Factor out the order calculation into a new helper, which can be reused
by shmem in the following patch.
Suggested-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
---
include/linux/pagemap.h | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index bcf0865a38ae..d796c8a33647 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -727,6 +727,16 @@ typedef unsigned int __bitwise fgf_t;
#define FGP_WRITEBEGIN (FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE)
+static inline unsigned int filemap_get_order(size_t size)
+{
+ unsigned int shift = ilog2(size);
+
+ if (shift <= PAGE_SHIFT)
+ return 0;
+
+ return shift - PAGE_SHIFT;
+}
+
/**
* fgf_set_order - Encode a length in the fgf_t flags.
* @size: The suggested size of the folio to create.
@@ -740,11 +750,11 @@ typedef unsigned int __bitwise fgf_t;
*/
static inline fgf_t fgf_set_order(size_t size)
{
- unsigned int shift = ilog2(size);
+ unsigned int order = filemap_get_order(size);
- if (shift <= PAGE_SHIFT)
+ if (!order)
return 0;
- return (__force fgf_t)((shift - PAGE_SHIFT) << 26);
+ return (__force fgf_t)(order << 26);
}
void *filemap_get_entry(struct address_space *mapping, pgoff_t index);
--
2.39.3
