[PATCH] mm: move dummy_vm_ops out of a header

From: Mateusz Guzik
Date: Fri Aug 04 2023 - 21:41:16 EST


Otherwise the kernel ends up with multiple copies:
$ nm vmlinux | grep dummy_vm_ops
ffffffff81e4ea00 d dummy_vm_ops.2
ffffffff81e11760 d dummy_vm_ops.254
ffffffff81e406e0 d dummy_vm_ops.4
ffffffff81e3c780 d dummy_vm_ops.7

[if someone has better ideas where to put it, please move it]

Signed-off-by: Mateusz Guzik <mjguzik@xxxxxxxxx>
---
include/linux/mm.h | 6 +++---
mm/init-mm.c | 2 ++
2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 406ab9ea818f..14898e76bbf1 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -756,17 +756,17 @@ static inline void vma_mark_detached(struct vm_area_struct *vma,

#endif /* CONFIG_PER_VMA_LOCK */

+extern const struct vm_operations_struct vma_dummy_vm_ops;
+
/*
* WARNING: vma_init does not initialize vma->vm_lock.
* Use vm_area_alloc()/vm_area_free() if vma needs locking.
*/
static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm)
{
- static const struct vm_operations_struct dummy_vm_ops = {};
-
memset(vma, 0, sizeof(*vma));
vma->vm_mm = mm;
- vma->vm_ops = &dummy_vm_ops;
+ vma->vm_ops = &vma_dummy_vm_ops;
INIT_LIST_HEAD(&vma->anon_vma_chain);
vma_mark_detached(vma, false);
vma_numab_state_init(vma);
diff --git a/mm/init-mm.c b/mm/init-mm.c
index efa97b57acfd..cfd367822cdd 100644
--- a/mm/init-mm.c
+++ b/mm/init-mm.c
@@ -17,6 +17,8 @@
#define INIT_MM_CONTEXT(name)
#endif

+const struct vm_operations_struct vma_dummy_vm_ops;
+
/*
* For dynamically allocated mm_structs, there is a dynamically sized cpumask
* at the end of the structure, the size of which depends on the maximum CPU
--
2.39.2