Commit b03143ac authored Jun 01, 2020 by Guoqing Jiang Committed by Linus Torvalds Jun 02, 2020

include/linux/pagemap.h: introduce attach/detach_page_private



Patch series "Introduce attach/detach_page_private to cleanup code".

This patch (of 10):

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/detach_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 suggestions about
the function name from Alexander Viro, Andreas Grünbacher, Christoph
Hellwig and Matthew Wilcox.

Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: 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: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Chao Yu <chao@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Anton Altaparmakov <anton@tuxera.com>
Cc: Mike Marshall <hubcap@omnibond.com>
Cc: Martin Brandenburg <martin@omnibond.com>
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>
Cc: Chao Yu <yuchao0@huawei.com>
Cc: Dave Chinner <david@fromorbit.com>
Link: http://lkml.kernel.org/r/20200517214718.468-1-guoqing.jiang@cloud.ionos.com
Link: http://lkml.kernel.org/r/20200517214718.468-2-guoqing.jiang@cloud.ionos.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 9d24a13a

include/linux/pagemap.h

+37 −0

Original line number	Diff line number	Diff line
		@@ -208,6 +208,43 @@ static inline int page_cache_add_speculative(struct page *page, int count)
		return __page_cache_add_speculative(page, count);
		}

		/**
		* attach_page_private - Attach private data to a page.
		* @page: Page to attach data to.
		* @data: Data to attach to page.
		*
		* Attaching private data to a page increments the page's reference count.
		* The data must be detached before the page will be freed.
		*/
		static inline void attach_page_private(struct page page, void data)
		{
		get_page(page);
		set_page_private(page, (unsigned long)data);
		SetPagePrivate(page);
		}

		/**
		* detach_page_private - Detach private data from a page.
		* @page: Page to detach data from.
		*
		* Removes the data that was previously attached to the page and decrements
		* the refcount on the page.
		*
		* Return: Data that was attached to the page.
		*/
		static inline void detach_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;
		}

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

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