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authorDavid Howells2021-08-12 22:09:57 +0100
committerDavid Howells2021-11-10 21:16:52 +0000
commit452c472e26348df1e7052544130aa98eebbd2331 (patch)
treee6fe630639ed2a00c862269c3f247e67022b58de
parenta19672f6b9718df247a9087a266150dbe833022e (diff)
folio: Add a function to get the host inode for a folio
Add a convenience function, folio_inode() that will get the host inode from a folio's mapping. Changes: ver #3: - Fix mistake in function description[2]. ver #2: - Fix contradiction between doc and implementation by disallowing use with swap caches[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Tested-by: Jeff Layton <jlayton@kernel.org> Tested-by: Dominique Martinet <asmadeus@codewreck.org> Tested-by: kafs-testing@auristor.com Link: https://lore.kernel.org/r/YST8OcVNy02Rivbm@casper.infradead.org/ [1] Link: https://lore.kernel.org/r/YYKLkBwQdtn4ja+i@casper.infradead.org/ [2] 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 Link: https://lore.kernel.org/r/163584184628.4023316.9386282630968981869.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/163649325519.309189.15072332908703129455.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/163657850401.834781.1031963517399283294.stgit@warthog.procyon.org.uk/ # v5
-rw-r--r--include/linux/pagemap.h14
-rw-r--r--mm/page-writeback.c2
2 files changed, 15 insertions, 1 deletions
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 1f560aecd9b5..1a0c646eb6ff 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -253,6 +253,20 @@ 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 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 2d498bb62248..a613f8ef6a02 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2967,7 +2967,7 @@ 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);