From: Taotao Chen <chentao...@didiglobal.com>
Add write_begin_get_folio() to simplify the common folio lookup logic
used by filesystem ->write_begin() implementations.
This helper wraps __filemap_get_folio() with common flags such as
FGP_WRITEBEGIN, conditional FGP_DONTCACHE, and set folio order based
on the write length.
Part of a series refactoring address_space_operations write_begin and
write_end callbacks to use struct kiocb for passing write context and
flags.
Signed-off-by: Taotao Chen <chentao...@didiglobal.com>
---
include/linux/pagemap.h | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index e63fbfbd5b0f..ce2bcdcadb73 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -750,6 +750,33 @@ struct folio *__filemap_get_folio(struct address_space
*mapping, pgoff_t index,
struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
fgf_t fgp_flags, gfp_t gfp);
+/**
+ * write_begin_get_folio - Get folio for write_begin with flags.
+ * @iocb: The kiocb passed from write_begin (may be NULL).
+ * @mapping: The address space to search.
+ * @index: The page cache index.
+ * @len: Length of data being written.
+ *
+ * This is a helper for filesystem write_begin() implementations.
+ * It wraps __filemap_get_folio(), setting appropriate flags in
+ * the write begin context.
+ *
+ * Return: A folio or an ERR_PTR.
+ */
+static inline struct folio *write_begin_get_folio(const struct kiocb *iocb,
+ struct address_space *mapping, pgoff_t index, size_t len)
+{
+ fgf_t fgp_flags = FGP_WRITEBEGIN;
+
+ fgp_flags |= fgf_set_order(len);
+
+ if (iocb && iocb->ki_flags & IOCB_DONTCACHE)
+ fgp_flags |= FGP_DONTCACHE;
+
+ return __filemap_get_folio(mapping, index, fgp_flags,
+ mapping_gfp_mask(mapping));
+}
+
/**
* filemap_get_folio - Find and get a folio.
* @mapping: The address_space to search.
--
2.34.1
