diff options
| -rw-r--r-- | drivers/block/aoe/aoecmd.c | 2 | ||||
| -rw-r--r-- | drivers/vfio/vfio_iommu_type1.c | 4 | ||||
| -rw-r--r-- | fs/proc/page.c | 2 | ||||
| -rw-r--r-- | include/linux/huge_mm.h | 18 | ||||
| -rw-r--r-- | include/linux/mm.h | 14 | ||||
| -rw-r--r-- | mm/ksm.c | 2 | ||||
| -rw-r--r-- | mm/memory-failure.c | 2 | ||||
| -rw-r--r-- | mm/page_alloc.c | 4 | ||||
| -rw-r--r-- | mm/swap.c | 4 | ||||
| -rw-r--r-- | virt/kvm/kvm_main.c | 4 |
10 files changed, 25 insertions, 31 deletions
diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c index fc803ecbbce4..31262732db23 100644 --- a/drivers/block/aoe/aoecmd.c +++ b/drivers/block/aoe/aoecmd.c @@ -899,7 +899,7 @@ bio_pageinc(struct bio *bio) * but this has never been seen here. */ if (unlikely(PageCompound(page))) - if (compound_trans_head(page) != page) { + if (compound_head(page) != page) { pr_crit("page tail used for block I/O\n"); BUG(); } diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 6f3fbc48a6c7..22080eb6aff6 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -138,12 +138,12 @@ static bool is_invalid_reserved_pfn(unsigned long pfn) if (pfn_valid(pfn)) { bool reserved; struct page *tail = pfn_to_page(pfn); - struct page *head = compound_trans_head(tail); + struct page *head = compound_head(tail); reserved = !!(PageReserved(head)); if (head != tail) { /* * "head" is not a dangling pointer - * (compound_trans_head takes care of that) + * (compound_head takes care of that) * but the hugepage may have been split * from under us (and we may not hold a * reference count on the head page so it can diff --git a/fs/proc/page.c b/fs/proc/page.c index b8730d9ebaee..2a8cc94bb641 100644 --- a/fs/proc/page.c +++ b/fs/proc/page.c @@ -121,7 +121,7 @@ u64 stable_page_flags(struct page *page) * just checks PG_head/PG_tail, so we need to check PageLRU to make * sure a given page is a thp, not a non-huge compound page. */ - else if (PageTransCompound(page) && PageLRU(compound_trans_head(page))) + else if (PageTransCompound(page) && PageLRU(compound_head(page))) u |= 1 << KPF_THP; /* diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 528454c2caa9..a193bb3e4138 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -159,23 +159,6 @@ 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); @@ -205,7 +188,6 @@ 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 3bf21c3502d0..a9a48309f045 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -361,8 +361,18 @@ 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; } @@ -444,7 +444,7 @@ static void break_cow(struct rmap_item *rmap_item) static struct page *page_trans_compound_anon(struct page *page) { if (PageTransCompound(page)) { - struct page *head = compound_trans_head(page); + struct page *head = compound_head(page); /* * head may actually be splitted and freed from under * us but it's ok here. diff --git a/mm/memory-failure.c b/mm/memory-failure.c index e386beefc994..59c62fa75c5a 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1544,7 +1544,7 @@ int soft_offline_page(struct page *page, int flags) { int ret; unsigned long pfn = page_to_pfn(page); - struct page *hpage = compound_trans_head(page); + struct page *hpage = compound_head(page); if (PageHWPoison(page)) { pr_info("soft offline: %#lx page already poisoned\n", pfn); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 2ee0fd313f03..0ab02fb8e9b1 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -360,9 +360,11 @@ void prep_compound_page(struct page *page, unsigned long order) __SetPageHead(page); for (i = 1; i < nr_pages; i++) { struct page *p = page + i; - __SetPageTail(p); set_page_count(p, 0); p->first_page = page; + /* Make sure p->first_page is always valid for PageTail() */ + smp_wmb(); + __SetPageTail(p); } } diff --git a/mm/swap.c b/mm/swap.c index ea58dbde788e..4e35f3ff0427 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -81,7 +81,7 @@ static void put_compound_page(struct page *page) { if (unlikely(PageTail(page))) { /* __split_huge_page_refcount can run under us */ - struct page *page_head = compound_trans_head(page); + struct page *page_head = compound_head(page); if (likely(page != page_head && get_page_unless_zero(page_head))) { @@ -219,7 +219,7 @@ bool __get_page_tail(struct page *page) */ unsigned long flags; bool got = false; - struct page *page_head = compound_trans_head(page); + struct page *page_head = compound_head(page); if (likely(page != page_head && get_page_unless_zero(page_head))) { /* Ref to put_compound_page() comment. */ diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index eb99458f5b68..8cf1cd2fadaa 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -105,12 +105,12 @@ bool kvm_is_mmio_pfn(pfn_t pfn) if (pfn_valid(pfn)) { int reserved; struct page *tail = pfn_to_page(pfn); - struct page *head = compound_trans_head(tail); + struct page *head = compound_head(tail); reserved = PageReserved(head); if (head != tail) { /* * "head" is not a dangling pointer - * (compound_trans_head takes care of that) + * (compound_head takes care of that) * but the hugepage may have been splitted * from under us (and we may not hold a * reference count on the head page so it can |