* and just make the page writable */
avoidcopy = (page_mapcount(old_page) == 1);
if (avoidcopy) {
- if (!trylock_page(old_page)) {
- if (PageAnon(old_page))
- page_move_anon_rmap(old_page, vma, address);
- } else
- unlock_page(old_page);
+ if (PageAnon(old_page))
+ page_move_anon_rmap(old_page, vma, address);
set_huge_ptep_writable(vma, address, ptep);
return 0;
}
set_huge_pte_at(mm, address, ptep,
make_huge_pte(vma, new_page, 1));
page_remove_rmap(old_page);
- hugepage_add_anon_rmap(new_page, vma, address);
+ hugepage_add_new_anon_rmap(new_page, vma, address);
/* Make the old page be freed below */
new_page = old_page;
mmu_notifier_invalidate_range_end(mm,
hugepage_add_new_anon_rmap(page, vma, address);
}
} else {
+ /*
+ * If memory error occurs between mmap() and fault, some process
+ * don't have hwpoisoned swap entry for errored virtual address.
+ * So we need to block hugepage fault by PG_hwpoison bit check.
+ */
+ if (unlikely(PageHWPoison(page))) {
+ ret = VM_FAULT_HWPOISON;
+ goto backout_unlocked;
+ }
page_dup_rmap(page);
}
/*
- * Since memory error handler replaces pte into hwpoison swap entry
- * at the time of error handling, a process which reserved but not have
- * the mapping to the error hugepage does not have hwpoison swap entry.
- * So we need to block accesses from such a process by checking
- * PG_hwpoison bit here.
- */
- if (unlikely(PageHWPoison(page))) {
- ret = VM_FAULT_HWPOISON;
- goto backout_unlocked;
- }
-
- /*
* If we are going to COW a private mapping later, we examine the
* pending reservations for this page now. This will ensure that
* any allocations necessary to record that reservation occur outside
vma, address);
}
- if (!pagecache_page) {
- page = pte_page(entry);
+ /*
+ * hugetlb_cow() requires page locks of pte_page(entry) and
+ * pagecache_page, so here we need take the former one
+ * when page != pagecache_page or !pagecache_page.
+ * Note that locking order is always pagecache_page -> page,
+ * so no worry about deadlock.
+ */
+ page = pte_page(entry);
+ if (page != pagecache_page)
lock_page(page);
- }
spin_lock(&mm->page_table_lock);
/* Check for a racing update before calling hugetlb_cow */
if (pagecache_page) {
unlock_page(pagecache_page);
put_page(pagecache_page);
- } else {
- unlock_page(page);
}
+ unlock_page(page);
out_mutex:
mutex_unlock(&hugetlb_instantiation_mutex);