypto make ap

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Date:   Mon, 13 Feb 2017 13:03:20 +0100
From:   Harald Freudenberger <freude@...ux.vnet.ibm.com>
To:     Paul Gortmaker <paul.gortmaker@...driver.com>,
        linux-kernel@...r.kernel.org
Cc:     Harald Freudenberger <freude@...ibm.com>,
        Martin Schwidefsky <schwidefsky@...ibm.com>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        linux-s390@...r.kernel.org
Subject: Re: [PATCH] s390: crypto make ap_bus explicitly non-modular

On 02/09/2017 03:48 PM, Paul Gortmaker wrote:
> The Makefile in drivers/s390 has:
>
> 	obj-y += cio/ block/ char/ crypto/ net/ scsi/ virtio/
>
> ..and the Makefile in crypto/ has:
>
> 	ap-objs := ap_bus.o ap_card.o ap_queue.o
>
> ...meaning that it currently is not being built as a module by anyone.
>
> Lets remove the modular code that is essentially orphaned, so that
> when reading the driver there is no doubt it is builtin-only.
>
> Since module_init translates to device_initcall in the non-modular
> case, the init ordering remains unchanged with this commit.
>
> Also note that MODULE_ALIAS is a no-op for non-module builds.
>
> We also delete the MODULE_LICENSE tag etc. since all that information
> is already contained at the top of the file in the comments.
>
> We replace module.h with moduleparam.h since the file does declare
> some module parameters even though it is not modular itself.
>
> Cc: Harald Freudenberger <freude@...ibm.com>
> Cc: Martin Schwidefsky <schwidefsky@...ibm.com>
> Cc: Heiko Carstens <heiko.carstens@...ibm.com>
> Cc: linux-s390@...r.kernel.org
> Signed-off-by: Paul Gortmaker <paul.gortmaker@...driver.com>
> ---
>  drivers/s390/crypto/ap_bus.c | 54 +++-----------------------------------------
>  1 file changed, 3 insertions(+), 51 deletions(-)
>
> diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
> index 5fa699192864..7183a316f9be 100644
> --- a/drivers/s390/crypto/ap_bus.c
> +++ b/drivers/s390/crypto/ap_bus.c
> @@ -27,7 +27,7 @@
>  #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
>
>  #include <linux/kernel_stat.h>
> -#include <linux/module.h>
> +#include <linux/moduleparam.h>
>  #include <linux/init.h>
>  #include <linux/delay.h>
>  #include <linux/err.h>
> @@ -54,16 +54,7 @@
>  #include "ap_debug.h"
>
>  /*
> - * Module description.
> - */
> -MODULE_AUTHOR("IBM Corporation");
> -MODULE_DESCRIPTION("Adjunct Processor Bus driver, " \
> -		   "Copyright IBM Corp. 2006, 2012");
> -MODULE_LICENSE("GPL");
> -MODULE_ALIAS_CRYPTO("z90crypt");
> -
> -/*
> - * Module parameter
> + * Module parameters; note though this file itself isn't modular.
>   */
>  int ap_domain_index = -1;	/* Adjunct Processor Domain Index */
>  static DEFINE_SPINLOCK(ap_domain_lock);
> @@ -1270,43 +1261,4 @@ int __init ap_module_init(void)
>  	kfree(ap_configuration);
>  	return rc;
>  }
> -
> -/**
> - * ap_modules_exit(): The module termination code
> - *
> - * Terminates the module.
> - */
> -void ap_module_exit(void)
> -{
> -	int i;
> -
> -	initialised = false;
> -	ap_reset_domain();
> -	ap_poll_thread_stop();
> -	del_timer_sync(&ap_config_timer);
> -	hrtimer_cancel(&ap_poll_timer);
> -	tasklet_kill(&ap_tasklet);
> -
> -	/* first remove queue devices */
> -	bus_for_each_dev(&ap_bus_type, NULL, NULL,
> -			 __ap_queue_devices_unregister);
> -	/* now remove the card devices */
> -	bus_for_each_dev(&ap_bus_type, NULL, NULL,
> -			 __ap_card_devices_unregister);
> -
> -	/* remove bus attributes */
> -	for (i = 0; ap_bus_attrs[i]; i++)
> -		bus_remove_file(&ap_bus_type, ap_bus_attrs[i]);
> -	unregister_pm_notifier(&ap_power_notifier);
> -	root_device_unregister(ap_root_device);
> -	bus_unregister(&ap_bus_type);
> -	kfree(ap_configuration);
> -	unregister_reset_call(&ap_reset_call);
> -	if (ap_using_interrupts())
> -		unregister_adapter_interrupt(&ap_airq);
> -
> -	ap_debug_exit();
> -}
> -
> -module_init(ap_module_init);
> -module_exit(ap_module_exit);
> +device_initcall(ap_module_init);
Thanks Paul for this patch.
I am struggling with the change as I still like to build the ap device driver as a kernel module.
It makes the development cycle somewhat easier to have this possibility with just a oneline
change in the Makefile (replace obj-$(subst m,y,$(CONFIG_ZCRYPT)) += ap.o
with obj-$(CONFIG_ZCRYPT) += ap.o).

However, you are right. As the ap driver is official not supported as a module the module
code may get removed. Let me think about this some hours ...

regards H.Freudenberger