* Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx> [240823 16:07]:
> The purpose of the vmg is to thread merge state through functions and avoid
> egregious parameter lists. We expand this to vma_expand(), which is used
> for a number of merge cases.
>
> Accordingly, adjust its callers, mmap_region() and relocate_vma_down(), to
> use a vmg.
>
> An added purpose of this change is the ability in a future commit to
> perform all new VMA range merging using vma_expand().
>
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Just one extra whitespace below.
Reviewed-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
> ---
> mm/mmap.c | 16 +++++++++-------
> mm/vma.c | 39 +++++++++++++++++----------------------
> mm/vma.h | 5 +----
> tools/testing/vma/vma.c | 3 +--
> 4 files changed, 28 insertions(+), 35 deletions(-)
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index c72f50feb98a..0d242c9b1f4c 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -1371,7 +1371,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> struct ma_state mas_detach;
> struct maple_tree mt_detach;
> unsigned long end = addr + len;
> - unsigned long merge_start = addr, merge_end = end;
> bool writable_file_mapping = false;
> int error = -ENOMEM;
> VMA_ITERATOR(vmi, mm, addr);
> @@ -1424,8 +1423,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> /* Attempt to expand an old mapping */
> /* Check next */
> if (next && next->vm_start == end && can_vma_merge_before(&vmg)) {
> - merge_end = next->vm_end;
> - vma = next;
> + vmg.end = next->vm_end;
> + vma = vmg.vma = next;
> vmg.pgoff = next->vm_pgoff - pglen;
> /*
> * We set this here so if we will merge with the previous VMA in
> @@ -1438,15 +1437,15 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
>
> /* Check prev */
> if (prev && prev->vm_end == addr && can_vma_merge_after(&vmg)) {
> - merge_start = prev->vm_start;
> - vma = prev;
> + vmg.start = prev->vm_start;
> + vma = vmg.vma = prev;
> vmg.pgoff = prev->vm_pgoff;
> vma_prev(&vmi); /* Equivalent to going to the previous range */
> }
>
> if (vma) {
> /* Actually expand, if possible */
> - if (!vma_expand(&vmi, vma, merge_start, merge_end, vmg.pgoff, next)) {
> + if (!vma_expand(&vmg)) {
> khugepaged_enter_vma(vma, vm_flags);
> goto expanded;
> }
> @@ -2319,6 +2318,7 @@ int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift)
> unsigned long new_start = old_start - shift;
> unsigned long new_end = old_end - shift;
> VMA_ITERATOR(vmi, mm, new_start);
> + VMG_STATE(vmg, mm, &vmi, new_start, old_end, 0, vma->vm_pgoff);
> struct vm_area_struct *next;
> struct mmu_gather tlb;
>
> @@ -2335,7 +2335,8 @@ int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift)
> /*
> * cover the whole range: [new_start, old_end)
> */
> - if (vma_expand(&vmi, vma, new_start, old_end, vma->vm_pgoff, NULL))
> + vmg.vma = vma;
> + if (vma_expand(&vmg))
> return -ENOMEM;
>
> /*
> @@ -2368,6 +2369,7 @@ int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift)
> tlb_finish_mmu(&tlb);
>
> vma_prev(&vmi);
> +
Unnecessary whitespace change.
> /* Shrink the vma to just the new range */
> return vma_shrink(&vmi, vma, new_start, new_end, vma->vm_pgoff);
> }
> diff --git a/mm/vma.c b/mm/vma.c
> index b1ec412fac7f..4867ae722a9a 100644
> --- a/mm/vma.c
> +++ b/mm/vma.c
> @@ -467,30 +467,25 @@ void validate_mm(struct mm_struct *mm)
> /*
> * vma_expand - Expand an existing VMA
> *
> - * @vmi: The vma iterator
> - * @vma: The vma to expand
> - * @start: The start of the vma
> - * @end: The exclusive end of the vma
> - * @pgoff: The page offset of vma
> - * @next: The current of next vma.
> + * @vmg: Describes a VMA expansion operation.
