linux-kernel - Re: [PATCH v15 04/16] powerpc, kexec_file: factor out memblock-based arch_kexec_walk

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Date:   Sun, 30 Sep 2018 18:08:34 +0800
From:   Dave Young <dyoung@...hat.com>
To:     AKASHI Takahiro <takahiro.akashi@...aro.org>
Cc:     catalin.marinas@....com, will.deacon@....com, dhowells@...hat.com,
        vgoyal@...hat.com, herbert@...dor.apana.org.au,
        davem@...emloft.net, bhe@...hat.com, arnd@...db.de,
        schwidefsky@...ibm.com, heiko.carstens@...ibm.com,
        ard.biesheuvel@...aro.org, bhsharma@...hat.com,
        kexec@...ts.infradead.org, linux-kernel@...r.kernel.org,
        prudo@...ux.ibm.com, james.morse@....com,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v15 04/16] powerpc, kexec_file: factor out memblock-based
 arch_kexec_walk_mem()

Hi AKASHI,

On 09/28/18 at 03:48pm, AKASHI Takahiro wrote:
> Memblock list is another source for usable system memory layout.
> So move powerpc's arch_kexec_walk_mem() to common code so that other
> memblock-based architectures, particularly arm64, can also utilise it.
> A moved function is now renamed to kexec_walk_memblock() and integrated
> into kexec_locate_mem_hole(), which will now be usable for all
> architectures with no need for overriding arch_kexec_walk_mem().
> 
> With this change, arch_kexec_walk_mem() need no longer be a weak function,
> and was now renamed to kexec_walk_resources().
> 
> Since powerpc doesn't support kdump in its kexec_file_load(), the current
> kexec_walk_memblock() won't work for kdump either in this form, this will
> be fixed in the next patch.
> 
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@...aro.org>
> Cc: "Eric W. Biederman" <ebiederm@...ssion.com>
> Acked-by: Dave Young <dyoung@...hat.com>
> Cc: Vivek Goyal <vgoyal@...hat.com>
> Cc: Baoquan He <bhe@...hat.com>
> Acked-by: James Morse <james.morse@....com>

[snip]

> +
>  /**
>   * arch_kexec_walk_mem - call func(data) on free memory regions

The function name should be updated as well.

>   * @kbuf:	Context info for the search. Also passed to @func.
> @@ -510,8 +560,8 @@ static int locate_mem_hole_callback(struct resource *res, void *arg)
>   * and that value will be returned. If all free regions are visited without
>   * func returning non-zero, then zero will be returned.
>   */
> -int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
> -			       int (*func)(struct resource *, void *))
> +static int kexec_walk_resources(struct kexec_buf *kbuf,
> +				int (*func)(struct resource *, void *))
>  {
>  	if (kbuf->image->type == KEXEC_TYPE_CRASH)
>  		return walk_iomem_res_desc(crashk_res.desc,
> @@ -538,7 +588,11 @@ int kexec_locate_mem_hole(struct kexec_buf *kbuf)
>  	if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
>  		return 0;
>  
> -	ret = arch_kexec_walk_mem(kbuf, locate_mem_hole_callback);
> +	if (IS_ENABLED(CONFIG_HAVE_MEMBLOCK) &&
> +			!IS_ENABLED(CONFIG_ARCH_DISCARD_MEMBLOCK))
> +		ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);
> +	else
> +		ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
>  
>  	return ret == 1 ? 0 : -EADDRNOTAVAIL;
>  }
> -- 
> 2.19.0
> 

Thanks
Dave