Re: [PATCH v2 1/3] mm: convert memory block states (MEM_*) macros to enum

[Lorenzo Stoakes <lorenzo.stoakes@oracle.com>]

On Wed, Oct 29, 2025 at 07:56:28PM +0000, Israel Batista wrote:
> Converting the MEM_* constants from macros to an enum ensures that their
> values will be correctly emitted in the debug symbols, making it easier
> to trace the meaning of each value when debugging with tools such as
> drgn, without the need to hard-code the values.
>
> Since the values are mutually exclusive and they are not exposed directly to
> userspace, I also dropped the misleading pattern (1<<X) that made it look like
> they were combinable flags.
>
> Signed-off-by: Israel Batista <linux@israelbatista.dev.br>

LGTM, so:

Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

> ---
>  include/linux/memory.h | 22 ++++++++++++----------
>  1 file changed, 12 insertions(+), 10 deletions(-)
>
> diff --git a/include/linux/memory.h b/include/linux/memory.h
> index 0c214256216f..f4e358477c6a 100644
> --- a/include/linux/memory.h
> +++ b/include/linux/memory.h
> @@ -64,6 +64,18 @@ struct memory_group {
>  	};
>  };
>
> +enum memory_block_state {
> +	/* These states are exposed to userspace as text strings in sysfs */
> +	MEM_ONLINE,		/* exposed to userspace */
> +	MEM_GOING_OFFLINE,	/* exposed to userspace */
> +	MEM_OFFLINE,		/* exposed to userspace */
> +	MEM_GOING_ONLINE,
> +	MEM_CANCEL_ONLINE,
> +	MEM_CANCEL_OFFLINE,
> +	MEM_PREPARE_ONLINE,
> +	MEM_FINISH_OFFLINE,
> +};
> +
>  struct memory_block {
>  	unsigned long start_section_nr;
>  	unsigned long state;		/* serialized by the dev->lock */
> @@ -89,16 +101,6 @@ int arch_get_memory_phys_device(unsigned long start_pfn);
>  unsigned long memory_block_size_bytes(void);
>  int set_memory_block_size_order(unsigned int order);
>
> -/* These states are exposed to userspace as text strings in sysfs */
> -#define	MEM_ONLINE		(1<<0) /* exposed to userspace */
> -#define	MEM_GOING_OFFLINE	(1<<1) /* exposed to userspace */
> -#define	MEM_OFFLINE		(1<<2) /* exposed to userspace */
> -#define	MEM_GOING_ONLINE	(1<<3)
> -#define	MEM_CANCEL_ONLINE	(1<<4)
> -#define	MEM_CANCEL_OFFLINE	(1<<5)
> -#define	MEM_PREPARE_ONLINE	(1<<6)
> -#define	MEM_FINISH_OFFLINE	(1<<7)
> -
>  struct memory_notify {
>  	/*
>  	 * The altmap_start_pfn and altmap_nr_pages fields are designated for
> --
> 2.51.0
>