arm64: dts: rockchip: rk3368-p9: add ramp-delay for syr82x dcdc

[firefly-linux-kernel-4.4.55.git] / mm / memory.c

diff --git a/mm/memory.c b/mm/memory.c
index c387430f06c319d52794152b7e100a66a10c9f68..76dcee3177146f0fa8820c5585f8674271b6f12c 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -797,6 +797,46 @@ out:
        return pfn_to_page(pfn);
 }
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
+                               pmd_t pmd)
+{
+       unsigned long pfn = pmd_pfn(pmd);
+
+       /*
+        * There is no pmd_special() but there may be special pmds, e.g.
+        * in a direct-access (dax) mapping, so let's just replicate the
+        * !HAVE_PTE_SPECIAL case from vm_normal_page() here.
+        */
+       if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
+               if (vma->vm_flags & VM_MIXEDMAP) {
+                       if (!pfn_valid(pfn))
+                               return NULL;
+                       goto out;
+               } else {
+                       unsigned long off;
+                       off = (addr - vma->vm_start) >> PAGE_SHIFT;
+                       if (pfn == vma->vm_pgoff + off)
+                               return NULL;
+                       if (!is_cow_mapping(vma->vm_flags))
+                               return NULL;
+               }
+       }
+
+       if (is_zero_pfn(pfn))
+               return NULL;
+       if (unlikely(pfn > highest_memmap_pfn))
+               return NULL;
+
+       /*
+        * NOTE! We still have PageReserved() pages in the page tables.
+        * eg. VDSO mappings can cause them to exist.
+        */
+out:
+       return pfn_to_page(pfn);
+}
+#endif
+
 /*
  * copy one vm_area from one task to the other. Assumes the page tables
  * already present in the new task to be cleared in the whole range
@@ -3399,8 +3439,18 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
        if (unlikely(pmd_none(*pmd)) &&
            unlikely(__pte_alloc(mm, vma, pmd, address)))
                return VM_FAULT_OOM;
-       /* if an huge pmd materialized from under us just retry later */
-       if (unlikely(pmd_trans_huge(*pmd)))
+       /*
+        * If a huge pmd materialized under us just retry later.  Use
+        * pmd_trans_unstable() instead of pmd_trans_huge() to ensure the pmd
+        * didn't become pmd_trans_huge under us and then back to pmd_none, as
+        * a result of MADV_DONTNEED running immediately after a huge pmd fault
+        * in a different thread of this mm, in turn leading to a misleading
+        * pmd_trans_huge() retval.  All we have to ensure is that it is a
+        * regular pmd that we can walk with pte_offset_map() and we can do that
+        * through an atomic read in C, which is what pmd_trans_unstable()
+        * provides.
+        */
+       if (unlikely(pmd_trans_unstable(pmd)))
                return 0;
        /*
         * A regular pmd is established and it can't morph into a huge pmd