From: Christoph Hellwig <hch@infradead.org>
To: Michal Kubecek <mkubecek@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] eventfd: convert to ->write_iter()
Date: Wed, 18 Nov 2020 15:18:06 +0000 [thread overview]
Message-ID: <20201118151806.GA25804@infradead.org> (raw)
In-Reply-To: <8a4f07e6ec47b681a32c6df5d463857e67bfc965.1605690824.git.mkubecek@suse.cz>
On Wed, Nov 18, 2020 at 10:19:17AM +0100, Michal Kubecek wrote:
> While eventfd ->read() callback was replaced by ->read_iter() recently,
> it still provides ->write() for writes. Since commit 4d03e3cc5982 ("fs:
> don't allow kernel reads and writes without iter ops"), this prevents
> kernel_write() to be used for eventfd and with set_fs() removal,
> ->write() cannot be easily called directly with a kernel buffer.
>
> According to eventfd(2), eventfd descriptors are supposed to be (also)
> used by kernel to notify userspace applications of events which now
> requires ->write_iter() op to be available (and ->write() not to be).
> Therefore convert eventfd_write() to ->write_iter() semantics. This
> patch also cleans up the code in a similar way as commit 12aceb89b0bc
> ("eventfd: convert to f_op->read_iter()") did in read_iter().
A far as I can tell we don't have an in-tree user that writes to an
eventfd. We can merge something like this once there is a user.
next prev parent reply other threads:[~2020-11-18 15:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-18 9:19 [PATCH] eventfd: convert to ->write_iter() Michal Kubecek
2020-11-18 15:18 ` Christoph Hellwig [this message]
2020-11-18 19:59 ` Michal Kubecek
2020-11-18 21:27 ` Jens Axboe
2020-11-18 23:18 ` Michal Kubecek
2020-11-18 23:25 ` Jens Axboe
2020-11-18 23:34 ` Michal Kubecek
2020-11-22 14:42 ` [eventfd] 5cb13cb023: will-it-scale.per_thread_ops -6.3% regression kernel test robot
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201118151806.GA25804@infradead.org \
--to=hch@infradead.org \
--cc=axboe@kernel.dk \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mkubecek@suse.cz \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).