linux-kernel - Re: [PATCH 15/35] x86, lmb: Add lmb_reserve_area_overlap

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Date:	Fri, 14 May 2010 12:32:17 +1000
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	Yinghai Lu <yinghai@...nel.org>
Cc:	Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	David Miller <davem@...emloft.net>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Johannes Weiner <hannes@...xchg.org>,
	linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org
Subject: Re: [PATCH 15/35] x86, lmb: Add lmb_reserve_area_overlap_ok()

On Thu, 2010-05-13 at 17:19 -0700, Yinghai Lu wrote:
> Some areas from firmware could be reserved several times from different callers.
> 
> If these area are overlapped, We may have overlapped entries in lmb.reserved.
> 
> Try to free the area at first, before rerserve them again.

I have already told you to make this a property of lmb_reserve() instead
of adding that function with a terrible name.

Cheers,
Ben.

> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
> ---
>  arch/x86/include/asm/lmb.h |    1 +
>  arch/x86/mm/lmb.c          |   18 ++++++++++++++++++
>  2 files changed, 19 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/include/asm/lmb.h b/arch/x86/include/asm/lmb.h
> index dd42ac1..9329e09 100644
> --- a/arch/x86/include/asm/lmb.h
> +++ b/arch/x86/include/asm/lmb.h
> @@ -7,6 +7,7 @@ u64 lmb_find_area_size(u64 start, u64 *sizep, u64 align);
>  void lmb_to_bootmem(u64 start, u64 end);
>  
>  void lmb_reserve_area(u64 start, u64 end, char *name);
> +void lmb_reserve_area_overlap_ok(u64 start, u64 end, char *name);
>  void lmb_free_area(u64 start, u64 end);
>  void lmb_add_memory(u64 start, u64 end);
>  struct range;
> diff --git a/arch/x86/mm/lmb.c b/arch/x86/mm/lmb.c
> index 19a5f49..1100c18 100644
> --- a/arch/x86/mm/lmb.c
> +++ b/arch/x86/mm/lmb.c
> @@ -309,6 +309,24 @@ void __init lmb_reserve_area(u64 start, u64 end, char *name)
>  	lmb_add_region(&lmb.reserved, start, end - start);
>  }
>  
> +/*
> + * Could be used to avoid having overlap entries in lmb.reserved.region.
> + *  Don't need to use it with area that is from lmb_find_area()
> + *  Only use it for the area that fw hidden area.
> + */
> +void __init lmb_reserve_area_overlap_ok(u64 start, u64 end, char *name)
> +{
> +	if (start == end)
> +		return;
> +
> +	if (WARN_ONCE(start > end, "lmb_reserve_area_overlap_ok: wrong range [%#llx, %#llx]\n", start, end))
> +		return;
> +
> +	/* Free that region at first */
> +	lmb_free(start, end - start);
> +	lmb_add_region(&lmb.reserved, start, end - start);
> +}
> +
>  void __init lmb_free_area(u64 start, u64 end)
>  {
>  	if (start == end)


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