linux-kernel - Re: [PATCH 5/6] kexec: add helper __crash_shrink

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Message-ID: <ZHb8Ms1T32K+Iyo2@MiWiFi-R3L-srv>
Date:   Wed, 31 May 2023 15:50:25 +0800
From:   Baoquan He <bhe@...hat.com>
To:     Zhen Lei <thunder.leizhen@...wei.com>
Cc:     Eric Biederman <ebiederm@...ssion.com>, kexec@...ts.infradead.org,
        linux-kernel@...r.kernel.org,
        Michael Holzheu <holzheu@...ux.vnet.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 5/6] kexec: add helper __crash_shrink_memory()

On 05/27/23 at 08:34pm, Zhen Lei wrote:
> No functional change, in preparation for the next patch so that it is
> easier to review.
> 
> Signed-off-by: Zhen Lei <thunder.leizhen@...wei.com>
> ---
>  kernel/kexec_core.c | 50 +++++++++++++++++++++++++--------------------
>  1 file changed, 28 insertions(+), 22 deletions(-)
> 
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index 69fe92141b0b62d..e82bc6d6634136a 100644
> --- a/kernel/kexec_core.c
> +++ b/kernel/kexec_core.c
> @@ -1105,11 +1105,37 @@ ssize_t crash_get_memory_size(void)
>  	return size;
>  }
>  
> +int __crash_shrink_memory(struct resource *old_res, unsigned long new_size)

Other than the missing static, looks good,

Acked-by: Baoquan He <bhe@...hat.com>

> +{
> +	struct resource *ram_res;
> +
> +	ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL);
> +	if (!ram_res)
> +		return -ENOMEM;
> +
> +	ram_res->start = old_res->start + new_size;
> +	ram_res->end   = old_res->end;
> +	ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM;
> +	ram_res->name  = "System RAM";
> +
> +	if (!new_size) {
> +		release_resource(old_res);
> +		old_res->start = 0;
> +		old_res->end   = 0;
> +	} else {
> +		crashk_res.end = ram_res->start - 1;
> +	}
> +
> +	crash_free_reserved_phys_range(ram_res->start, ram_res->end);
> +	insert_resource(&iomem_resource, ram_res);
> +
> +	return 0;
> +}
> +
>  int crash_shrink_memory(unsigned long new_size)
>  {
>  	int ret = 0;
>  	unsigned long old_size;
> -	struct resource *ram_res;
>  
>  	if (!kexec_trylock())
>  		return -EBUSY;
> @@ -1125,27 +1151,7 @@ int crash_shrink_memory(unsigned long new_size)
>  		goto unlock;
>  	}
>  
> -	ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL);
> -	if (!ram_res) {
> -		ret = -ENOMEM;
> -		goto unlock;
> -	}
> -
> -	ram_res->start = crashk_res.start + new_size;
> -	ram_res->end = crashk_res.end;
> -	ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM;
> -	ram_res->name = "System RAM";
> -
> -	if (!new_size) {
> -		release_resource(&crashk_res);
> -		crashk_res.start = 0;
> -		crashk_res.end = 0;
> -	} else {
> -		crashk_res.end = ram_res->start - 1;
> -	}
> -
> -	crash_free_reserved_phys_range(ram_res->start, ram_res->end);
> -	insert_resource(&iomem_resource, ram_res);
> +	ret = __crash_shrink_memory(&crashk_res, new_size);
>  
>  unlock:
>  	kexec_unlock();
> -- 
> 2.25.1
>