On 2024/3/6 4:21, 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 bch_chardev_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 <[email protected]>
> Suggested-by: Greg Kroah-Hartman <[email protected]>
> Signed-off-by: Ricardo B. Marliere <[email protected]>
> ---
> fs/bcachefs/chardev.c | 23 ++++++++++++-----------
> 1 file changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/fs/bcachefs/chardev.c b/fs/bcachefs/chardev.c
> index 226b39c17667..af587453fd3d 100644
> --- a/fs/bcachefs/chardev.c
> +++ b/fs/bcachefs/chardev.c
> @@ -940,7 +940,9 @@ static const struct file_operations bch_chardev_fops = {
> };
>
> static int bch_chardev_major;
> -static struct class *bch_chardev_class;
> +static const struct class bch_chardev_class = {
> + .name = "bcachefs",
> +};
> static struct device *bch_chardev;
>
> void bch2_fs_chardev_exit(struct bch_fs *c)
> @@ -957,7 +959,7 @@ int bch2_fs_chardev_init(struct bch_fs *c)
> if (c->minor < 0)
> return c->minor;
>
> - c->chardev = device_create(bch_chardev_class, NULL,
> + c->chardev = device_create(&bch_chardev_class, NULL,
> MKDEV(bch_chardev_major, c->minor), c,
> "bcachefs%u-ctl", c->minor);
> if (IS_ERR(c->chardev))
> @@ -968,26 +970,25 @@ int bch2_fs_chardev_init(struct bch_fs *c)
>
> void bch2_chardev_exit(void)
> {
> - if (!IS_ERR_OR_NULL(bch_chardev_class))
> - device_destroy(bch_chardev_class,
> - MKDEV(bch_chardev_major, U8_MAX));
> - if (!IS_ERR_OR_NULL(bch_chardev_class))
> - class_destroy(bch_chardev_class);
> + device_destroy(&bch_chardev_class, MKDEV(bch_chardev_major, U8_MAX));
> + class_unregister(&bch_chardev_class);
> if (bch_chardev_major > 0)
> unregister_chrdev(bch_chardev_major, "bcachefs");
> }
>
> int __init bch2_chardev_init(void)
> {
> + int ret;
> +
> bch_chardev_major = register_chrdev(0, "bcachefs-ctl", &bch_chardev_fops);
> if (bch_chardev_major < 0)
> return bch_chardev_major;
>
> - bch_chardev_class = class_create("bcachefs");
> - if (IS_ERR(bch_chardev_class))
> - return PTR_ERR(bch_chardev_class);
> + ret = class_register(&bch_chardev_class);
> + if (ret)
Here, I think you should call class_unregister to relase resource which
allocated before. And the same thing shoud be done in other exception exit.
> + return ret;
>
> - bch_chardev = device_create(bch_chardev_class, NULL,
> + bch_chardev = device_create(&bch_chardev_class, NULL,
> MKDEV(bch_chardev_major, U8_MAX),
> NULL, "bcachefs-ctl");
> if (IS_ERR(bch_chardev))
like here..
>
> ---
> base-commit: 90d35da658da8cff0d4ecbb5113f5fac9d00eb72
> change-id: 20240305-bcachefs-27a4bb8b9f4f
>
> Best regards,
On 6 Mar 09:23, Hongbo Li wrote:
> On 2024/3/6 4:21, 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 bch_chardev_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 <[email protected]>
> > Suggested-by: Greg Kroah-Hartman <[email protected]>
> > Signed-off-by: Ricardo B. Marliere <[email protected]>
> > ---
> > fs/bcachefs/chardev.c | 23 ++++++++++++-----------
> > 1 file changed, 12 insertions(+), 11 deletions(-)
> >
> > diff --git a/fs/bcachefs/chardev.c b/fs/bcachefs/chardev.c
> > index 226b39c17667..af587453fd3d 100644
> > --- a/fs/bcachefs/chardev.c
> > +++ b/fs/bcachefs/chardev.c
> > @@ -940,7 +940,9 @@ static const struct file_operations bch_chardev_fops = {
> > };
> >
> > static int bch_chardev_major;
> > -static struct class *bch_chardev_class;
> > +static const struct class bch_chardev_class = {
> > + .name = "bcachefs",
> > +};
> > static struct device *bch_chardev;
> >
> > void bch2_fs_chardev_exit(struct bch_fs *c)
> > @@ -957,7 +959,7 @@ int bch2_fs_chardev_init(struct bch_fs *c)
> > if (c->minor < 0)
> > return c->minor;
> >
> > - c->chardev = device_create(bch_chardev_class, NULL,
> > + c->chardev = device_create(&bch_chardev_class, NULL,
> > MKDEV(bch_chardev_major, c->minor), c,
> > "bcachefs%u-ctl", c->minor);
> > if (IS_ERR(c->chardev))
> > @@ -968,26 +970,25 @@ int bch2_fs_chardev_init(struct bch_fs *c)
> >
> > void bch2_chardev_exit(void)
> > {
> > - if (!IS_ERR_OR_NULL(bch_chardev_class))
> > - device_destroy(bch_chardev_class,
> > - MKDEV(bch_chardev_major, U8_MAX));
> > - if (!IS_ERR_OR_NULL(bch_chardev_class))
> > - class_destroy(bch_chardev_class);
> > + device_destroy(&bch_chardev_class, MKDEV(bch_chardev_major, U8_MAX));
> > + class_unregister(&bch_chardev_class);
> > if (bch_chardev_major > 0)
> > unregister_chrdev(bch_chardev_major, "bcachefs");
> > }
> >
> > int __init bch2_chardev_init(void)
> > {
> > + int ret;
> > +
> > bch_chardev_major = register_chrdev(0, "bcachefs-ctl", &bch_chardev_fops);
> > if (bch_chardev_major < 0)
> > return bch_chardev_major;
> >
> > - bch_chardev_class = class_create("bcachefs");
> > - if (IS_ERR(bch_chardev_class))
> > - return PTR_ERR(bch_chardev_class);
> > + ret = class_register(&bch_chardev_class);
> > + if (ret)
> Here, I think you should call class_unregister to relase resource which
> allocated before. And the same thing shoud be done in other exception exit.
Hi Hongbo,
Thank you for the feedback. Did you mean that bch_chardev_major should
be unregistered if the class_register() call fails? Because if it does,
there is no need to call class_unregister().
> > + return ret;
> >
> > - bch_chardev = device_create(bch_chardev_class, NULL,
> > + bch_chardev = device_create(&bch_chardev_class, NULL,
> > MKDEV(bch_chardev_major, U8_MAX),
> > NULL, "bcachefs-ctl");
> > if (IS_ERR(bch_chardev))
> like here..
Can you please elaborate?
Best regards,
- Ricardo.
> >
> > ---
> > base-commit: 90d35da658da8cff0d4ecbb5113f5fac9d00eb72
> > change-id: 20240305-bcachefs-27a4bb8b9f4f
> >
> > Best regards,