Commit 01cf21e9 authored by Liam R. Howlett's avatar Liam R. Howlett Committed by Andrew Morton
Browse files

mm/vma: introduce vmi_complete_munmap_vmas() 

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: default avatarLiam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: default avatarLorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: default avatarSuren 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: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 7e7b2370

mm/vma.c

+55 −25
Original line number Diff line number Diff line
@@ -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);



	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);

	vmi_complete_munmap_vmas(vmi, vma, mm, start, end, unlock, &mas_detach,

				 locked_vm);



	__mt_destroy(&mt_detach);

	return 0;



modify_vma_failed: