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https://github.com/torvalds/linux
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userfaultfd: use vma iterator
Use the vma iterator so that the iterator can be invalidated or updated to avoid each caller doing so. Link: https://lkml.kernel.org/r/20230120162650.984577-17-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
Andrew Morton
parent
27b2670112
commit
11a9b90274
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@ -883,7 +883,7 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
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/* len == 0 means wake all */
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struct userfaultfd_wake_range range = { .len = 0, };
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unsigned long new_flags;
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MA_STATE(mas, &mm->mm_mt, 0, 0);
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VMA_ITERATOR(vmi, mm, 0);
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WRITE_ONCE(ctx->released, true);
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@ -900,7 +900,7 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
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*/
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mmap_write_lock(mm);
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prev = NULL;
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mas_for_each(&mas, vma, ULONG_MAX) {
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for_each_vma(vmi, vma) {
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cond_resched();
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BUG_ON(!!vma->vm_userfaultfd_ctx.ctx ^
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!!(vma->vm_flags & __VM_UFFD_FLAGS));
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@ -909,13 +909,12 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
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continue;
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}
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new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS;
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prev = vma_merge(mm, prev, vma->vm_start, vma->vm_end,
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prev = vmi_vma_merge(&vmi, mm, prev, vma->vm_start, vma->vm_end,
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new_flags, vma->anon_vma,
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vma->vm_file, vma->vm_pgoff,
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vma_policy(vma),
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NULL_VM_UFFD_CTX, anon_vma_name(vma));
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if (prev) {
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mas_pause(&mas);
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vma = prev;
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} else {
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prev = vma;
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@ -1302,7 +1301,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
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bool found;
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bool basic_ioctls;
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unsigned long start, end, vma_end;
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MA_STATE(mas, &mm->mm_mt, 0, 0);
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struct vma_iterator vmi;
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user_uffdio_register = (struct uffdio_register __user *) arg;
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@ -1344,15 +1343,11 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
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if (!mmget_not_zero(mm))
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goto out;
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mmap_write_lock(mm);
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mas_set(&mas, start);
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vma = mas_find(&mas, ULONG_MAX);
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if (!vma)
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goto out_unlock;
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/* check that there's at least one vma in the range */
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ret = -EINVAL;
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if (vma->vm_start >= end)
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mmap_write_lock(mm);
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vma_iter_init(&vmi, mm, start);
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vma = vma_find(&vmi, end);
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if (!vma)
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goto out_unlock;
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/*
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@ -1371,7 +1366,8 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
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*/
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found = false;
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basic_ioctls = false;
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for (cur = vma; cur; cur = mas_next(&mas, end - 1)) {
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cur = vma;
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do {
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cond_resched();
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BUG_ON(!!cur->vm_userfaultfd_ctx.ctx ^
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@ -1428,16 +1424,14 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
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basic_ioctls = true;
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found = true;
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}
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} for_each_vma_range(vmi, cur, end);
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BUG_ON(!found);
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mas_set(&mas, start);
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prev = mas_prev(&mas, 0);
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if (prev != vma)
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mas_next(&mas, ULONG_MAX);
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vma_iter_set(&vmi, start);
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prev = vma_prev(&vmi);
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ret = 0;
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do {
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for_each_vma_range(vmi, vma, end) {
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cond_resched();
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BUG_ON(!vma_can_userfault(vma, vm_flags));
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@ -1458,30 +1452,25 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
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vma_end = min(end, vma->vm_end);
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new_flags = (vma->vm_flags & ~__VM_UFFD_FLAGS) | vm_flags;
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prev = vma_merge(mm, prev, start, vma_end, new_flags,
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prev = vmi_vma_merge(&vmi, mm, prev, start, vma_end, new_flags,
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vma->anon_vma, vma->vm_file, vma->vm_pgoff,
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vma_policy(vma),
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((struct vm_userfaultfd_ctx){ ctx }),
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anon_vma_name(vma));
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if (prev) {
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/* vma_merge() invalidated the mas */
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mas_pause(&mas);
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vma = prev;
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goto next;
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}
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if (vma->vm_start < start) {
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ret = split_vma(mm, vma, start, 1);
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ret = vmi_split_vma(&vmi, mm, vma, start, 1);
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if (ret)
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break;
