[PATCH 03/17] mm: Add folio_end_read()

Matthew Wilcox (Oracle)
2023-09-15T18:38:18Z

Provide a function for filesystems to call when they have finished
reading an entire folio.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
include/linux/pagemap.h | 1 +
mm/filemap.c | 22 ++++++++++++++++++++++
2 files changed, 23 insertions(+)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 351c3b7f93a1..5bb2f5f802bc 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -1129,6 +1129,7 @@ static inline void wait_on_page_locked(struct page *page)
folio_wait_locked(page_folio(page));
}

+void folio_end_read(struct folio *folio, bool success);
void wait_on_page_writeback(struct page *page);
void folio_wait_writeback(struct folio *folio);
int folio_wait_writeback_killable(struct folio *folio);
diff --git a/mm/filemap.c b/mm/filemap.c
index 582f5317ff71..e3843cf1d8e1 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1527,6 +1527,28 @@ void folio_unlock(struct folio *folio)
}
EXPORT_SYMBOL(folio_unlock);

+/**
+ * folio_end_read - End read on a folio.
+ * @folio: The folio.
+ * @success: True if all reads completed successfully.
+ *
+ * When all reads against a folio have completed, filesystems should
+ * call this function to let the pagecache know that no more reads
+ * are outstanding. This will unlock the folio and wake up any thread
+ * sleeping on the lock. The folio will also be marked uptodate if all
+ * reads succeeded.
+ *
+ * Context: May be called from interrupt or process context. May not be
+ * called from NMI context.
+ */
+void folio_end_read(struct folio *folio, bool success)
+{
+ if (success)
+ folio_mark_uptodate(folio);
+ folio_unlock(folio);
+}
+EXPORT_SYMBOL(folio_end_read);
+
/**
* folio_end_private_2 - Clear PG_private_2 and wake any waiters.
* @folio: The folio.
--
2.40.1