[PATCH 3/6] folio: Add a function to get the host inode for a folio
From: David Howells <dhowells@redhat.com>
Date: 2021-08-24 13:25:24
Also in:
ceph-devel, linux-cifs, linux-fsdevel, linux-mm, lkml
Subsystem:
memory management, page cache, the rest · Maintainers:
Andrew Morton, Matthew Wilcox, Linus Torvalds
Add a convenience function, folio_inode() that will get the host inode from a folio's mapping. Signed-off-by: David Howells <dhowells@redhat.com> --- include/linux/pagemap.h | 14 ++++++++++++++ mm/page-writeback.c | 2 +- 2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index c8d336e62177..115b4f831e7d 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_file_mapping(folio)->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 86b90173baf8..f750946d11f7 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c@@ -2918,7 +2918,7 @@ 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);