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/* split_vma() invalidated the mas */
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mas_pause(&mas);
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}
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if (vma->vm_end > end) {
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ret = split_vma(mm, vma, end, 0);
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ret = vmi_split_vma(&vmi, mm, vma, end, 0);
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if (ret)
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break;
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/* split_vma() invalidated the mas */
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mas_pause(&mas);
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}
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next:
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/*
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@ -1498,8 +1487,8 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
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skip:
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prev = vma;
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start = vma->vm_end;
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vma = mas_next(&mas, end - 1);
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} while (vma);
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}
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out_unlock:
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mmap_write_unlock(mm);
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mmput(mm);
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@ -1543,7 +1532,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
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bool found;
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unsigned long start, end, vma_end;
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const void __user *buf = (void __user *)arg;
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MA_STATE(mas, &mm->mm_mt, 0, 0);
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struct vma_iterator vmi;
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ret = -EFAULT;
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if (copy_from_user(&uffdio_unregister, buf, sizeof(uffdio_unregister)))
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@ -1562,14 +1551,10 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
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goto out;
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mmap_write_lock(mm);
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mas_set(&mas, start);
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vma = mas_find(&mas, ULONG_MAX);
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if (!vma)
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goto out_unlock;
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/* check that there's at least one vma in the range */
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ret = -EINVAL;
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if (vma->vm_start >= end)
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vma_iter_init(&vmi, mm, start);
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vma = vma_find(&vmi, end);
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if (!vma)
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goto out_unlock;
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/*
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@ -1587,8 +1572,8 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
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* Search for not compatible vmas.
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*/
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found = false;
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ret = -EINVAL;
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for (cur = vma; cur; cur = mas_next(&mas, end - 1)) {
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cur = vma;
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do {
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cond_resched();
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BUG_ON(!!cur->vm_userfaultfd_ctx.ctx ^
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@ -1605,16 +1590,13 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
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goto out_unlock;
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found = true;
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}
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} for_each_vma_range(vmi, cur, end);
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BUG_ON(!found);
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mas_set(&mas, start);
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prev = mas_prev(&mas, 0);
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if (prev != vma)
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mas_next(&mas, ULONG_MAX);
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vma_iter_set(&vmi, start);
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prev = vma_prev(&vmi);
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ret = 0;
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do {
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for_each_vma_range(vmi, vma, end) {
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cond_resched();
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BUG_ON(!vma_can_userfault(vma, vma->vm_flags));
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@ -1650,26 +1632,23 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
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uffd_wp_range(mm, vma, start, vma_end - start, false);
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new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS;
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prev = vma_merge(mm, prev, start, vma_end, new_flags,
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prev = vmi_vma_merge(&vmi, mm, prev, start, vma_end, new_flags,
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vma->anon_vma, vma->vm_file, vma->vm_pgoff,
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vma_policy(vma),
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NULL_VM_UFFD_CTX, anon_vma_name(vma));
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if (prev) {
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vma = prev;
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mas_pause(&mas);
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goto next;
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}
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if (vma->vm_start < start) {
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ret = split_vma(mm, vma, start, 1);
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ret = vmi_split_vma(&vmi, mm, vma, start, 1);
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if (ret)
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break;
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mas_pause(&mas);
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}
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if (vma->vm_end > end) {
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ret = split_vma(mm, vma, end, 0);
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ret = vmi_split_vma(&vmi, mm, vma, end, 0);
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if (ret)
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break;
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mas_pause(&mas);
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}
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next:
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/*
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@ -1683,8 +1662,8 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
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skip:
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prev = vma;
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start = vma->vm_end;
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vma = mas_next(&mas, end - 1);
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} while (vma);
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}
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out_unlock:
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mmap_write_unlock(mm);
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mmput(mm);
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