linux-kernel - Re: [PATCH v2 2/9] kexec_file: Generalize kexec_add

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Date:	Mon, 20 Jun 2016 10:26:05 +0800
From:	Dave Young <dyoung@...hat.com>
To:	Thiago Jung Bauermann <bauerman@...ux.vnet.ibm.com>
Cc:	kexec@...ts.infradead.org, linuxppc-dev@...ts.ozlabs.org,
	linux-kernel@...r.kernel.org,
	Eric Biederman <ebiederm@...ssion.com>
Subject: Re: [PATCH v2 2/9] kexec_file: Generalize kexec_add_buffer.

On 06/17/16 at 05:51pm, Thiago Jung Bauermann wrote:
> Am Freitag, 17 Juni 2016, 15:35:23 schrieb Dave Young:
> > On 06/16/16 at 05:39pm, Thiago Jung Bauermann wrote:
> > > Am Donnerstag, 16 Juni 2016, 09:58:53 schrieb Dave Young:
> > > > On 06/15/16 at 01:21pm, Thiago Jung Bauermann wrote:
> > > > > +int __weak arch_kexec_walk_mem(unsigned int image_type, bool
> > > > > top_down,
> > > > > +			       void *data, int (*func)(u64, u64, void *))
> > > > > +{
> > > > 
> > > > top_down is also not used?
> > > 
> > > It's unused in the default implementation, but the powerpc implementation
> > > in patch 8 uses it:
> > Well, arch_kexec_walk_mem use kbuf as "data", you can even drop
> > "image_type" since kbuf has all you want kbuf->image->type, and
> > kbuf->top_down
> > 
> > int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
> > 			       int (*func)(u64, u64, void *))
> 
> Sounds good to me, but I had to move struct kexec_buf from
> kernel/kexec_internal.h to include/linux/kexec.h.
> 
> Here's the updated patch. What do you think?
> 
> []'s
> Thiago Jung Bauermann
> IBM Linux Technology Center
> 
> 
>     kexec_file: Generalize kexec_add_buffer.
>     
>     Allow architectures to specify different memory walking functions for
>     kexec_add_buffer. Intel uses iomem to track reserved memory ranges,
>     but PowerPC uses the memblock subsystem.
>     
>     Signed-off-by: Thiago Jung Bauermann <bauerman@...ux.vnet.ibm.com>
>     Cc: Eric Biederman <ebiederm@...ssion.com>
>     Cc: Dave Young <dyoung@...hat.com>
>     Cc: kexec@...ts.infradead.org
>     Cc: linux-kernel@...r.kernel.org
> 
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index e8acb2b43dd9..d8df01107ae2 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -201,6 +201,20 @@ struct kimage {
>  #endif
>  };
>  
> +/*
> + * Keeps track of buffer parameters as provided by caller for requesting
> + * memory placement of buffer.
> + */
> +struct kexec_buf {
> +	struct kimage *image;
> +	unsigned long mem;
> +	unsigned long memsz;
> +	unsigned long buf_align;
> +	unsigned long buf_min;
> +	unsigned long buf_max;
> +	bool top_down;		/* allocate from top of memory hole */
> +};
> +

kexec_buf should go within #ifdef for kexec file like struct purgatory_info

Other than that it looks good.

Thanks
Dave