linux-kernel - Re: [PATCH v4 2/3] gup: introduce unpin_user_folio_dirty

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <460e16a0-c8d9-493a-b54f-2c793c969eb1@redhat.com>
Date: Tue, 17 Jun 2025 15:45:29 +0200
From: David Hildenbrand <david@...hat.com>
To: Jason Gunthorpe <jgg@...pe.ca>, lizhe.67@...edance.com
Cc: alex.williamson@...hat.com, akpm@...ux-foundation.org, peterx@...hat.com,
 kvm@...r.kernel.org, linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH v4 2/3] gup: introduce unpin_user_folio_dirty_locked()

On 17.06.25 15:42, Jason Gunthorpe wrote:
> On Tue, Jun 17, 2025 at 12:18:20PM +0800, lizhe.67@...edance.com wrote:
> 
>> @@ -360,12 +360,7 @@ void unpin_user_page_range_dirty_lock(struct page *page, unsigned long npages,
>>   
>>   	for (i = 0; i < npages; i += nr) {
>>   		folio = gup_folio_range_next(page, npages, i, &nr);
>> -		if (make_dirty && !folio_test_dirty(folio)) {
>> -			folio_lock(folio);
>> -			folio_mark_dirty(folio);
>> -			folio_unlock(folio);
>> -		}
>> -		gup_put_folio(folio, nr, FOLL_PIN);
>> +		unpin_user_folio_dirty_locked(folio, nr, make_dirty);
>>   	}
> 
> I don't think we should call an exported function here - this is a
> fast path for rdma and iommfd, I don't want to see it degrade to save
> three duplicated lines :\

Any way to quantify? In theory, the compiler could still optimize this 
within the same file, no?

> 
> Make the new function an inline?

That of course also works.

-- 
Cheers,

David / dhildenb