linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "Andreas Grünbacher" <andreas.gruenbacher@gmail.com>
To: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Cc: Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Christoph Hellwig <hch@infradead.org>,
	Dave Chinner <david@fromorbit.com>,
	willy@infradead.org, Andrew Morton <akpm@linux-foundation.org>,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	William Kucharski <william.kucharski@oracle.com>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Andreas Gruenbacher <agruenba@redhat.com>,
	Yang Shi <yang.shi@linux.alibaba.com>,
	Yafang Shao <laoar.shao@gmail.com>, Song Liu <song@kernel.org>,
	linux-raid@vger.kernel.org, Chris Mason <clm@fb.com>,
	Josef Bacik <josef@toxicpanda.com>,
	David Sterba <dsterba@suse.com>,
	linux-btrfs@vger.kernel.org,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Jaegeuk Kim <jaegeuk@kernel.org>, Chao Yu <chao@kernel.org>,
	linux-f2fs-devel@lists.sourceforge.net,
	linux-xfs <linux-xfs@vger.kernel.org>,
	Anton Altaparmakov <anton@tuxera.com>,
	linux-ntfs-dev@lists.sourceforge.net,
	Mike Marshall <hubcap@omnibond.com>,
	Martin Brandenburg <martin@omnibond.com>,
	devel@lists.orangefs.org, Thomas Gleixner <tglx@linutronix.de>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Roman Gushchin <guro@fb.com>, Andreas Dilger <adilger@dilger.ca>
Subject: Re: [RFC PATCH V2 1/9] include/linux/pagemap.h: introduce attach/clear_page_private
Date: Fri, 1 May 2020 00:10:15 +0200	[thread overview]
Message-ID: <CAHpGcMKdzSBGZTRwuoBTuCFUX44egmutvCr9LcjYW7KpWxmhHA@mail.gmail.com> (raw)
In-Reply-To: <20200430214450.10662-2-guoqing.jiang@cloud.ionos.com>

Hi,

Am Do., 30. Apr. 2020 um 23:56 Uhr schrieb Guoqing Jiang
<guoqing.jiang@cloud.ionos.com>:
> The logic in attach_page_buffers and  __clear_page_buffers are quite
> paired, but
>
> 1. they are located in different files.
>
> 2. attach_page_buffers is implemented in buffer_head.h, so it could be
>    used by other files. But __clear_page_buffers is static function in
>    buffer.c and other potential users can't call the function, md-bitmap
>    even copied the function.
>
> So, introduce the new attach/clear_page_private to replace them. With
> the new pair of function, we will remove the usage of attach_page_buffers
> and  __clear_page_buffers in next patches. Thanks for the new names from
> Christoph Hellwig.
>
> Suggested-by: Matthew Wilcox <willy@infradead.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
> Cc: William Kucharski <william.kucharski@oracle.com>
> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> Cc: Andreas Gruenbacher <agruenba@redhat.com>
> Cc: Yang Shi <yang.shi@linux.alibaba.com>
> Cc: Yafang Shao <laoar.shao@gmail.com>
> Cc: Song Liu <song@kernel.org>
> Cc: linux-raid@vger.kernel.org
> Cc: Chris Mason <clm@fb.com>
> Cc: Josef Bacik <josef@toxicpanda.com>
> Cc: David Sterba <dsterba@suse.com>
> Cc: linux-btrfs@vger.kernel.org
> Cc: Alexander Viro <viro@zeniv.linux.org.uk>
> Cc: Jaegeuk Kim <jaegeuk@kernel.org>
> Cc: Chao Yu <chao@kernel.org>
> Cc: linux-f2fs-devel@lists.sourceforge.net
> Cc: Christoph Hellwig <hch@infradead.org>
> Cc: linux-xfs@vger.kernel.org
> Cc: Anton Altaparmakov <anton@tuxera.com>
> Cc: linux-ntfs-dev@lists.sourceforge.net
> Cc: Mike Marshall <hubcap@omnibond.com>
> Cc: Martin Brandenburg <martin@omnibond.com>
> Cc: devel@lists.orangefs.org
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Cc: Roman Gushchin <guro@fb.com>
> Cc: Andreas Dilger <adilger@dilger.ca>
> Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
> ---
> RFC -> RFC V2:  Address the comments from Christoph Hellwig
> 1. change function names to attach/clear_page_private and add comments.
> 2. change the return type of attach_page_private.
>
>  include/linux/pagemap.h | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
>
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index a8f7bd8ea1c6..2e515f210b18 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -205,6 +205,41 @@ static inline int page_cache_add_speculative(struct page *page, int count)
>         return __page_cache_add_speculative(page, count);
>  }
>
> +/**
> + * attach_page_private - attach data to page's private field and set PG_private.
> + * @page: page to be attached and set flag.
> + * @data: data to attach to page's private field.
> + *
> + * Need to take reference as mm.h said "Setting PG_private should also increment
> + * the refcount".
> + */
> +static inline void attach_page_private(struct page *page, void *data)
> +{
> +       get_page(page);
> +       set_page_private(page, (unsigned long)data);
> +       SetPagePrivate(page);
> +}
> +
> +/**
> + * clear_page_private - clear page's private field and PG_private.
> + * @page: page to be cleared.
> + *
> + * The counterpart function of attach_page_private.
> + * Return: private data of page or NULL if page doesn't have private data.
> + */
> +static inline void *clear_page_private(struct page *page)
> +{
> +       void *data = (void *)page_private(page);
> +
> +       if (!PagePrivate(page))
> +               return NULL;
> +       ClearPagePrivate(page);
> +       set_page_private(page, 0);
> +       put_page(page);
> +
> +       return data;
> +}
> +

