[PATCH 1/2] mm/vma: add vma_is_*_locked() helpers
From: Lorenzo Stoakes <hidden>
Date: 2026-01-16 10:28:38
Also in:
lkml
Subsystem:
memory mapping - locking, the rest · Maintainers:
Andrew Morton, Suren Baghdasaryan, Liam R. Howlett, Lorenzo Stoakes, Linus Torvalds
Add vma_is_read_locked(), vma_is_write_locked() and vma_is_locked() helpers and utilise them in vma_assert_locked() and vma_assert_write_locked(). These functions will intentionally not be defined if CONFIG_PER_VMA_LOCK is not set, as they would not make any sense in a context where VMA locks do not exist. This lays the groundwork for a subsequent change that allows for asserting that either the mmap lock or VMA lock is held. Suggested-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Lorenzo Stoakes <redacted> --- include/linux/mmap_lock.h | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-)
diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h
index b50416fbba20..cd51e0a43c76 100644
--- a/include/linux/mmap_lock.h
+++ b/include/linux/mmap_lock.h@@ -236,19 +236,31 @@ int vma_start_write_killable(struct vm_area_struct *vma) return __vma_start_write(vma, mm_lock_seq, TASK_KILLABLE); } -static inline void vma_assert_write_locked(struct vm_area_struct *vma) +static inline bool vma_is_read_locked(struct vm_area_struct *vma) +{ + return refcount_read(&vma->vm_refcnt) > 1; +} + +static inline bool vma_is_write_locked(struct vm_area_struct *vma) { unsigned int mm_lock_seq; - VM_BUG_ON_VMA(!__is_vma_write_locked(vma, &mm_lock_seq), vma); + return __is_vma_write_locked(vma, &mm_lock_seq); } -static inline void vma_assert_locked(struct vm_area_struct *vma) +static inline bool vma_is_locked(struct vm_area_struct *vma) { - unsigned int mm_lock_seq; + return vma_is_read_locked(vma) || vma_is_write_locked(vma); +} - VM_BUG_ON_VMA(refcount_read(&vma->vm_refcnt) <= 1 && - !__is_vma_write_locked(vma, &mm_lock_seq), vma); +static inline void vma_assert_write_locked(struct vm_area_struct *vma) +{ + VM_BUG_ON_VMA(!vma_is_write_locked(vma), vma); +} + +static inline void vma_assert_locked(struct vm_area_struct *vma) +{ + VM_BUG_ON_VMA(!vma_is_locked(vma), vma); } static inline bool vma_is_attached(struct vm_area_struct *vma)
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2.52.0