| Message ID | 20230228213738.272178-4-willy@infradead.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | New page table range API | expand |
On Tue, Feb 28, 2023 at 09:37:06PM +0000, Matthew Wilcox (Oracle) wrote: > This is the folio equivalent of page_mapping_file(), but rename it > to make it clear that it's very different from page_file_mapping(). > Theoretically, there's nothing flush-only about it, but there are no > other users today, and I doubt there will be; it's almost always more > useful to know the swapfile's mapping or the swapcache's mapping. > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> > --- > include/linux/pagemap.h | 26 +++++++++++++++++++++----- > 1 file changed, 21 insertions(+), 5 deletions(-) > > diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h > index 51b75b89730e..1b1ba3d5100d 100644 > --- a/include/linux/pagemap.h > +++ b/include/linux/pagemap.h > @@ -369,6 +369,26 @@ static inline struct address_space *folio_file_mapping(struct folio *folio) > return folio->mapping; > } > > +/** > + * folio_flush_mapping - Find the file mapping this folio belongs to. > + * @folio: The folio. > + * > + * For folios which are in the page cache, return the mapping that this > + * page belongs to. Anonymous folios return NULL, even if they're in ^ folio ? > + * the swap cache. Other kinds of folio also return NULL. > + * > + * This is ONLY used by architecture cache flushing code. If you aren't > + * writing cache flushing code, you want either folio_mapping() or > + * folio_file_mapping(). > + */ > +static inline struct address_space *folio_flush_mapping(struct folio *folio) > +{ > + if (unlikely(folio_test_swapcache(folio))) > + return NULL; > + > + return folio_mapping(folio); > +} > + > static inline struct address_space *page_file_mapping(struct page *page) > { > return folio_file_mapping(page_folio(page)); > @@ -379,11 +399,7 @@ static inline struct address_space *page_file_mapping(struct page *page) > */ > static inline struct address_space *page_mapping_file(struct page *page) > { > - struct folio *folio = page_folio(page); > - > - if (unlikely(folio_test_swapcache(folio))) > - return NULL; > - return folio_mapping(folio); > + return folio_flush_mapping(page_folio(page)); > } > > /** > -- > 2.39.1 >
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 51b75b89730e..1b1ba3d5100d 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -369,6 +369,26 @@ static inline struct address_space *folio_file_mapping(struct folio *folio) return folio->mapping; } +/** + * folio_flush_mapping - Find the file mapping this folio belongs to. + * @folio: The folio. + * + * For folios which are in the page cache, return the mapping that this + * page belongs to. Anonymous folios return NULL, even if they're in + * the swap cache. Other kinds of folio also return NULL. + * + * This is ONLY used by architecture cache flushing code. If you aren't + * writing cache flushing code, you want either folio_mapping() or + * folio_file_mapping(). + */ +static inline struct address_space *folio_flush_mapping(struct folio *folio) +{ + if (unlikely(folio_test_swapcache(folio))) + return NULL; + + return folio_mapping(folio); +} + static inline struct address_space *page_file_mapping(struct page *page) { return folio_file_mapping(page_folio(page)); @@ -379,11 +399,7 @@ static inline struct address_space *page_file_mapping(struct page *page) */ static inline struct address_space *page_mapping_file(struct page *page) { - struct folio *folio = page_folio(page); - - if (unlikely(folio_test_swapcache(folio))) - return NULL; - return folio_mapping(folio); + return folio_flush_mapping(page_folio(page)); } /**
This is the folio equivalent of page_mapping_file(), but rename it to make it clear that it's very different from page_file_mapping(). Theoretically, there's nothing flush-only about it, but there are no other users today, and I doubt there will be; it's almost always more useful to know the swapfile's mapping or the swapcache's mapping. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> --- include/linux/pagemap.h | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-)