| Message ID | 163584184628.4023316.9386282630968981869.stgit@warthog.procyon.org.uk |
|---|---|
| State | New |
| Headers | show |
| Series | netfs, 9p, afs, ceph: Support folios, at least partially | expand |
On Tue, Nov 02, 2021 at 08:30:46AM +0000, David Howells wrote: > Add a convenience function, folio_inode() that will get the host inode from > a folio's mapping. I'm not opposed, but it only saves two characters, so I'm not entirely sure it justifies its existance. On the other hand, folio_inode() is clear about what it does. > + * For folios which are in the page cache, return the inode that is hosting > + * this folio belongs to. This looks like an editing mistake. Either you meant 'return the inode that hosts this folio' or 'return the inode this folio belongs to' (and i prefer the second). With that grammo fixed, Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Matthew Wilcox <willy@infradead.org> wrote: > > + * For folios which are in the page cache, return the inode that is hosting > > + * this folio belongs to. > > This looks like an editing mistake. Either you meant > 'return the inode that hosts this folio' or > 'return the inode this folio belongs to' > (and i prefer the second). Yeah - I'll go with that. David
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 569302e4defe..fc4b7fcf4cc5 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -203,6 +203,20 @@ static inline struct address_space *page_mapping_file(struct page *page) return folio_mapping(folio); } +/** + * folio_inode - Get the host inode for this folio. + * @folio: The folio. + * + * For folios which are in the page cache, return the inode that is hosting + * this folio belongs to. + * + * Do not call this for folios which aren't in the page cache. + */ +static inline struct inode *folio_inode(struct folio *folio) +{ + return folio->mapping->host; +} + static inline bool page_cache_add_speculative(struct page *page, int count) { VM_BUG_ON_PAGE(PageTail(page), page); diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 9c64490171e0..c4d2414a92dd 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2960,7 +2960,7 @@ EXPORT_SYMBOL_GPL(folio_wait_writeback_killable); */ void folio_wait_stable(struct folio *folio) { - if (folio->mapping->host->i_sb->s_iflags & SB_I_STABLE_WRITES) + if (folio_inode(folio)->i_sb->s_iflags & SB_I_STABLE_WRITES) folio_wait_writeback(folio); } EXPORT_SYMBOL_GPL(folio_wait_stable);
Add a convenience function, folio_inode() that will get the host inode from a folio's mapping. Changes: ver #2: - Fix contradiction between doc and implementation by disallowing use with swap caches[1]. Signed-off-by: David Howells <dhowells@redhat.com> Link: https://lore.kernel.org/r/YST8OcVNy02Rivbm@casper.infradead.org/ [1] Link: https://lore.kernel.org/r/162880453171.3369675.3704943108660112470.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/162981151155.1901565.7010079316994382707.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/163005744370.2472992.18324470937328925723.stgit@warthog.procyon.org.uk/ # v2 --- include/linux/pagemap.h | 14 ++++++++++++++ mm/page-writeback.c | 2 +- 2 files changed, 15 insertions(+), 1 deletion(-)