diff options
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/huge_mm.h | 18 | ||||
| -rw-r--r-- | include/linux/mm.h | 14 |
2 files changed, 12 insertions, 20 deletions
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 3935428c57cf..a291552ab767 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -156,23 +156,6 @@ static inline int hpage_nr_pages(struct page *page) return HPAGE_PMD_NR; return 1; } -static inline struct page *compound_trans_head(struct page *page) -{ - if (PageTail(page)) { - struct page *head; - head = page->first_page; - smp_rmb(); - /* - * head may be a dangling pointer. - * __split_huge_page_refcount clears PageTail before - * overwriting first_page, so if PageTail is still - * there it means the head pointer isn't dangling. - */ - if (PageTail(page)) - return head; - } - return page; -} extern int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, pmd_t pmd, pmd_t *pmdp); @@ -202,7 +185,6 @@ static inline int split_huge_page(struct page *page) do { } while (0) #define split_huge_page_pmd_mm(__mm, __address, __pmd) \ do { } while (0) -#define compound_trans_head(page) compound_head(page) static inline int hugepage_madvise(struct vm_area_struct *vma, unsigned long *vm_flags, int advice) { diff --git a/include/linux/mm.h b/include/linux/mm.h index 648bcb007eba..073734339583 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -371,8 +371,18 @@ static inline void compound_unlock_irqrestore(struct page *page, static inline struct page *compound_head(struct page *page) { - if (unlikely(PageTail(page))) - return page->first_page; + if (unlikely(PageTail(page))) { + struct page *head = page->first_page; + + /* + * page->first_page may be a dangling pointer to an old + * compound page, so recheck that it is still a tail + * page before returning. + */ + smp_rmb(); + if (likely(PageTail(page))) + return head; + } return page; } |