Messages in this thread | | | Subject | Re: [RFC PATCH V2 1/9] include/linux/pagemap.h: introduce attach/clear_page_private | From | Guoqing Jiang <> | Date | Fri, 1 May 2020 08:38:09 +0200 |
| |
On 5/1/20 12:10 AM, Andreas Grünbacher wrote: > 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?
Yes, the new name is better, thank you!
Cheers, Guoqing
| |