1 files changed, 14 insertions, 10 deletions

diff --git a/mm/memory.c b/mm/memory.c
index d67fd9fcf1f2..8b44f765b645 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2758,23 +2758,18 @@ void do_set_pte(struct vm_area_struct *vma, unsigned long address,
         update_mmu_cache(vma, address, pte);
 }
 
-static unsigned long fault_around_bytes = 65536;
+static unsigned long fault_around_bytes = rounddown_pow_of_two(65536);
 
-/*
- * fault_around_pages() and fault_around_mask() round down fault_around_bytes
- * to nearest page order. It's what do_fault_around() expects to see.
- */
 static inline unsigned long fault_around_pages(void)
 {
-        return rounddown_pow_of_two(fault_around_bytes) / PAGE_SIZE;
+        return fault_around_bytes >> PAGE_SHIFT;
 }
 
 static inline unsigned long fault_around_mask(void)
 {
-        return ~(rounddown_pow_of_two(fault_around_bytes) - 1) & PAGE_MASK;
+        return ~(fault_around_bytes - 1) & PAGE_MASK;
 }
 
-
 #ifdef CONFIG_DEBUG_FS
 static int fault_around_bytes_get(void *data, u64 *val)
 {
@@ -2782,11 +2777,19 @@ static int fault_around_bytes_get(void *data, u64 *val)
         return 0;
 }
 
+/*
+ * fault_around_pages() and fault_around_mask() expects fault_around_bytes
+ * rounded down to nearest page order. It's what do_fault_around() expects to
+ * see.
+ */
 static int fault_around_bytes_set(void *data, u64 val)
 {
         if (val / PAGE_SIZE > PTRS_PER_PTE)
                 return -EINVAL;
-        fault_around_bytes = val;
+        if (val > PAGE_SIZE)
+                fault_around_bytes = rounddown_pow_of_two(val);
+        else
+                fault_around_bytes = PAGE_SIZE; /* rounddown_pow_of_two(0) is undefined */
         return 0;
 }
 DEFINE_SIMPLE_ATTRIBUTE(fault_around_bytes_fops,
@@ -2882,7 +2885,8 @@ static int do_read_fault(struct mm_struct *mm, struct vm_area_struct *vma,
          * if page by the offset is not ready to be mapped (cold cache or
          * something).
          */
-        if (vma->vm_ops->map_pages && fault_around_pages() > 1) {
+        if (vma->vm_ops->map_pages && !(flags & FAULT_FLAG_NONLINEAR) &&
+            fault_around_pages() > 1) {
                 pte = pte_offset_map_lock(mm, pmd, address, &ptl);
                 do_fault_around(vma, address, pte, pgoff, flags);
                 if (!pte_same(*pte, orig_pte))