[PATCH v3 09/48] kernel/fork: Convert forking to using the vmi iterator

Liam Howlett
2023-01-17T02:34:58Z

Avoid using the maple tree interface directly. This gains type safety.

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---
kernel/fork.c | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index 9f7fe3541897..441dcec60aae 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -585,8 +585,8 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
int retval;
unsigned long charge = 0;
LIST_HEAD(uf);
- MA_STATE(old_mas, &oldmm->mm_mt, 0, 0);
- MA_STATE(mas, &mm->mm_mt, 0, 0);
+ VMA_ITERATOR(old_vmi, oldmm, 0);
+ VMA_ITERATOR(vmi, mm, 0);

uprobe_start_dup_mmap();
if (mmap_write_lock_killable(oldmm)) {
@@ -613,11 +613,11 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
goto out;
khugepaged_fork(mm, oldmm);

- retval = mas_expected_entries(&mas, oldmm->map_count);
+ retval = vma_iter_bulk_alloc(&vmi, oldmm->map_count);
if (retval)
goto out;

- mas_for_each(&old_mas, mpnt, ULONG_MAX) {
+ for_each_vma(old_vmi, mpnt) {
struct file *file;

if (mpnt->vm_flags & VM_DONTCOPY) {
@@ -683,11 +683,8 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
hugetlb_dup_vma_private(tmp);

/* Link the vma into the MT */
- mas.index = tmp->vm_start;
- mas.last = tmp->vm_end - 1;
- mas_store(&mas, tmp);
- if (mas_is_err(&mas))
- goto fail_nomem_mas_store;
+ if (vma_iter_bulk_store(&vmi, tmp))
+ goto fail_nomem_vmi_store;

mm->map_count++;
if (!(tmp->vm_flags & VM_WIPEONFORK))
@@ -702,7 +699,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
/* a new mm has just been created */
retval = arch_dup_mmap(oldmm, mm);
loop_out:
- mas_destroy(&mas);
+ vma_iter_free(&vmi);
out:
mmap_write_unlock(mm);
flush_tlb_mm(oldmm);
@@ -712,7 +709,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
uprobe_end_dup_mmap();
return retval;

-fail_nomem_mas_store:
+fail_nomem_vmi_store:
unlink_anon_vmas(tmp);
fail_nomem_anon_vma_fork:
mpol_put(vma_policy(tmp));
--
2.35.1