Re: [PATCH 1/6] s390: zcrypt: make zcrypt_class constant

[Ricardo B. Marliere]

On  8 Mar 15:19, Harald Freudenberger wrote:
> On 2024-03-05 12:25, Ricardo B. Marliere wrote:
> > Since commit 43a7206b0963 ("driver core: class: make class_register()
> > take
> > a const *"), the driver core allows for struct class to be in read-only
> > memory, so move the zcrypt_class structure to be declared at build time
> > placing it into read-only memory, instead of having to be dynamically
> > allocated at boot time.
> > 
> > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > Suggested-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Ricardo B. Marliere <ricardo@xxxxxxxxxxxx>
> > ---
> >  drivers/s390/crypto/zcrypt_api.c | 33 +++++++++++++++++----------------
> >  1 file changed, 17 insertions(+), 16 deletions(-)
> > 
> > diff --git a/drivers/s390/crypto/zcrypt_api.c
> > b/drivers/s390/crypto/zcrypt_api.c
> > index e8742757085b..d0358bb6ccf2 100644
> > --- a/drivers/s390/crypto/zcrypt_api.c
> > +++ b/drivers/s390/crypto/zcrypt_api.c
> > @@ -116,7 +116,11 @@ EXPORT_SYMBOL(zcrypt_msgtype);
> > 
> >  struct zcdn_device;
> > 
> > -static struct class *zcrypt_class;
> > +static void zcdn_device_release(struct device *dev);
> > +static const struct class zcrypt_class = {
> > +	.name = ZCRYPT_NAME,
> > +	.dev_release = zcdn_device_release,
> > +};
> >  static dev_t zcrypt_devt;
> >  static struct cdev zcrypt_cdev;
> > 
> > @@ -139,7 +143,7 @@ static int zcdn_destroy(const char *name);
> >   */
> >  static inline struct zcdn_device *find_zcdndev_by_name(const char
> > *name)
> >  {
> > -	struct device *dev = class_find_device_by_name(zcrypt_class, name);
> > +	struct device *dev = class_find_device_by_name(&zcrypt_class, name);
> > 
> >  	return dev ? to_zcdn_dev(dev) : NULL;
> >  }
> > @@ -151,7 +155,7 @@ static inline struct zcdn_device
> > *find_zcdndev_by_name(const char *name)
> >   */
> >  static inline struct zcdn_device *find_zcdndev_by_devt(dev_t devt)
> >  {
> > -	struct device *dev = class_find_device_by_devt(zcrypt_class, devt);
> > +	struct device *dev = class_find_device_by_devt(&zcrypt_class, devt);
> > 
> >  	return dev ? to_zcdn_dev(dev) : NULL;
> >  }
> > @@ -405,7 +409,7 @@ static int zcdn_create(const char *name)
> >  		goto unlockout;
> >  	}
> >  	zcdndev->device.release = zcdn_device_release;
> > -	zcdndev->device.class = zcrypt_class;
> > +	zcdndev->device.class = &zcrypt_class;
> >  	zcdndev->device.devt = devt;
> >  	zcdndev->device.groups = zcdn_dev_attr_groups;
> >  	if (name[0])
> > @@ -2067,12 +2071,9 @@ static int __init zcdn_init(void)
> >  	int rc;
> > 
> >  	/* create a new class 'zcrypt' */
> > -	zcrypt_class = class_create(ZCRYPT_NAME);
> > -	if (IS_ERR(zcrypt_class)) {
> > -		rc = PTR_ERR(zcrypt_class);
> > +	rc = class_register(&zcrypt_class);
> > +	if (rc)
> >  		goto out_class_create_failed;
> > -	}
> > -	zcrypt_class->dev_release = zcdn_device_release;
> > 
> >  	/* alloc device minor range */
> >  	rc = alloc_chrdev_region(&zcrypt_devt,
> > @@ -2088,35 +2089,35 @@ static int __init zcdn_init(void)
> >  		goto out_cdev_add_failed;
> > 
> >  	/* need some class specific sysfs attributes */
> > -	rc = class_create_file(zcrypt_class, &class_attr_zcdn_create);
> > +	rc = class_create_file(&zcrypt_class, &class_attr_zcdn_create);
> >  	if (rc)
> >  		goto out_class_create_file_1_failed;
> > -	rc = class_create_file(zcrypt_class, &class_attr_zcdn_destroy);
> > +	rc = class_create_file(&zcrypt_class, &class_attr_zcdn_destroy);
> >  	if (rc)
> >  		goto out_class_create_file_2_failed;
> > 
> >  	return 0;
> > 
> >  out_class_create_file_2_failed:
> > -	class_remove_file(zcrypt_class, &class_attr_zcdn_create);
> > +	class_remove_file(&zcrypt_class, &class_attr_zcdn_create);
> >  out_class_create_file_1_failed:
> >  	cdev_del(&zcrypt_cdev);
> >  out_cdev_add_failed:
> >  	unregister_chrdev_region(zcrypt_devt, ZCRYPT_MAX_MINOR_NODES);
> >  out_alloc_chrdev_failed:
> > -	class_destroy(zcrypt_class);
> > +	class_unregister(&zcrypt_class);
> >  out_class_create_failed:
> >  	return rc;
> >  }
> > 
> >  static void zcdn_exit(void)
> >  {
> > -	class_remove_file(zcrypt_class, &class_attr_zcdn_create);
> > -	class_remove_file(zcrypt_class, &class_attr_zcdn_destroy);
> > +	class_remove_file(&zcrypt_class, &class_attr_zcdn_create);
> > +	class_remove_file(&zcrypt_class, &class_attr_zcdn_destroy);
> >  	zcdn_destroy_all();
> >  	cdev_del(&zcrypt_cdev);
> >  	unregister_chrdev_region(zcrypt_devt, ZCRYPT_MAX_MINOR_NODES);
> > -	class_destroy(zcrypt_class);
> > +	class_unregister(&zcrypt_class);
> >  }
> > 
> >  /*
> 
> Thanks Ricardo, nice work.
> The only thing I would do is to rename the label "out_class_create_failed"
> with "out_class_register_failed".

Ah, indeed. Thanks for catching that. I will wait for more feedback on
the other patches and send a v2 if required.

> 
> Who will pick this patch? As this is part of a bundle of fixes, Richardo
> do you have a way to push this into the kernel? Otherwise as the AP/zcrypt
> maintainer I would pick only this patch and forward it to the s390
> subsystem.

I have no ways of pushing this, sorry. The series is based on
s390/linux.git/for-next, so perhaps the s390 maintainers can pick this
one along with the others with your Acked-by: provided? :) 

Thank you,
-	Ricardo.


> 
> Acked-by: Harald Freudenberger <freude@xxxxxxxxxxxxx>
>