[PATCH 1/8] mm: add rest_of_page() macro

Yury Norov
2026-03-04T01:27:29Z

The net/9p networking driver has a handy macro to calculate the
amount of bytes from a given pointer to the end of page. Move it
to mm. The following patches apply it tree-wide.

Signed-off-by: Yury Norov <ynorov@nvidia.com>
---
include/linux/mm.h | 2 ++
net/9p/trans_virtio.c | 6 ------
2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5be3d8a8f806..6d1025c6249a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2793,6 +2793,8 @@ extern void pagefault_out_of_memory(void);
#define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK)
#define offset_in_folio(folio, p) ((unsigned long)(p) & (folio_size(folio) - 1))

+#define rest_of_page(p) (PAGE_SIZE - offset_in_page(p))
+
/*
* Parameter block passed down to zap_pte_range in exceptional cases.
*/
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 4cdab7094b27..1ca53209d036 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -87,12 +87,6 @@ struct virtio_chan {

static struct list_head virtio_chan_list;

-/* How many bytes left in this page. */
-static unsigned int rest_of_page(void *data)
-{
- return PAGE_SIZE - offset_in_page(data);
-}
-
/**
* p9_virtio_close - reclaim resources of a channel
* @client: client instance
--
2.43.0