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Subject: Re: [PATCH v2 40/42] example for future extension: mm:gup/writeback:
 add callbacks for inaccessible pages: source indication
References: <20200214222658.12946-1-borntraeger@de.ibm.com>
 <20200214222658.12946-41-borntraeger@de.ibm.com>
 <20200217141511.GA14704@oc3748833570.ibm.com>
From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Mon, 17 Feb 2020 15:38:30 +0100
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To: Ulrich Weigand <uweigand@de.ibm.com>
Cc: Janosch Frank <frankja@linux.vnet.ibm.com>, Andrew Morton <akpm@linux-foundation.org>, KVM <kvm@vger.kernel.org>, Cornelia Huck <cohuck@redhat.com>, David Hildenbrand <david@redhat.com>, Thomas Huth <thuth@redhat.com>, Ulrich Weigand <Ulrich.Weigand@de.ibm.com>, Claudio Imbrenda <imbrenda@linux.ibm.com>, linux-s390 <linux-s390@vger.kernel.org>, Michael Mueller <mimu@linux.ibm.com>, Vasily Gorbik <gor@linux.ibm.com>, Andrea Arcangeli <aarcange@redhat.com>, linux-mm@kvack.org, Will Deacon <will@kernel.org>, Sean Christopherson <sean.j.christopherson@intel.com>



On 17.02.20 15:15, Ulrich Weigand wrote:
> On Fri, Feb 14, 2020 at 05:26:56PM -0500, Christian Borntraeger wrote:
>> +enum access_type {
>> +	MAKE_ACCESSIBLE_GENERIC,
>> +	MAKE_ACCESSIBLE_GET,
>> +	MAKE_ACCESSIBLE_GET_FAST,
>> +	MAKE_ACCESSIBLE_WRITEBACK
>> +};
>>  #ifndef HAVE_ARCH_MAKE_PAGE_ACCESSIBLE
>> -static inline int arch_make_page_accessible(struct page *page)
>> +static inline int arch_make_page_accessible(struct page *page, int where)
> 
> If we want to make this distinction, wouldn't it be simpler to just
> use different function names, like
>   arch_make_page_accessible_for_writeback
>   arch_make_page_accessible_for_gup
> etc.

Agreed.
I would suggest to do these changes when somebody needs them, though.
On the other hand, Patch 39 (the error handling) is something that we
could merge now.