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kernel/fork: convert forking to using the vmi iterator 

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

Link: https://lkml.kernel.org/r/20230120162650.984577-10-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Liam R. Howlett 2023-01-20 11:26:10 -05:00 committed by Andrew Morton
parent 92fed82047
commit 3b9dbd5e91
1 changed files with 8 additions and 11 deletions
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19
kernel/fork.c
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@ -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 @@ fail_uprobe_end:
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));