if (page && arch_prepare_hugepage(page)) {
__free_pages(page, huge_page_order(h));
- return NULL;
+ page = NULL;
}
spin_lock(&hugetlb_lock);
* from page cache lookup which is in HPAGE_SIZE units.
*/
address = address & huge_page_mask(h);
- pgoff = ((address - vma->vm_start) >> PAGE_SHIFT)
- + (vma->vm_pgoff >> PAGE_SHIFT);
+ pgoff = vma_hugecache_offset(h, vma, address);
mapping = (struct address_space *)page_private(page);
/*
/*
* Hugetlb_cow() should be called with page lock of the original hugepage held.
+ * Called with hugetlb_instantiation_mutex held and pte_page locked so we
+ * cannot race with other handlers or page migration.
+ * Keep the pte_same checks anyway to make transition from the mutex easier.
*/
static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *ptep, pte_t pte,
BUG_ON(page_count(old_page) != 1);
BUG_ON(huge_pte_none(pte));
spin_lock(&mm->page_table_lock);
- goto retry_avoidcopy;
+ ptep = huge_pte_offset(mm, address & huge_page_mask(h));
+ if (likely(pte_same(huge_ptep_get(ptep), pte)))
+ goto retry_avoidcopy;
+ /*
+ * race occurs while re-acquiring page_table_lock, and
+ * our job is done.
+ */
+ return 0;
}
WARN_ON_ONCE(1);
}
static DEFINE_MUTEX(hugetlb_instantiation_mutex);
struct hstate *h = hstate_vma(vma);
+ address &= huge_page_mask(h);
+
ptep = huge_pte_offset(mm, address);
if (ptep) {
entry = huge_ptep_get(ptep);