Re: [PATCH] accel/habanalabs: make hl_class constant

[Oded Gabbay]

On Fri, Oct 6, 2023 at 4:57 PM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> 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.
>
> This requires some passing of const struct class * around in the common
> habanalabs code as well as converting the structure itself.

Hi Greg,
Thanks for the patch but if you look at our tip of habanalabs-next
branch (to be merged in 6.7), you will see the hl_class related code
no longer exists, as we moved completely to the new accel char device
class.
So, I'm dropping this patch.
Oded

>
> Cc: Dafna Hirschfeld <dhirschfeld@xxxxxxxxx>
> Cc: Dani Liberman <dliberman@xxxxxxxxx>
> Cc: Koby Elbaz <kelbaz@xxxxxxxxx>
> Cc: Oded Gabbay <ogabbay@xxxxxxxxxx>
> Cc: Ofir Bitton <obitton@xxxxxxxxx>
> Cc: Ohad Sharabi <osharabi@xxxxxxxxx>
> Cc: Stanislaw Gruszka <stanislaw.gruszka@xxxxxxxxxxxxxxx>
> Cc: Tal Cohen <talcohen@xxxxxxxxx>
> Cc: Tomer Tayar <ttayar@xxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---
>  drivers/accel/habanalabs/common/device.c        |  2 +-
>  drivers/accel/habanalabs/common/habanalabs.h    |  2 +-
>  .../accel/habanalabs/common/habanalabs_drv.c    | 17 ++++++++++-------
>  3 files changed, 12 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/accel/habanalabs/common/device.c b/drivers/accel/habanalabs/common/device.c
> index b97339d1f7c6..4c28d8cfbb68 100644
> --- a/drivers/accel/habanalabs/common/device.c
> +++ b/drivers/accel/habanalabs/common/device.c
> @@ -652,7 +652,7 @@ static void device_release_func(struct device *dev)
>   *
>   * Initialize a cdev and a Linux device for habanalabs's device.
>   */
> -static int device_init_cdev(struct hl_device *hdev, struct class *class,
> +static int device_init_cdev(struct hl_device *hdev, const struct class *class,
>                                 int minor, const struct file_operations *fops,
>                                 char *name, struct cdev *cdev,
>                                 struct device **dev)
> diff --git a/drivers/accel/habanalabs/common/habanalabs.h b/drivers/accel/habanalabs/common/habanalabs.h
> index 2f027d5a8206..f1c78555e611 100644
> --- a/drivers/accel/habanalabs/common/habanalabs.h
> +++ b/drivers/accel/habanalabs/common/habanalabs.h
> @@ -3308,7 +3308,7 @@ struct hl_device {
>         u64                             pcie_bar_phys[HL_PCI_NUM_BARS];
>         void __iomem                    *pcie_bar[HL_PCI_NUM_BARS];
>         void __iomem                    *rmmio;
> -       struct class                    *hclass;
> +       const struct class              *hclass;
>         struct cdev                     cdev;
>         struct cdev                     cdev_ctrl;
>         struct device                   *dev;
> diff --git a/drivers/accel/habanalabs/common/habanalabs_drv.c b/drivers/accel/habanalabs/common/habanalabs_drv.c
> index 7263e84c1a4d..4f1fdff3843d 100644
> --- a/drivers/accel/habanalabs/common/habanalabs_drv.c
> +++ b/drivers/accel/habanalabs/common/habanalabs_drv.c
> @@ -27,7 +27,11 @@ MODULE_DESCRIPTION(HL_DRIVER_DESC);
>  MODULE_LICENSE("GPL v2");
>
>  static int hl_major;
> -static struct class *hl_class;
> +
> +static const struct class hl_class = {
> +       .name = HL_NAME,
> +};
> +
>  static DEFINE_IDR(hl_devs_idr);
>  static DEFINE_MUTEX(hl_devs_idr_lock);
>
> @@ -317,7 +321,7 @@ static void copy_kernel_module_params_to_device(struct hl_device *hdev)
>         hdev->asic_prop.fw_security_enabled = is_asic_secured(hdev->asic_type);
>
>         hdev->major = hl_major;
> -       hdev->hclass = hl_class;
> +       hdev->hclass = &hl_class;
>         hdev->memory_scrub = memory_scrub;
>         hdev->reset_on_lockup = reset_on_lockup;
>         hdev->boot_error_status_mask = boot_error_status_mask;
> @@ -691,10 +695,9 @@ static int __init hl_init(void)
>
>         hl_major = MAJOR(dev);
>
> -       hl_class = class_create(HL_NAME);
> -       if (IS_ERR(hl_class)) {
> +       rc = class_register(&hl_class);
> +       if (rc) {
>                 pr_err("failed to allocate class\n");
> -               rc = PTR_ERR(hl_class);
>                 goto remove_major;
>         }
>
> @@ -712,7 +715,7 @@ static int __init hl_init(void)
>
>  remove_debugfs:
>         hl_debugfs_fini();
> -       class_destroy(hl_class);
> +       class_unregister(&hl_class);
>  remove_major:
>         unregister_chrdev_region(MKDEV(hl_major, 0), HL_MAX_MINORS);
>         return rc;
> @@ -732,7 +735,7 @@ static void __exit hl_exit(void)
>          */
>         hl_debugfs_fini();
>
> -       class_destroy(hl_class);
> +       class_unregister(&hl_class);
>         unregister_chrdev_region(MKDEV(hl_major, 0), HL_MAX_MINORS);
>
>         idr_destroy(&hl_devs_idr);
> --
> 2.42.0
>