2022-11-25 04:03:18

by Anshuman Khandual

[permalink] [raw]
Subject: [PATCH] s390/mm: Use pmd_pgtable_page() helper in __gmap_segment_gaddr()

In __gmap_segment_gaddr() pmd level page table page is being extracted from
the pmd pointer, similar to pmd_pgtable_page() implementation. This reduces
some redundancy by directly using pmd_pgtable_page() instead, though first
making it available.

Cc: Christian Borntraeger <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Anshuman Khandual <[email protected]>
---
This applies on v6.1-rc6 but after the following patch. Build tested for
s390 plaform (defconfig).

https://lore.kernel.org/all/[email protected]/

arch/s390/mm/gmap.c | 5 ++---
include/linux/mm.h | 2 +-
2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index 02d15c8dc92e..8947451ae021 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -336,12 +336,11 @@ static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
static unsigned long __gmap_segment_gaddr(unsigned long *entry)
{
struct page *page;
- unsigned long offset, mask;
+ unsigned long offset;

offset = (unsigned long) entry / sizeof(unsigned long);
offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
- mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
- page = virt_to_page((void *)((unsigned long) entry & mask));
+ page = pmd_pgtable_page((pmd_t *) entry);
return page->index + offset;
}

diff --git a/include/linux/mm.h b/include/linux/mm.h
index e9e387caffac..5ead9e997510 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2403,7 +2403,7 @@ static inline void pgtable_pte_page_dtor(struct page *page)

#if USE_SPLIT_PMD_PTLOCKS

-static struct page *pmd_pgtable_page(pmd_t *pmd)
+static inline struct page *pmd_pgtable_page(pmd_t *pmd)
{
unsigned long mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
return virt_to_page((void *)((unsigned long) pmd & mask));
--
2.25.1


2022-11-28 06:45:57

by Anshuman Khandual

[permalink] [raw]
Subject: Re: [PATCH] s390/mm: Use pmd_pgtable_page() helper in __gmap_segment_gaddr()



On 11/28/22 11:37, Alexander Gordeev wrote:
> On Fri, Nov 25, 2022 at 09:15:02AM +0530, Anshuman Khandual wrote:
>
> Hi Anshuman,
>
>> In __gmap_segment_gaddr() pmd level page table page is being extracted from
>> the pmd pointer, similar to pmd_pgtable_page() implementation. This reduces
>> some redundancy by directly using pmd_pgtable_page() instead, though first
>> making it available.
>
> [...]
>
>> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
>> index 02d15c8dc92e..8947451ae021 100644
>> --- a/arch/s390/mm/gmap.c
>> +++ b/arch/s390/mm/gmap.c
>> @@ -336,12 +336,11 @@ static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
>> static unsigned long __gmap_segment_gaddr(unsigned long *entry)
>> {
>> struct page *page;
>> - unsigned long offset, mask;
>> + unsigned long offset;
>>
>> offset = (unsigned long) entry / sizeof(unsigned long);
>> offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
>> - mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
>> - page = virt_to_page((void *)((unsigned long) entry & mask));
>> + page = pmd_pgtable_page((pmd_t *) entry);
>> return page->index + offset;
>> }
>
> Looks okay to me.
>
>> diff --git a/include/linux/mm.h b/include/linux/mm.h
>> index e9e387caffac..5ead9e997510 100644
>> --- a/include/linux/mm.h
>> +++ b/include/linux/mm.h
>> @@ -2403,7 +2403,7 @@ static inline void pgtable_pte_page_dtor(struct page *page)
>>
>> #if USE_SPLIT_PMD_PTLOCKS
>>
>> -static struct page *pmd_pgtable_page(pmd_t *pmd)
>> +static inline struct page *pmd_pgtable_page(pmd_t *pmd)
>> {
>> unsigned long mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
>> return virt_to_page((void *)((unsigned long) pmd & mask));
>
> This chunk does not appear to belong to this patch.

Should not this helper be made a 'static inline' before using it else where ?

2022-11-28 06:56:03

by Alexander Gordeev

[permalink] [raw]
Subject: Re: [PATCH] s390/mm: Use pmd_pgtable_page() helper in __gmap_segment_gaddr()

On Fri, Nov 25, 2022 at 09:15:02AM +0530, Anshuman Khandual wrote:

Hi Anshuman,

> In __gmap_segment_gaddr() pmd level page table page is being extracted from
> the pmd pointer, similar to pmd_pgtable_page() implementation. This reduces
> some redundancy by directly using pmd_pgtable_page() instead, though first
> making it available.

[...]

> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
> index 02d15c8dc92e..8947451ae021 100644
> --- a/arch/s390/mm/gmap.c
> +++ b/arch/s390/mm/gmap.c
> @@ -336,12 +336,11 @@ static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
> static unsigned long __gmap_segment_gaddr(unsigned long *entry)
> {
> struct page *page;
> - unsigned long offset, mask;
> + unsigned long offset;
>
> offset = (unsigned long) entry / sizeof(unsigned long);
> offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
> - mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
> - page = virt_to_page((void *)((unsigned long) entry & mask));
> + page = pmd_pgtable_page((pmd_t *) entry);
> return page->index + offset;
> }

Looks okay to me.

> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index e9e387caffac..5ead9e997510 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2403,7 +2403,7 @@ static inline void pgtable_pte_page_dtor(struct page *page)
>
> #if USE_SPLIT_PMD_PTLOCKS
>
> -static struct page *pmd_pgtable_page(pmd_t *pmd)
> +static inline struct page *pmd_pgtable_page(pmd_t *pmd)
> {
> unsigned long mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
> return virt_to_page((void *)((unsigned long) pmd & mask));

This chunk does not appear to belong to this patch.

Thanks!

2022-11-28 08:16:28

by Anshuman Khandual

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Subject: Re: [PATCH] s390/mm: Use pmd_pgtable_page() helper in __gmap_segment_gaddr()



On 11/28/22 12:43, Alexander Gordeev wrote:
> On Mon, Nov 28, 2022 at 12:01:06PM +0530, Anshuman Khandual wrote:
>>>> diff --git a/include/linux/mm.h b/include/linux/mm.h
>>>> index e9e387caffac..5ead9e997510 100644
>>>> --- a/include/linux/mm.h
>>>> +++ b/include/linux/mm.h
>>>> @@ -2403,7 +2403,7 @@ static inline void pgtable_pte_page_dtor(struct page *page)
>>>>
>>>> #if USE_SPLIT_PMD_PTLOCKS
>>>>
>>>> -static struct page *pmd_pgtable_page(pmd_t *pmd)
>>>> +static inline struct page *pmd_pgtable_page(pmd_t *pmd)
>>>> {
>>>> unsigned long mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
>>>> return virt_to_page((void *)((unsigned long) pmd & mask));
>>>
>>> This chunk does not appear to belong to this patch.
>>
>> Should not this helper be made a 'static inline' before using it else where ?
>
> Probably yes, but it is not kvm s390-specific change.

Right, just that the s390 change here is the first instance where this helper
is being used outside the header, hence kept them together.

>
> I guess, you wanted to make it together or as a follow-up to this one?
> https://lore.kernel.org/all/[email protected]/
>
Unless too much trouble, could we just keep it here as proposed.

2022-11-28 08:21:07

by Alexander Gordeev

[permalink] [raw]
Subject: Re: [PATCH] s390/mm: Use pmd_pgtable_page() helper in __gmap_segment_gaddr()

On Mon, Nov 28, 2022 at 12:01:06PM +0530, Anshuman Khandual wrote:
> >> diff --git a/include/linux/mm.h b/include/linux/mm.h
> >> index e9e387caffac..5ead9e997510 100644
> >> --- a/include/linux/mm.h
> >> +++ b/include/linux/mm.h
> >> @@ -2403,7 +2403,7 @@ static inline void pgtable_pte_page_dtor(struct page *page)
> >>
> >> #if USE_SPLIT_PMD_PTLOCKS
> >>
> >> -static struct page *pmd_pgtable_page(pmd_t *pmd)
> >> +static inline struct page *pmd_pgtable_page(pmd_t *pmd)
> >> {
> >> unsigned long mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
> >> return virt_to_page((void *)((unsigned long) pmd & mask));
> >
> > This chunk does not appear to belong to this patch.
>
> Should not this helper be made a 'static inline' before using it else where ?

Probably yes, but it is not kvm s390-specific change.

I guess, you wanted to make it together or as a follow-up to this one?
https://lore.kernel.org/all/[email protected]/

2022-11-28 09:18:27

by Alexander Gordeev

[permalink] [raw]
Subject: Re: [PATCH] s390/mm: Use pmd_pgtable_page() helper in __gmap_segment_gaddr()

On Mon, Nov 28, 2022 at 01:13:45PM +0530, Anshuman Khandual wrote:
> >>>> index e9e387caffac..5ead9e997510 100644
> >>>> --- a/include/linux/mm.h
> >>>> +++ b/include/linux/mm.h
> >>>> @@ -2403,7 +2403,7 @@ static inline void pgtable_pte_page_dtor(struct page *page)
> >>>>
> >>>> #if USE_SPLIT_PMD_PTLOCKS
> >>>>
> >>>> -static struct page *pmd_pgtable_page(pmd_t *pmd)
> >>>> +static inline struct page *pmd_pgtable_page(pmd_t *pmd)
> >>>> {
> >>>> unsigned long mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
> >>>> return virt_to_page((void *)((unsigned long) pmd & mask));
> >>>
> >>> This chunk does not appear to belong to this patch.
> >>
> >> Should not this helper be made a 'static inline' before using it else where ?
> >
> > Probably yes, but it is not kvm s390-specific change.
>
> Right, just that the s390 change here is the first instance where this helper
> is being used outside the header, hence kept them together.
>
> >
> > I guess, you wanted to make it together or as a follow-up to this one?
> > https://lore.kernel.org/all/[email protected]/
> >
> Unless too much trouble, could we just keep it here as proposed.

For s390 part:

Acked-by: Alexander Gordeev <[email protected]>

Thanks!