I like this in general, but the name clear_page_private suggests that
this might be the inverse operation of set_page_private, which it is
not. So maybe this can be renamed to detach_page_private to more
clearly indicate that it pairs with attach_page_private?

>  #ifdef CONFIG_NUMA
>  extern struct page *__page_cache_alloc(gfp_t gfp);
>  #else
> --
> 2.17.1
>

Thanks,
Andreas

  reply	other threads:[~2020-04-30 22:10 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-30 21:44 [RFC PATCH V2 0/9] Introduce attach/clear_page_private to cleanup code Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 1/9] include/linux/pagemap.h: introduce attach/clear_page_private Guoqing Jiang
2020-04-30 22:10   ` Andreas Grünbacher [this message]
2020-05-01  6:38     ` Guoqing Jiang
2020-04-30 22:13   ` Matthew Wilcox
2020-05-01  1:42     ` Al Viro
2020-05-01  1:49       ` Al Viro
2020-05-01  6:41         ` Guoqing Jiang
2020-05-01  6:39     ` Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 2/9] md: remove __clear_page_buffers and use attach/clear_page_private Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 3/9] btrfs: " Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 4/9] fs/buffer.c: " Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 5/9] f2fs: " Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 6/9] iomap: " Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 7/9] ntfs: replace attach_page_buffers with attach_page_private Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 8/9] orangefs: use attach/clear_page_private Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 9/9] buffer_head.h: remove attach_page_buffers Guoqing Jiang
2020-05-01 22:16 ` [RFC PATCH V2 0/9] Introduce attach/clear_page_private to cleanup code Matthew Wilcox
2020-05-01 22:42   ` Guoqing Jiang
2020-05-02  0:41     ` Matthew Wilcox
2020-05-02  8:56       ` Guoqing Jiang

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=CAHpGcMKdzSBGZTRwuoBTuCFUX44egmutvCr9LcjYW7KpWxmhHA@mail.gmail.com \
    --to=andreas.gruenbacher@gmail.com \
    --cc=adilger@dilger.ca \
    --cc=agruenba@redhat.com \
    --cc=akpm@linux-foundation.org \
    --cc=anton@tuxera.com \
    --cc=bigeasy@linutronix.de \
    --cc=chao@kernel.org \
    --cc=clm@fb.com \
    --cc=darrick.wong@oracle.com \
    --cc=david@fromorbit.com \
    --cc=devel@lists.orangefs.org \
    --cc=dsterba@suse.com \
    --cc=guoqing.jiang@cloud.ionos.com \
    --cc=guro@fb.com \
    --cc=hch@infradead.org \
    --cc=hubcap@omnibond.com \
    --cc=jaegeuk@kernel.org \
    --cc=josef@toxicpanda.com \
    --cc=kirill.shutemov@linux.intel.com \
    --cc=laoar.shao@gmail.com \
    --cc=linux-btrfs@vger.kernel.org \
    --cc=linux-f2fs-devel@lists.sourceforge.net \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-ntfs-dev@lists.sourceforge.net \
    --cc=linux-raid@vger.kernel.org \
    --cc=linux-xfs@vger.kernel.org \
    --cc=martin@omnibond.com \
    --cc=song@kernel.org \
    --cc=tglx@linutronix.de \
    --cc=viro@zeniv.linux.org.uk \
    --cc=william.kucharski@oracle.com \
    --cc=willy@infradead.org \
    --cc=yang.shi@linux.alibaba.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).