On Tue Nov 12, 2024 at 8:45 AM CET, 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>
> Reviewed-by: Barry Song <baohua@xxxxxxxxxx>
> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Daniel Gomez <da.gomez@xxxxxxxxxxx>
> ---
> 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);
