linux-kernel - Re: [v1 3/6] memblock: add parameter to memblock_setclr_flag for selecting memblock

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Date:   Sat, 29 Jul 2023 09:42:33 +0300
From:   Mike Rapoport <rppt@...nel.org>
To:     Usama Arif <usama.arif@...edance.com>
Cc:     linux-mm@...ck.org, muchun.song@...ux.dev, mike.kravetz@...cle.com,
        linux-kernel@...r.kernel.org, fam.zheng@...edance.com,
        liangma@...ngbit.com, simon.evans@...edance.com,
        punit.agrawal@...edance.com
Subject: Re: [v1 3/6] memblock: add parameter to memblock_setclr_flag for
 selecting memblock_type

On Thu, Jul 27, 2023 at 09:46:21PM +0100, Usama Arif wrote:
> This is in preparation for setting flags (for e.g. to not initialize
> struct pages) on reserved memory region.
> 
> Signed-off-by: Usama Arif <usama.arif@...edance.com>
> ---
>  mm/memblock.c | 19 ++++++++++++-------
>  1 file changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/mm/memblock.c b/mm/memblock.c
> index f9e61e565a53..4fd431d16ef2 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -897,11 +897,16 @@ int __init_memblock memblock_physmem_add(phys_addr_t base, phys_addr_t size)
>   * Return: 0 on success, -errno on failure.
>   */
>  static int __init_memblock memblock_setclr_flag(phys_addr_t base,
> -				phys_addr_t size, int set, int flag)
> +				phys_addr_t size, int set, int flag, bool reserved)
>  {

Please pass struct memblock_type * as the first parameter and set the flags
unconditionally.
The boolean parameters make code less readable. Besides if we'll add more
flags for reserved regions it'll become really hairy.

> -	struct memblock_type *type = &memblock.memory;
> +	struct memblock_type *type;
>  	int i, ret, start_rgn, end_rgn;
>  
> +	if (reserved)
> +		type = &memblock.reserved;
> +	else
> +		type = &memblock.memory;
> +
>  	ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
>  	if (ret)
>  		return ret;
> @@ -928,7 +933,7 @@ static int __init_memblock memblock_setclr_flag(phys_addr_t base,
>   */
>  int __init_memblock memblock_mark_hotplug(phys_addr_t base, phys_addr_t size)
>  {
> -	return memblock_setclr_flag(base, size, 1, MEMBLOCK_HOTPLUG);
> +	return memblock_setclr_flag(base, size, 1, MEMBLOCK_HOTPLUG, 0);
>  }
>  
>  /**
> @@ -940,7 +945,7 @@ int __init_memblock memblock_mark_hotplug(phys_addr_t base, phys_addr_t size)
>   */
>  int __init_memblock memblock_clear_hotplug(phys_addr_t base, phys_addr_t size)
>  {
> -	return memblock_setclr_flag(base, size, 0, MEMBLOCK_HOTPLUG);
> +	return memblock_setclr_flag(base, size, 0, MEMBLOCK_HOTPLUG, 0);
>  }
>  
>  /**
> @@ -957,7 +962,7 @@ int __init_memblock memblock_mark_mirror(phys_addr_t base, phys_addr_t size)
>  
>  	system_has_some_mirror = true;
>  
> -	return memblock_setclr_flag(base, size, 1, MEMBLOCK_MIRROR);
> +	return memblock_setclr_flag(base, size, 1, MEMBLOCK_MIRROR, 0);
>  }
>  
>  /**
> @@ -977,7 +982,7 @@ int __init_memblock memblock_mark_mirror(phys_addr_t base, phys_addr_t size)
>   */
>  int __init_memblock memblock_mark_nomap(phys_addr_t base, phys_addr_t size)
>  {
> -	return memblock_setclr_flag(base, size, 1, MEMBLOCK_NOMAP);
> +	return memblock_setclr_flag(base, size, 1, MEMBLOCK_NOMAP, 0);
>  }
>  
>  /**
> @@ -989,7 +994,7 @@ int __init_memblock memblock_mark_nomap(phys_addr_t base, phys_addr_t size)
>   */
>  int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size)
>  {
> -	return memblock_setclr_flag(base, size, 0, MEMBLOCK_NOMAP);
> +	return memblock_setclr_flag(base, size, 0, MEMBLOCK_NOMAP, 0);
>  }
>  
>  static bool should_skip_region(struct memblock_type *type,
> -- 
> 2.25.1
> 

-- 
Sincerely yours,
Mike.