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

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Date:   Tue, 2 Oct 2018 15:20:23 +0900
From:   AKASHI Takahiro <takahiro.akashi@...aro.org>
To:     Dave Young <dyoung@...hat.com>
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()

On Sun, Sep 30, 2018 at 06:08:34PM +0800, Dave Young wrote:
> 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.

Ah, thank you.
-Takahiro Akashi

> >   * @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