2023-10-24 11:50:48

by Greg Kroah-Hartman

Subject: [PATCH] uacce: make uacce_class constant

Now that the driver core allows for struct class to be in read-only
memory, we should make all 'class' structures declared at build time
placing them into read-only memory, instead of having to be dynamically
allocated at runtime.

Cc: Zhangfei Gao <[email protected]>
Cc: Zhou Wang <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: [email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/misc/uacce/uacce.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
index 930c252753a0..bdc2e6fda782 100644
--- a/drivers/misc/uacce/uacce.c
+++ b/drivers/misc/uacce/uacce.c
@@ -7,10 +7,13 @@
#include <linux/slab.h>
#include <linux/uacce.h>

-static struct class *uacce_class;
static dev_t uacce_devt;
static DEFINE_XARRAY_ALLOC(uacce_xa);

+static const struct class uacce_class = {
+ .name = UACCE_NAME,
+};
+
/*
* If the parent driver or the device disappears, the queue state is invalid and
* ops are not usable anymore.
@@ -530,7 +533,7 @@ struct uacce_device *uacce_alloc(struct device *parent,
mutex_init(&uacce->mutex);
device_initialize(&uacce->dev);
uacce->dev.devt = MKDEV(MAJOR(uacce_devt), uacce->dev_id);
- uacce->dev.class = uacce_class;
+ uacce->dev.class = &uacce_class;
uacce->dev.groups = uacce_dev_groups;
uacce->dev.parent = uacce->parent;
uacce->dev.release = uacce_release;
@@ -623,13 +626,13 @@ static int __init uacce_init(void)
{
int ret;

- uacce_class = class_create(UACCE_NAME);
- if (IS_ERR(uacce_class))
- return PTR_ERR(uacce_class);
+ ret = class_register(&uacce_class);
+ if (ret)
+ return ret;

ret = alloc_chrdev_region(&uacce_devt, 0, MINORMASK, UACCE_NAME);
if (ret)
- class_destroy(uacce_class);
+ class_unregister(&uacce_class);

return ret;
}
@@ -637,7 +640,7 @@ static int __init uacce_init(void)
static __exit void uacce_exit(void)
{
unregister_chrdev_region(uacce_devt, MINORMASK);
- class_destroy(uacce_class);
+ class_unregister(&uacce_class);
}

subsys_initcall(uacce_init);
--
2.42.0

2023-10-26 02:22:59

by zhangfei

Subject: Re: [PATCH] uacce: make uacce_class constant

On Tue, 24 Oct 2023 at 19:50, Greg Kroah-Hartman
<[email protected]> wrote:
>
> Now that the driver core allows for struct class to be in read-only
> memory, we should make all 'class' structures declared at build time
> placing them into read-only memory, instead of having to be dynamically
> allocated at runtime.
>
> Cc: Zhangfei Gao <[email protected]>
> Cc: Zhou Wang <[email protected]>
> Cc: Arnd Bergmann <[email protected]>
> Cc: [email protected]
> Signed-off-by: Greg Kroah-Hartman <[email protected]>

Thanks, Greg

Tested-by: Zhangfei Gao <[email protected]>

2023-10-27 06:55:08

by Greg Kroah-Hartman

Subject: Re: [PATCH] uacce: make uacce_class constant

On Thu, Oct 26, 2023 at 10:21:52AM +0800, Zhangfei Gao wrote:
> On Tue, 24 Oct 2023 at 19:50, Greg Kroah-Hartman
> <[email protected]> wrote:
> >
> > Now that the driver core allows for struct class to be in read-only
> > memory, we should make all 'class' structures declared at build time
> > placing them into read-only memory, instead of having to be dynamically
> > allocated at runtime.
> >
> > Cc: Zhangfei Gao <[email protected]>
> > Cc: Zhou Wang <[email protected]>
> > Cc: Arnd Bergmann <[email protected]>
> > Cc: [email protected]
> > Signed-off-by: Greg Kroah-Hartman <[email protected]>
>
> Thanks, Greg
>
> Tested-by: Zhangfei Gao <[email protected]>

Wonderful, thanks for testing!