On Tue, Sep 9, 2025 at 12:10 PM Liam R. Howlett <Liam.Howlett@oracle.com> wrote:
>
> The unmap_region() calls need to pass through the page table limit for a
> future patch.
>
> No functional changes intended.
>
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
> ---
> mm/vma.c | 5 +++--
> mm/vma.h | 2 +-
> 2 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/mm/vma.c b/mm/vma.c
> index 1bae142bbc0f1..4c850ffd83a4b 100644
> --- a/mm/vma.c
> +++ b/mm/vma.c
> @@ -474,7 +474,7 @@ void remove_vma(struct vm_area_struct *vma)
> * Called with the mm semaphore held.
> */
> void unmap_region(struct ma_state *mas, struct vm_area_struct *vma,
> - unsigned long vma_min, unsigned long vma_max,
> + unsigned long vma_min, unsigned long vma_max, unsigned long pg_max,
> struct vm_area_struct *prev, struct vm_area_struct *next)
> {
> struct mm_struct *mm = vma->vm_mm;
> @@ -487,7 +487,7 @@ void unmap_region(struct ma_state *mas, struct vm_area_struct *vma,
> mas_set(mas, vma->vm_end);
> free_pgtables(&tlb, mas, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS,
> next ? next->vm_start : USER_PGTABLES_CEILING,
> - next ? next->vm_start : USER_PGTABLES_CEILING,
> + pg_max,
Hmm. The free_pgtables() parameters were advertised as:
@floor: The lowest page table address
@ceiling: The highest page table address
@tree_max: The highest tree search address
but here tree_max=pg_max. I would expect pg_max to mean "The highest
page table address", IOW we should have ceiling=pg_max. Either the
order of the parameters is wrong here or the names are misleading.
I also think in the previous patch we should have renamed
free_pgtables() parameters to vma_min, vma_max and pg_max like here
for consistency and to avoid confusion.
> /* mm_wr_locked = */ true);
> tlb_finish_mmu(&tlb);
> }
> @@ -2420,6 +2420,7 @@ static int __mmap_new_file_vma(struct mmap_state *map,
> vma_iter_set(vmi, vma->vm_end);
> /* Undo any partial mapping done by a device driver. */
> unmap_region(&vmi->mas, vma, vma->vm_start, vma->vm_end,
> + map->next ? map->next->vm_start : USER_PGTABLES_CEILING,
> map->prev, map->next);
>
> return error;
> diff --git a/mm/vma.h b/mm/vma.h
> index a9d0cef684ddb..b0ebc81d5862e 100644
> --- a/mm/vma.h
> +++ b/mm/vma.h
> @@ -261,7 +261,7 @@ int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm,
> void remove_vma(struct vm_area_struct *vma);
>
> void unmap_region(struct ma_state *mas, struct vm_area_struct *vma,
> - unsigned long min, unsigned long max,
> + unsigned long min, unsigned long max, unsigned long pg_max,
> struct vm_area_struct *prev, struct vm_area_struct *next);
>
> /* We are about to modify the VMA's flags. */
> --
> 2.47.2
>