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From: Christoph Hellwig <hch@lst.de>
To: Damien Le Moal <Damien.LeMoal@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>,
	Johannes Thumshirn <Johannes.Thumshirn@wdc.com>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	Jens Axboe <axboe@kernel.dk>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>
Subject: Re: [PATCH 1/2] fs: fix kiocb ki_complete interface
Date: Mon, 20 Jul 2020 15:47:17 +0200	[thread overview]
Message-ID: <20200720134717.GA3908@lst.de> (raw)
In-Reply-To: <CY4PR04MB375119332AF668A4A0368DF9E77B0@CY4PR04MB3751.namprd04.prod.outlook.com>

On Mon, Jul 20, 2020 at 01:43:43PM +0000, Damien Le Moal wrote:
> On 2020/07/20 22:38, Christoph Hellwig wrote:
> > On Mon, Jul 20, 2020 at 10:21:17PM +0900, Johannes Thumshirn wrote:
> >> From: Damien Le Moal <damien.lemoal@wdc.com>
> >>
> >> The res and res2 fields of struct io_event are signed 64 bits values
> >> (__s64 type). Allow the ki_complete method of struct kiocb to set 64
> >> bits values in these fields by changin its interface from the long type
> >> to long long.
> > 
> > Which doesn't help if the consumers can't deal with these values.
> > But that shouldn't even be required for using zone append anyway..
> > 
> 
> Not sure what you mean...
> 
> res2 is used to pass back to the user the written file offset, 64bits Bytes
> value, for aio case (io_submit()/io_getevent()). The change does not break user
> interface at all, no changes needed to any system call. The patch  just enables
> passing that 64bit byte offset. The consumer of it would be the user
> application, and yes, it does need to know what it is doing. But if it is using
> zonefs, likely, the application knows.

Please start a discussion on this ABI on the linux-aio and linux-api
lists.  If we support that for zonefs we should also support it for
other direct I/O writes.  And I'm not sure an API that only works
with aio and not io_uring is going to win a lot of friends these days.

  reply	other threads:[~2020-07-20 13:47 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-20 13:21 [PATCH 0/2] zonefs: use zone-append for aio with rwf append Johannes Thumshirn
2020-07-20 13:21 ` [PATCH 1/2] fs: fix kiocb ki_complete interface Johannes Thumshirn
2020-07-20 13:38   ` Christoph Hellwig
2020-07-20 13:43     ` Damien Le Moal
2020-07-20 13:47       ` Christoph Hellwig [this message]
2020-07-20 13:21 ` [PATCH 2/2] zonefs: use zone-append for AIO as well Johannes Thumshirn
2020-07-20 13:45   ` Christoph Hellwig
2020-07-20 16:48     ` Johannes Thumshirn
2020-07-21  5:54       ` Christoph Hellwig
2020-07-22 12:43         ` Johannes Thumshirn
2020-07-22 13:02           ` Damien Le Moal
2020-07-22 14:53             ` Christoph Hellwig
2020-07-22 14:51           ` Christoph Hellwig
2020-07-22 15:00             ` Johannes Thumshirn
2020-07-24 13:57             ` Kanchan Joshi
2020-07-27  3:12               ` Damien Le Moal
2020-07-21 12:43   ` Kanchan Joshi
2020-07-22 14:32     ` Johannes Thumshirn

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