From: Christoph Hellwig <hch@lst.de>
To: Nikolay Borisov <nborisov@suse.com>
Cc: Christoph Hellwig <hch@lst.de>, Chris Mason <clm@fb.com>,
Josef Bacik <josef@toxicpanda.com>,
David Sterba <dsterba@suse.com>,
"Darrick J. Wong" <djwong@kernel.org>,
linux-btrfs@vger.kernel.org, linux-xfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 2/5] iomap: add per-iomap_iter private data
Date: Thu, 5 May 2022 17:06:41 +0200 [thread overview]
Message-ID: <20220505150641.GA19810@lst.de> (raw)
In-Reply-To: <9d53e1bd-b370-cc8c-5194-fa084b887ecc@suse.com>
On Thu, May 05, 2022 at 11:06:50AM +0300, Nikolay Borisov wrote:
>> @@ -520,6 +520,14 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
>> dio->submit.waiter = current;
>> dio->submit.poll_bio = NULL;
>> + /*
>> + * Transfer the private data that was passed by the caller to the
>> + * iomap_iter, and clear it in the iocb, as iocb->private will be
>> + * used for polled bio completion later.
>> + */
>> + iomi.private = iocb->private;
>> + WRITE_ONCE(iocb->private, NULL);
>
> nit: Why use WRITE_ONCE here? Generaly when it's used it will suggest to
> the reader something funny is going on with accessing that variable without
> holding a particular lock?
Because we use WRITE_ONCE on iocb->private later on when we use it to
store the bio that is polled for, and we really want the store that
clears it to NULL to be done before we start dealing with bio submission.
next prev parent reply other threads:[~2022-05-05 15:06 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-04 16:23 reduce memory allocation in the btrfs direct I/O path Christoph Hellwig
2022-05-04 16:23 ` [PATCH 1/5] iomap: allow the file system to provide a bio_set for direct I/O Christoph Hellwig
2022-05-05 15:38 ` Darrick J. Wong
2022-05-04 16:23 ` [PATCH 2/5] iomap: add per-iomap_iter private data Christoph Hellwig
2022-05-05 8:06 ` Nikolay Borisov
2022-05-05 15:06 ` Christoph Hellwig [this message]
2022-05-05 15:41 ` Darrick J. Wong
2022-05-05 15:45 ` Christoph Hellwig
2022-05-05 16:32 ` Darrick J. Wong
2022-05-05 18:15 ` Christoph Hellwig
2022-05-05 18:18 ` Darrick J. Wong
2022-05-04 16:23 ` [PATCH 3/5] btrfs: add a btrfs_dio_rw wrapper Christoph Hellwig
2022-05-04 16:23 ` [PATCH 4/5] btrfs: allocate dio_data on stack Christoph Hellwig
2022-05-04 16:23 ` [PATCH 5/5] btrfs: allocate the btrfs_dio_private as part of the iomap dio bio Christoph Hellwig
2022-05-05 8:12 ` Nikolay Borisov
2022-05-05 15:07 ` Christoph Hellwig
2022-05-05 15:20 ` David Sterba
2022-05-05 15:52 ` David Sterba
2022-05-05 8:33 ` reduce memory allocation in the btrfs direct I/O path Nikolay Borisov
2022-05-05 15:55 ` David Sterba
2022-05-06 17:18 ` Darrick J. Wong
2022-05-07 5:26 ` Christoph Hellwig
2022-05-09 18:46 ` David Sterba
2022-05-10 3:33 ` Darrick J. Wong
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=20220505150641.GA19810@lst.de \
--to=hch@lst.de \
--cc=clm@fb.com \
--cc=djwong@kernel.org \
--cc=dsterba@suse.com \
--cc=josef@toxicpanda.com \
--cc=linux-btrfs@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-xfs@vger.kernel.org \
--cc=nborisov@suse.com \
/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).