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-rw-r--r--mm/hugetlb.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 55e6796b24d0..6a3cf7935c14 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1250,7 +1250,7 @@ void hugetlb_dup_vma_private(struct vm_area_struct *vma)
/*
* Reset and decrement one ref on hugepage private reservation.
* Called with mm->mmap_lock writer semaphore held.
- * This function should be only used by move_vma() and operate on
+ * This function should be only used by mremap and operate on
* same sized vma. It should never come here with last ref on the
* reservation.
*/
@@ -7939,3 +7939,17 @@ void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)
hugetlb_unshare_pmds(vma, ALIGN(vma->vm_start, PUD_SIZE),
ALIGN_DOWN(vma->vm_end, PUD_SIZE));
}
+
+/*
+ * For hugetlb, mremap() is an odd edge case - while the VMA copying is
+ * performed, we permit both the old and new VMAs to reference the same
+ * reservation.
+ *
+ * We fix this up after the operation succeeds, or if a newly allocated VMA
+ * is closed as a result of a failure to allocate memory.
+ */
+void fixup_hugetlb_reservations(struct vm_area_struct *vma)
+{
+ if (is_vm_hugetlb_page(vma))
+ clear_vma_resv_huge_pages(vma);
+}