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From: Jens Axboe <[email protected]>
To: Christoph Hellwig <[email protected]>
Cc: Kanchan Joshi <[email protected]>,
	[email protected], [email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected],
	[email protected],
	Selvakumar S <[email protected]>,
	Nitesh Shetty <[email protected]>,
	Javier Gonzalez <[email protected]>
Subject: Re: [PATCH v3 4/4] io_uring: add support for zone-append
Date: Thu, 9 Jul 2020 08:05:46 -0600	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On 7/9/20 8:00 AM, Christoph Hellwig wrote:
> On Thu, Jul 09, 2020 at 07:58:04AM -0600, Jens Axboe wrote:
>>> We don't actually need any new field at all.  By the time the write
>>> returned ki_pos contains the offset after the write, and the res
>>> argument to ->ki_complete contains the amount of bytes written, which
>>> allow us to trivially derive the starting position.
>>
>> Then let's just do that instead of jumping through hoops either
>> justifying growing io_rw/io_kiocb or turning kiocb into a global
>> completion thing.
> 
> Unfortunately that is a totally separate issue - the in-kernel offset
> can be trivially calculated.  But we still need to figure out a way to
> pass it on to userspace.  The current patchset does that by abusing
> the flags, which doesn't really work as the flags are way too small.
> So we somewhere need to have an address to do the put_user to.

Right, we're just trading the 'append_offset' for a 'copy_offset_here'
pointer, which are stored in the same spot...

-- 
Jens Axboe


  reply	other threads:[~2020-07-09 14:05 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20200705185204epcas5p3adeb4fc3473c5fc0472a7396783c5267@epcas5p3.samsung.com>
2020-07-05 18:47 ` [PATCH v3 0/4] zone-append support in io-uring and aio Kanchan Joshi
     [not found]   ` <CGME20200705185211epcas5p4059d05d2fcedb91829300a7a7d03fda3@epcas5p4.samsung.com>
2020-07-05 18:47     ` [PATCH v3 1/4] fs: introduce FMODE_ZONE_APPEND and IOCB_ZONE_APPEND Kanchan Joshi
     [not found]   ` <CGME20200705185217epcas5p1cc12d4b892f057a1fe06d73a00869daa@epcas5p1.samsung.com>
2020-07-05 18:47     ` [PATCH v3 2/4] block: add zone append handling for direct I/O path Kanchan Joshi
     [not found]   ` <CGME20200705185221epcas5p28b6d060df829b751109265222285da0e@epcas5p2.samsung.com>
2020-07-05 18:47     ` [PATCH v3 3/4] block: enable zone-append for iov_iter of bvec type Kanchan Joshi
     [not found]   ` <CGME20200705185227epcas5p16fba3cb92561794b960184c89fdf2bb7@epcas5p1.samsung.com>
2020-07-05 18:47     ` [PATCH v3 4/4] io_uring: add support for zone-append Kanchan Joshi
2020-07-05 21:00       ` Jens Axboe
2020-07-05 21:09         ` Matthew Wilcox
2020-07-05 21:12           ` Jens Axboe
2020-07-06 14:10             ` Matthew Wilcox
2020-07-06 14:27               ` Jens Axboe
2020-07-06 14:32                 ` Matthew Wilcox
2020-07-06 14:33                   ` Jens Axboe
2020-07-07 15:11                   ` Kanchan Joshi
2020-07-07 15:52                     ` Matthew Wilcox
2020-07-07 16:00                       ` Christoph Hellwig
2020-07-07 20:23                       ` Kanchan Joshi
2020-07-07 20:40                         ` Jens Axboe
2020-07-07 22:18                           ` Matthew Wilcox
2020-07-07 22:37                             ` Jens Axboe
2020-07-08 12:58                               ` Kanchan Joshi
2020-07-08 14:22                                 ` Matthew Wilcox
2020-07-08 16:41                                   ` Kanchan Joshi
2020-07-08 14:54                                 ` Jens Axboe
2020-07-08 14:58                                   ` Matthew Wilcox
2020-07-08 14:59                                     ` Jens Axboe
2020-07-08 15:02                                       ` Matthew Wilcox
2020-07-08 15:06                                         ` Jens Axboe
2020-07-08 16:08                                           ` Javier González
2020-07-08 16:33                                             ` Matthew Wilcox
2020-07-08 16:38                                               ` Jens Axboe
2020-07-08 17:13                                                 ` Kanchan Joshi
2020-07-08 16:43                                               ` Javier González
2020-07-06 13:58         ` Kanchan Joshi
2020-07-09 10:15         ` Christoph Hellwig
2020-07-09 13:58           ` Jens Axboe
2020-07-09 14:00             ` Christoph Hellwig
2020-07-09 14:05               ` Jens Axboe [this message]
2020-07-09 18:36                 ` Kanchan Joshi
2020-07-09 18:50                   ` Pavel Begunkov
2020-07-09 18:53                     ` Pavel Begunkov
2020-07-09 18:50                   ` Jens Axboe
2020-07-09 19:05                     ` Kanchan Joshi
2020-07-10 13:10                       ` Christoph Hellwig
2020-07-10 13:48                         ` Matthew Wilcox
2020-07-10 13:49                           ` Christoph Hellwig
2020-07-10 13:51                             ` Matthew Wilcox
2020-07-10 14:11                               ` Kanchan Joshi
2020-07-20 16:49                                 ` Kanchan Joshi
2020-07-20 17:14                                   ` Matthew Wilcox
2020-07-20 20:17                                     ` Kanchan Joshi
2020-07-21  0:59                                       ` Damien Le Moal
2020-07-21  1:15                                         ` Matthew Wilcox
2020-07-21  1:29                                           ` Jens Axboe
2020-07-21  2:19                                           ` Damien Le Moal
2020-07-10 14:09                         ` Jens Axboe
2020-07-20 16:46                           ` Kanchan Joshi
2020-07-10 13:09                     ` Christoph Hellwig
2020-07-10 13:29                       ` Kanchan Joshi
2020-07-10 13:43                         ` Christoph Hellwig
2020-07-20 17:02                           ` Kanchan Joshi
2020-07-10 13:57                         ` Kanchan Joshi

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