> *
> - * Expand @vma to @start and @end. Can expand off the start and end. Will
> - * expand over @next if it's different from @vma and @end == @next->vm_end.
> - * Checking if the @vma can expand and merge with @next needs to be handled by
> - * the caller.
> + * Expand @vma to vmg->start and vmg->end. Can expand off the start and end.
> + * Will expand over vmg->next if it's different from vmg->vma and vmg->end ==
> + * vmg->next->vm_end. Checking if the vmg->vma can expand and merge with
> + * vmg->next needs to be handled by the caller.
> *
> * Returns: 0 on success
> */
> -int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
> - unsigned long start, unsigned long end, pgoff_t pgoff,
> - struct vm_area_struct *next)
> +int vma_expand(struct vma_merge_struct *vmg)
> {
> struct vm_area_struct *anon_dup = NULL;
> bool remove_next = false;
> + struct vm_area_struct *vma = vmg->vma;
> + struct vm_area_struct *next = vmg->next;
> struct vma_prepare vp;
>
> vma_start_write(vma);
> - if (next && (vma != next) && (end == next->vm_end)) {
> + if (next && (vma != next) && (vmg->end == next->vm_end)) {
> int ret;
>
> remove_next = true;
> @@ -503,21 +498,21 @@ int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
> init_multi_vma_prep(&vp, vma, NULL, remove_next ? next : NULL, NULL);
> /* Not merging but overwriting any part of next is not handled. */
> VM_WARN_ON(next && !vp.remove &&
> - next != vma && end > next->vm_start);
> + next != vma && vmg->end > next->vm_start);
> /* Only handles expanding */
> - VM_WARN_ON(vma->vm_start < start || vma->vm_end > end);
> + VM_WARN_ON(vma->vm_start < vmg->start || vma->vm_end > vmg->end);
>
> /* Note: vma iterator must be pointing to 'start' */
> - vma_iter_config(vmi, start, end);
> - if (vma_iter_prealloc(vmi, vma))
> + vma_iter_config(vmg->vmi, vmg->start, vmg->end);
> + if (vma_iter_prealloc(vmg->vmi, vma))
> goto nomem;
>
> vma_prepare(&vp);
> - vma_adjust_trans_huge(vma, start, end, 0);
> - vma_set_range(vma, start, end, pgoff);
> - vma_iter_store(vmi, vma);
> + vma_adjust_trans_huge(vma, vmg->start, vmg->end, 0);
> + vma_set_range(vma, vmg->start, vmg->end, vmg->pgoff);
> + vma_iter_store(vmg->vmi, vma);
>
> - vma_complete(&vp, vmi, vma->vm_mm);
> + vma_complete(&vp, vmg->vmi, vma->vm_mm);
> return 0;
>
> nomem:
> diff --git a/mm/vma.h b/mm/vma.h
> index 9060a1a1edfa..8f01fbc20fe7 100644
> --- a/mm/vma.h
> +++ b/mm/vma.h
> @@ -128,10 +128,7 @@ void init_vma_prep(struct vma_prepare *vp,
> void vma_complete(struct vma_prepare *vp,
> struct vma_iterator *vmi, struct mm_struct *mm);
>
> -int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
> - unsigned long start, unsigned long end, pgoff_t pgoff,
> - struct vm_area_struct *next);
> -
> +int vma_expand(struct vma_merge_struct *vmg);
> int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,
> unsigned long start, unsigned long end, pgoff_t pgoff);
>
> diff --git a/tools/testing/vma/vma.c b/tools/testing/vma/vma.c
> index b12f72979478..cce1ba78c57f 100644
> --- a/tools/testing/vma/vma.c
> +++ b/tools/testing/vma/vma.c
> @@ -121,8 +121,7 @@ static struct vm_area_struct *merge_existing(struct vma_merge_struct *vmg)
> */
> static int expand_existing(struct vma_merge_struct *vmg)
> {
> - return vma_expand(vmg->vmi, vmg->vma, vmg->start, vmg->end, vmg->pgoff,
> - vmg->next);
> + return vma_expand(vmg);
> }
>
> /*
> --
> 2.46.0
>
