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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Linux MM <linux-mm@kvack.org>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	linux-nvdimm <linux-nvdimm@lists.01.org>
Subject: Re: [PATCH] mm/nvdimm: Use correct alignment when looking at first pfn from a region
Date: Tue, 14 May 2019 10:11:47 +0530	[thread overview]
Message-ID: <925e41ad-cc57-bc03-a2b6-6913c9e98abf@linux.ibm.com> (raw)
In-Reply-To: <CAPcyv4hgNUDxjgYNkxOXJ9hfLb6z2+E1yasNoZNDKFUxkCzWLA@mail.gmail.com>

On 5/14/19 9:59 AM, Dan Williams wrote:
> On Mon, May 13, 2019 at 7:55 PM Aneesh Kumar K.V
> <aneesh.kumar@linux.ibm.com> wrote:
>>
>> We already add the start_pad to the resource->start but fails to section
>> align the start. This make sure with altmap we compute the right first
>> pfn when start_pad is zero and we are doing an align down of start address.
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> ---
>>   kernel/memremap.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/memremap.c b/kernel/memremap.c
>> index a856cb5ff192..23d77b60e728 100644
>> --- a/kernel/memremap.c
>> +++ b/kernel/memremap.c
>> @@ -59,9 +59,9 @@ static unsigned long pfn_first(struct dev_pagemap *pgmap)
>>   {
>>          const struct resource *res = &pgmap->res;
>>          struct vmem_altmap *altmap = &pgmap->altmap;
>> -       unsigned long pfn;
>> +       unsigned long pfn = PHYS_PFN(res->start);
>>
>> -       pfn = res->start >> PAGE_SHIFT;
>> +       pfn = SECTION_ALIGN_DOWN(pfn);
> 
> This does not seem right to me it breaks the assumptions of where the
> first expected valid pfn occurs in the passed in range.
> 

How do we define the first valid pfn? Isn't that at pfn_sb->dataoff ?

-aneesh

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Linux-nvdimm@lists.01.org
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WARNING: multiple messages have this Message-ID (diff)
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-nvdimm <linux-nvdimm@lists.01.org>,
	Linux MM <linux-mm@kvack.org>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] mm/nvdimm: Use correct alignment when looking at first pfn from a region
Date: Tue, 14 May 2019 10:11:47 +0530	[thread overview]
Message-ID: <925e41ad-cc57-bc03-a2b6-6913c9e98abf@linux.ibm.com> (raw)
In-Reply-To: <CAPcyv4hgNUDxjgYNkxOXJ9hfLb6z2+E1yasNoZNDKFUxkCzWLA@mail.gmail.com>

On 5/14/19 9:59 AM, Dan Williams wrote:
> On Mon, May 13, 2019 at 7:55 PM Aneesh Kumar K.V
> <aneesh.kumar@linux.ibm.com> wrote:
>>
>> We already add the start_pad to the resource->start but fails to section
>> align the start. This make sure with altmap we compute the right first
>> pfn when start_pad is zero and we are doing an align down of start address.
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> ---
>>   kernel/memremap.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/memremap.c b/kernel/memremap.c
>> index a856cb5ff192..23d77b60e728 100644
>> --- a/kernel/memremap.c
>> +++ b/kernel/memremap.c
>> @@ -59,9 +59,9 @@ static unsigned long pfn_first(struct dev_pagemap *pgmap)
>>   {
>>          const struct resource *res = &pgmap->res;
>>          struct vmem_altmap *altmap = &pgmap->altmap;
>> -       unsigned long pfn;
>> +       unsigned long pfn = PHYS_PFN(res->start);
>>
>> -       pfn = res->start >> PAGE_SHIFT;
>> +       pfn = SECTION_ALIGN_DOWN(pfn);
> 
> This does not seem right to me it breaks the assumptions of where the
> first expected valid pfn occurs in the passed in range.
> 

How do we define the first valid pfn? Isn't that at pfn_sb->dataoff ?

-aneesh


WARNING: multiple messages have this Message-ID (diff)
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Linux MM <linux-mm@kvack.org>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	linux-nvdimm <linux-nvdimm@lists.01.org>
Subject: Re: [PATCH] mm/nvdimm: Use correct alignment when looking at first pfn from a region
Date: Tue, 14 May 2019 10:11:47 +0530	[thread overview]
Message-ID: <925e41ad-cc57-bc03-a2b6-6913c9e98abf@linux.ibm.com> (raw)
In-Reply-To: <CAPcyv4hgNUDxjgYNkxOXJ9hfLb6z2+E1yasNoZNDKFUxkCzWLA@mail.gmail.com>

On 5/14/19 9:59 AM, Dan Williams wrote:
> On Mon, May 13, 2019 at 7:55 PM Aneesh Kumar K.V
> <aneesh.kumar@linux.ibm.com> wrote:
>>
>> We already add the start_pad to the resource->start but fails to section
>> align the start. This make sure with altmap we compute the right first
>> pfn when start_pad is zero and we are doing an align down of start address.
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> ---
>>   kernel/memremap.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/memremap.c b/kernel/memremap.c
>> index a856cb5ff192..23d77b60e728 100644
>> --- a/kernel/memremap.c
>> +++ b/kernel/memremap.c
>> @@ -59,9 +59,9 @@ static unsigned long pfn_first(struct dev_pagemap *pgmap)
>>   {
>>          const struct resource *res = &pgmap->res;
>>          struct vmem_altmap *altmap = &pgmap->altmap;
>> -       unsigned long pfn;
>> +       unsigned long pfn = PHYS_PFN(res->start);
>>
>> -       pfn = res->start >> PAGE_SHIFT;
>> +       pfn = SECTION_ALIGN_DOWN(pfn);
> 
> This does not seem right to me it breaks the assumptions of where the
> first expected valid pfn occurs in the passed in range.
> 

How do we define the first valid pfn? Isn't that at pfn_sb->dataoff ?

-aneesh


  reply	other threads:[~2019-05-14  4:41 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-14  2:55 [PATCH] mm/nvdimm: Use correct alignment when looking at first pfn from a region Aneesh Kumar K.V
2019-05-14  2:55 ` Aneesh Kumar K.V
2019-05-14  2:55 ` Aneesh Kumar K.V
2019-05-14  4:29 ` Dan Williams
2019-05-14  4:29   ` Dan Williams
2019-05-14  4:29   ` Dan Williams
2019-05-14  4:41   ` Aneesh Kumar K.V [this message]
2019-05-14  4:41     ` Aneesh Kumar K.V
2019-05-14  4:41     ` Aneesh Kumar K.V
2019-05-27  9:35     ` Aneesh Kumar K.V
2019-05-27  9:35       ` Aneesh Kumar K.V
2019-05-27  9:35       ` Aneesh Kumar K.V

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