On 08.11.24 05:12, Baolin Wang wrote:
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;
+}
+
I'd have added some words somewhere, how this differs to get_order()
[calculated order might not have space to fit the complete size] and why
[avoid over-allocation].
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
--
Cheers,
David / dhildenb
