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mm/vma: introduce vmi_complete_munmap_vmas()

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Extract all necessary operations that need to be completed after the vma
maple tree is updated from a munmap() operation.  Extracting this makes
the later patch in the series easier to understand.

Link: https://lkml.kernel.org/r/20240830040101.822209-4-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Cc: Bert Karwatzki <spasswolf@web.de>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Liam R. Howlett 2024-08-30 00:00:43 -04:00 committed by Andrew Morton
parent 7e7b2370ed
commit 01cf21e9e1
1 changed files with 55 additions and 25 deletions
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80
mm/vma.c
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@ -684,6 +684,58 @@ static inline void abort_munmap_vmas(struct ma_state *mas_detach)
__mt_destroy(mas_detach->tree);
}
/*
* vmi_complete_munmap_vmas() - Finish the munmap() operation
* @vmi: The vma iterator
* @vma: The first vma to be munmapped
* @mm: The mm struct
* @start: The start address
* @end: The end address
* @unlock: Unlock the mm or not
* @mas_detach: them maple state of the detached vma maple tree
* @locked_vm: The locked_vm count in the detached vmas
*
* This function updates the mm_struct, unmaps the region, frees the resources
* used for the munmap() and may downgrade the lock - if requested. Everything
* needed to be done once the vma maple tree is updated.
*/
static void
vmi_complete_munmap_vmas(struct vma_iterator *vmi, struct vm_area_struct *vma,
struct mm_struct *mm, unsigned long start, unsigned long end,
bool unlock, struct ma_state *mas_detach,
unsigned long locked_vm)
{
struct vm_area_struct *prev, *next;
int count;
count = mas_detach->index + 1;
mm->map_count -= count;
mm->locked_vm -= locked_vm;
if (unlock)
mmap_write_downgrade(mm);
prev = vma_iter_prev_range(vmi);
next = vma_next(vmi);
if (next)
vma_iter_prev_range(vmi);
/*
* We can free page tables without write-locking mmap_lock because VMAs
* were isolated before we downgraded mmap_lock.
*/
mas_set(mas_detach, 1);
unmap_region(mm, mas_detach, vma, prev, next, start, end, count,
!unlock);
/* Statistics and freeing VMAs */
mas_set(mas_detach, 0);
remove_mt(mm, mas_detach);
validate_mm(mm);
if (unlock)
mmap_read_unlock(mm);
__mt_destroy(mas_detach->tree);
}
/*
* do_vmi_align_munmap() - munmap the aligned region from @start to @end.
* @vmi: The vma iterator
@ -703,7 +755,7 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
struct mm_struct *mm, unsigned long start,
unsigned long end, struct list_head *uf, bool unlock)
{
struct vm_area_struct *prev, *next = NULL;
struct vm_area_struct *next = NULL;
struct maple_tree mt_detach;
int count = 0;
int error = -ENOMEM;
@ -818,31 +870,9 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
goto clear_tree_failed;
/* Point of no return */
mm->locked_vm -= locked_vm;
mm->map_count -= count;
if (unlock)
mmap_write_downgrade(mm);
vmi_complete_munmap_vmas(vmi, vma, mm, start, end, unlock, &mas_detach,
locked_vm);
prev = vma_iter_prev_range(vmi);
next = vma_next(vmi);
if (next)
vma_iter_prev_range(vmi);
/*
* We can free page tables without write-locking mmap_lock because VMAs
* were isolated before we downgraded mmap_lock.
*/
mas_set(&mas_detach, 1);
unmap_region(mm, &mas_detach, vma, prev, next, start, end, count,
!unlock);
/* Statistics and freeing VMAs */
mas_set(&mas_detach, 0);
remove_mt(mm, &mas_detach);
validate_mm(mm);
if (unlock)
mmap_read_unlock(mm);
__mt_destroy(&mt_detach);
return 0;
modify_vma_failed: