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

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Date:	Thu, 13 May 2010 23:44:40 -0700
From:	Yinghai <yinghai.lu@...cle.com>
To:	Benjamin Herrenschmidt <benh@...nel.crashing.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 05/13/2010 07:32 PM, Benjamin Herrenschmidt wrote:
> 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.

make every lmb_reserve() call lmb_free at first?

> 
> 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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