linux-kernel - Re: [PATCH 08/16] dm-writecache: use bvec_kmap_local instead of bvec_kmap

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, 8 Jun 2021 18:38:02 +0200
From:   Christoph Hellwig <hch@....de>
To:     Bart Van Assche <bvanassche@....org>
Cc:     Christoph Hellwig <hch@....de>, Jens Axboe <axboe@...nel.dk>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Geoff Levand <geoff@...radead.org>,
        Ilya Dryomov <idryomov@...il.com>,
        Dongsheng Yang <dongsheng.yang@...ystack.cn>,
        Mike Snitzer <snitzer@...hat.com>,
        Ira Weiny <ira.weiny@...el.com>, dm-devel@...hat.com,
        linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-block@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        ceph-devel@...r.kernel.org
Subject: Re: [PATCH 08/16] dm-writecache: use bvec_kmap_local instead of
 bvec_kmap_irq

On Tue, Jun 08, 2021 at 09:30:56AM -0700, Bart Van Assche wrote:
> >From one of the functions called by kunmap_local():
> 
> unsigned long addr = (unsigned long) vaddr & PAGE_MASK;
> 
> This won't work well if bvec->bv_offset >= PAGE_SIZE I assume?

It won't indeed.  Both the existing and new helpers operate on single
page bvecs only, and all callers only use those.  I should have
probably mentioned that in the cover letter and documented the
assumptions in the code, though.