linux-kernel - Re: [PATCH 3/3] io_uring: add support for zone-append

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:   Thu, 18 Jun 2020 10:35:29 +0200
From:   "javier.gonz@...sung.com" <javier@...igon.com>
To:     Damien Le Moal <Damien.LeMoal@....com>
Cc:     Kanchan Joshi <joshi.k@...sung.com>,
        "axboe@...nel.dk" <axboe@...nel.dk>,
        "viro@...iv.linux.org.uk" <viro@...iv.linux.org.uk>,
        "bcrl@...ck.org" <bcrl@...ck.org>,
        "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-aio@...ck.org" <linux-aio@...ck.org>,
        "io-uring@...r.kernel.org" <io-uring@...r.kernel.org>,
        "linux-block@...r.kernel.org" <linux-block@...r.kernel.org>,
        "selvakuma.s1@...sung.com" <selvakuma.s1@...sung.com>,
        "nj.shetty@...sung.com" <nj.shetty@...sung.com>
Subject: Re: [PATCH 3/3] io_uring: add support for zone-append

On 18.06.2020 07:39, Damien Le Moal wrote:
>On 2020/06/18 2:27, Kanchan Joshi wrote:
>> From: Selvakumar S <selvakuma.s1@...sung.com>
>>
>> Introduce three new opcodes for zone-append -
>>
>>    IORING_OP_ZONE_APPEND     : non-vectord, similiar to IORING_OP_WRITE
>>    IORING_OP_ZONE_APPENDV    : vectored, similar to IORING_OP_WRITEV
>>    IORING_OP_ZONE_APPEND_FIXED : append using fixed-buffers
>>
>> Repurpose cqe->flags to return zone-relative offset.
>>
>> Signed-off-by: SelvaKumar S <selvakuma.s1@...sung.com>
>> Signed-off-by: Kanchan Joshi <joshi.k@...sung.com>
>> Signed-off-by: Nitesh Shetty <nj.shetty@...sung.com>
>> Signed-off-by: Javier Gonzalez <javier.gonz@...sung.com>
>> ---
>>  fs/io_uring.c                 | 72 +++++++++++++++++++++++++++++++++++++++++--
>>  include/uapi/linux/io_uring.h |  8 ++++-
>>  2 files changed, 77 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>> index 155f3d8..c14c873 100644
>> --- a/fs/io_uring.c
>> +++ b/fs/io_uring.c
>> @@ -649,6 +649,10 @@ struct io_kiocb {
>>  	unsigned long		fsize;
>>  	u64			user_data;
>>  	u32			result;
>> +#ifdef CONFIG_BLK_DEV_ZONED
>> +	/* zone-relative offset for append, in bytes */
>> +	u32			append_offset;
>
>this can overflow. u64 is needed.

We chose to do it this way to start with because struct io_uring_cqe
only has space for u32 when we reuse the flags.

We can of course create a new cqe structure, but that will come with
larger changes to io_uring for supporting append.

Do you believe this is a better approach?

Javier