linux-kernel - Re: [PATCH -V2 4/5] swap: remove get/put_swap_device() in __swap

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]

Date:   Tue, 23 May 2023 08:56:11 +0800
From:   "Huang, Ying" <ying.huang@...el.com>
To:     David Hildenbrand <david@...hat.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Hugh Dickins <hughd@...gle.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Matthew Wilcox <willy@...radead.org>,
        Michal Hocko <mhocko@...e.com>,
        Minchan Kim <minchan@...nel.org>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Yang Shi <shy828301@...il.com>, Yu Zhao <yuzhao@...gle.com>
Subject: Re: [PATCH -V2 4/5] swap: remove get/put_swap_device() in
 __swap_duplicate()

David Hildenbrand <david@...hat.com> writes:

> On 22.05.23 09:09, Huang Ying wrote:
>> __swap_duplicate() is called by
>> - swap_shmem_alloc(): the page lock of the swap cache is held.
>
> page lock of the swap cache? Did you really mean to say that or am I
> confused?
>
> "Page lock of the page that is in the swap cache?"

Sorry for my poor English. Or make it shorter?

"the folio in the swap cache is locked"

Best Regards,
Huang, Ying

>> - copy_nonpresent_pte() -> swap_duplicate() and try_to_unmap_one()
>> ->
>>    swap_duplicate(): the page table lock is held.
>> - __read_swap_cache_async() -> swapcache_prepare(): enclosed with
>>    get/put_swap_device() in __read_swap_cache_async() already.
>> So, it's safe to remove get/put_swap_device() in __swap_duplicate().