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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: Christophe LEROY <christophe.leroy@c-s.fr>,
	npiggin@gmail.com, benh@kernel.crashing.org, paulus@samba.org,
	mpe@ellerman.id.au, akpm@linux-foundation.org
Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH V3 2/5] mm: update ptep_modify_prot_commit to take old pte value as arg
Date: Wed, 5 Dec 2018 09:36:41 +0530	[thread overview]
Message-ID: <48f13462-1695-a759-9df8-1ef60fd88196@linux.ibm.com> (raw)
In-Reply-To: <f446afd3-a77d-cc5a-1ac8-3992090bcd7d@c-s.fr>

On 12/5/18 9:32 AM, Christophe LEROY wrote:
> 
> 
> Le 05/12/2018 à 04:09, Aneesh Kumar K.V a écrit :
>> Architectures like ppc64 requires to do a conditional tlb flush based 
>> on the old
>> and new value of pte. Enable that by passing old pte value as the arg.
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> ---
>>   arch/s390/include/asm/pgtable.h | 3 ++-
>>   arch/s390/mm/pgtable.c          | 2 +-
>>   arch/x86/include/asm/paravirt.h | 2 +-
>>   fs/proc/task_mmu.c              | 8 +++++---
>>   include/asm-generic/pgtable.h   | 2 +-
>>   mm/memory.c                     | 8 ++++----
>>   mm/mprotect.c                   | 6 +++---
>>   7 files changed, 17 insertions(+), 14 deletions(-)
>>
>> diff --git a/arch/s390/include/asm/pgtable.h 
>> b/arch/s390/include/asm/pgtable.h
>> index 5d730199e37b..76dc344edb8c 100644
>> --- a/arch/s390/include/asm/pgtable.h
>> +++ b/arch/s390/include/asm/pgtable.h
>> @@ -1070,7 +1070,8 @@ static inline pte_t ptep_get_and_clear(struct 
>> mm_struct *mm,
>>   #define __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
>>   pte_t ptep_modify_prot_start(struct vm_area_struct *, unsigned long, 
>> pte_t *);
>> -void ptep_modify_prot_commit(struct vm_area_struct *, unsigned long, 
>> pte_t *, pte_t);
>> +void ptep_modify_prot_commit(struct vm_area_struct *, unsigned long,
>> +                 pte_t *, pte_t, pte_t);
>>   #define __HAVE_ARCH_PTEP_CLEAR_FLUSH
>>   static inline pte_t ptep_clear_flush(struct vm_area_struct *vma,
>> diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
>> index 29c0a21cd34a..b283b92722cc 100644
>> --- a/arch/s390/mm/pgtable.c
>> +++ b/arch/s390/mm/pgtable.c
>> @@ -322,7 +322,7 @@ pte_t ptep_modify_prot_start(struct vm_area_struct 
>> *vma, unsigned long addr,
>>   EXPORT_SYMBOL(ptep_modify_prot_start);
>>   void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned 
>> long addr,
>> -                 pte_t *ptep, pte_t pte)
>> +                 pte_t *ptep, pte_t old_pte, pte_t pte)
>>   {
>>       pgste_t pgste;
>>       struct mm_struct *mm = vma->vm_mm;
>> diff --git a/arch/x86/include/asm/paravirt.h 
>> b/arch/x86/include/asm/paravirt.h
>> index 1154f154025d..0d75a4f60500 100644
>> --- a/arch/x86/include/asm/paravirt.h
>> +++ b/arch/x86/include/asm/paravirt.h
>> @@ -429,7 +429,7 @@ static inline pte_t ptep_modify_prot_start(struct 
>> vm_area_struct *vma, unsigned
>>   }
>>   static inline void ptep_modify_prot_commit(struct vm_area_struct 
>> *vma, unsigned long addr,
>> -                       pte_t *ptep, pte_t pte)
>> +                       pte_t *ptep, pte_t old_pte, pte_t pte)
>>   {
>>       struct mm_struct *mm = vma->vm_mm;
>> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
>> index 9952d7185170..8d62891d38a8 100644
>> --- a/fs/proc/task_mmu.c
>> +++ b/fs/proc/task_mmu.c
>> @@ -940,10 +940,12 @@ static inline void clear_soft_dirty(struct 
>> vm_area_struct *vma,
>>       pte_t ptent = *pte;
>>       if (pte_present(ptent)) {
>> -        ptent = ptep_modify_prot_start(vma, addr, pte);
>> -        ptent = pte_wrprotect(ptent);
>> +        pte_t old_pte;
>> +
>> +        old_pte = ptep_modify_prot_start(vma, addr, pte);
>> +        ptent = pte_wrprotect(old_pte);
> 
> This change doesn't seem to fit with the commit description. Why write 
> protecting in addition to clearing dirty ?
> 
>

The hunk above use a new variable old_pte. There is no functional change 
in that hunk.

-aneesh


  reply	other threads:[~2018-12-05  4:08 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-05  3:09 [PATCH V3 0/5] NestMMU pte upgrade workaround for mprotect Aneesh Kumar K.V
2018-12-05  3:09 ` [PATCH V3 1/5] mm: Update ptep_modify_prot_start/commit to take vm_area_struct as arg Aneesh Kumar K.V
2018-12-06 21:58   ` kbuild test robot
2018-12-08 15:32     ` Aneesh Kumar K.V
2018-12-05  3:09 ` [PATCH V3 2/5] mm: update ptep_modify_prot_commit to take old pte value " Aneesh Kumar K.V
2018-12-05  4:02   ` Christophe LEROY
2018-12-05  4:06     ` Aneesh Kumar K.V [this message]
2018-12-05  4:42       ` Christophe LEROY
2018-12-05  3:09 ` [PATCH V3 3/5] arch/powerpc/mm: Nest MMU workaround for mprotect RW upgrade Aneesh Kumar K.V
2018-12-18 17:21   ` Christoph Hellwig
2018-12-05  3:09 ` [PATCH V3 4/5] mm/hugetlb: Add prot_modify_start/commit sequence for hugetlb update Aneesh Kumar K.V
2018-12-05  3:09 ` [PATCH V3 5/5] arch/powerpc/mm/hugetlb: NestMMU workaround for hugetlb mprotect RW upgrade Aneesh Kumar K.V
2018-12-05  3:57   ` Christophe LEROY
2018-12-05  4:09     ` Aneesh Kumar K.V
2018-12-05  4:11   ` [PATCH V3 updated] " Aneesh Kumar K.V
2018-12-08  1:04     ` kbuild test robot

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