Hi, Am Do., 30. Apr. 2020 um 23:56 Uhr schrieb Guoqing Jiang <[email protected]>: > 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 <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: "Darrick J. Wong" <[email protected]> > Cc: William Kucharski <[email protected]> > Cc: "Kirill A. Shutemov" <[email protected]> > Cc: Andreas Gruenbacher <[email protected]> > Cc: Yang Shi <[email protected]> > Cc: Yafang Shao <[email protected]> > Cc: Song Liu <[email protected]> > Cc: [email protected] > Cc: Chris Mason <[email protected]> > Cc: Josef Bacik <[email protected]> > Cc: David Sterba <[email protected]> > Cc: [email protected] > Cc: Alexander Viro <[email protected]> > Cc: Jaegeuk Kim <[email protected]> > Cc: Chao Yu <[email protected]> > Cc: [email protected] > Cc: Christoph Hellwig <[email protected]> > Cc: [email protected] > Cc: Anton Altaparmakov <[email protected]> > Cc: [email protected] > Cc: Mike Marshall <[email protected]> > Cc: Martin Brandenburg <[email protected]> > Cc: [email protected] > Cc: Thomas Gleixner <[email protected]> > Cc: Sebastian Andrzej Siewior <[email protected]> > Cc: Roman Gushchin <[email protected]> > Cc: Andreas Dilger <[email protected]> > Signed-off-by: Guoqing Jiang <[email protected]> > --- > 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 _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
