linux-kernel - Re: [PATCH 19/60] fs/buffer: comment on direct access to bvec table

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] [day] [month] [year] [list]

Message-ID: <CACVXFVOGHDX17iXGo6-kPeGpS_sAq79O=9A6uB3sHDZ_Qshi-Q@mail.gmail.com>
Date:   Tue, 1 Nov 2016 07:12:30 +0800
From:   Ming Lei <tom.leiming@...il.com>
To:     Christoph Hellwig <hch@...radead.org>
Cc:     Jens Axboe <axboe@...com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-block <linux-block@...r.kernel.org>,
        Linux FS Devel <linux-fsdevel@...r.kernel.org>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Kent Overstreet <kent.overstreet@...il.com>
Subject: Re: [PATCH 19/60] fs/buffer: comment on direct access to bvec table

On Mon, Oct 31, 2016 at 11:35 PM, Christoph Hellwig <hch@...radead.org> wrote:
>
> I think we'll just need a version zero_fill_bio with a length argument
> and let that handle all the bvec access.  I have vague memories that
> Kent posted one a while ago, Ccing him.

I will try to find zero_fill_bio() in Kent's tree later.

BTW, patch 59 switches to use bvec iterator to do that too.

>
> On Sat, Oct 29, 2016 at 04:08:18PM +0800, Ming Lei wrote:
>> Signed-off-by: Ming Lei <tom.leiming@...il.com>
>> ---
>>  fs/buffer.c | 7 ++++++-
>>  1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/buffer.c b/fs/buffer.c
>> index b205a629001d..81c3793948b4 100644
>> --- a/fs/buffer.c
>> +++ b/fs/buffer.c
>> @@ -3018,8 +3018,13 @@ static void end_bio_bh_io_sync(struct bio *bio)
>>  void guard_bio_eod(int op, struct bio *bio)
>>  {
>>       sector_t maxsector;
>> -     struct bio_vec *bvec = &bio->bi_io_vec[bio->bi_vcnt - 1];
>>       unsigned truncated_bytes;
>> +     /*
>> +      * It is safe to truncate the last bvec in the following way
>> +      * even though multipage bvec is supported, but we need to
>> +      * fix the parameters passed to zero_user().
>> +      */
>> +     struct bio_vec *bvec = &bio->bi_io_vec[bio->bi_vcnt - 1];
>>
>>       maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9;
>>       if (!maxsector)
>> --
>> 2.7.4
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-block" in
>> the body of a message to majordomo@...r.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> ---end quoted text---


thanks,
Ming Lei