ARM: dts: add support for TX6S with LVDS output

[karo-tx-linux.git] / mm / huge_memory.c

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index e60837dc785c4ce35f579374527587c77665ecce..33514d88fef9b041cef11c74717091eec4805f80 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -941,6 +941,37 @@ unlock:
        spin_unlock(ptl);
 }
 
+/*
+ * Save CONFIG_DEBUG_PAGEALLOC from faulting falsely on tail pages
+ * during copy_user_huge_page()'s copy_page_rep(): in the case when
+ * the source page gets split and a tail freed before copy completes.
+ * Called under pmd_lock of checked pmd, so safe from splitting itself.
+ */
+static void get_user_huge_page(struct page *page)
+{
+       if (IS_ENABLED(CONFIG_DEBUG_PAGEALLOC)) {
+               struct page *endpage = page + HPAGE_PMD_NR;
+
+               atomic_add(HPAGE_PMD_NR, &page->_count);
+               while (++page < endpage)
+                       get_huge_page_tail(page);
+       } else {
+               get_page(page);
+       }
+}
+
+static void put_user_huge_page(struct page *page)
+{
+       if (IS_ENABLED(CONFIG_DEBUG_PAGEALLOC)) {
+               struct page *endpage = page + HPAGE_PMD_NR;
+
+               while (page < endpage)
+                       put_page(page++);
+       } else {
+               put_page(page);
+       }
+}
+
 static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
                                        struct vm_area_struct *vma,
                                        unsigned long address,
@@ -1074,7 +1105,7 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
                ret |= VM_FAULT_WRITE;
                goto out_unlock;
        }
-       get_page(page);
+       get_user_huge_page(page);
        spin_unlock(ptl);
 alloc:
        if (transparent_hugepage_enabled(vma) &&
@@ -1095,7 +1126,7 @@ alloc:
                                split_huge_page(page);
                                ret |= VM_FAULT_FALLBACK;
                        }
-                       put_page(page);
+                       put_user_huge_page(page);
                }
                count_vm_event(THP_FAULT_FALLBACK);
                goto out;
@@ -1105,7 +1136,7 @@ alloc:
                put_page(new_page);
                if (page) {
                        split_huge_page(page);
-                       put_page(page);
+                       put_user_huge_page(page);
                } else
                        split_huge_page_pmd(vma, address, pmd);
                ret |= VM_FAULT_FALLBACK;
@@ -1127,7 +1158,7 @@ alloc:
 
        spin_lock(ptl);
        if (page)
-               put_page(page);
+               put_user_huge_page(page);
        if (unlikely(!pmd_same(*pmd, orig_pmd))) {
                spin_unlock(ptl);
                mem_cgroup_uncharge_page(new_page);
@@ -2392,8 +2423,6 @@ static void collapse_huge_page(struct mm_struct *mm,
        pmd = mm_find_pmd(mm, address);
        if (!pmd)
                goto out;
-       if (pmd_trans_huge(*pmd))
-               goto out;
 
        anon_vma_lock_write(vma->anon_vma);
 
@@ -2492,8 +2521,6 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
        pmd = mm_find_pmd(mm, address);
        if (!pmd)
                goto out;
-       if (pmd_trans_huge(*pmd))
-               goto out;
 
        memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load));
        pte = pte_offset_map_lock(mm, pmd, address, &ptl);
@@ -2846,12 +2873,22 @@ void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address,
 static void split_huge_page_address(struct mm_struct *mm,
                                    unsigned long address)
 {
+       pgd_t *pgd;
+       pud_t *pud;
        pmd_t *pmd;
 
        VM_BUG_ON(!(address & ~HPAGE_PMD_MASK));
 
-       pmd = mm_find_pmd(mm, address);
-       if (!pmd)
+       pgd = pgd_offset(mm, address);
+       if (!pgd_present(*pgd))
+               return;
+
+       pud = pud_offset(pgd, address);
+       if (!pud_present(*pud))
+               return;
+
+       pmd = pmd_offset(pud, address);
+       if (!pmd_present(*pmd))
                return;
        /*
         * Caller holds the mmap_sem write mode, so a huge pmd cannot