3 files changed, 60 insertions, 2 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ca9a7c6d7e97..1a12f5b9a0ab 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2961,7 +2961,17 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
                         break;
                 }
 
-                if (absent ||
+                /*
+                 * We need call hugetlb_fault for both hugepages under migration
+                 * (in which case hugetlb_fault waits for the migration,) and
+                 * hwpoisoned hugepages (in which case we need to prevent the
+                 * caller from accessing to them.) In order to do this, we use
+                 * here is_swap_pte instead of is_hugetlb_entry_migration and
+                 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
+                 * both cases, and because we can't follow correct pages
+                 * directly from any kind of swap entries.
+                 */
+                if (absent || is_swap_pte(huge_ptep_get(pte)) ||
                     ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) {
                         int ret;
 
diff --git a/mm/memory.c b/mm/memory.c
index 494526ae024a..ba94dec5b259 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -216,6 +216,7 @@ void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm)
         tlb->mm = mm;
 
         tlb->fullmm     = fullmm;
+        tlb->need_flush_all = 0;
         tlb->start      = -1UL;
         tlb->end        = 0;
         tlb->need_flush = 0;
@@ -2392,6 +2393,53 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
 }
 EXPORT_SYMBOL(remap_pfn_range);
 
+/**
+ * vm_iomap_memory - remap memory to userspace
+ * @vma: user vma to map to
+ * @start: start of area
+ * @len: size of area
+ *
+ * This is a simplified io_remap_pfn_range() for common driver use. The
+ * driver just needs to give us the physical memory range to be mapped,
+ * we'll figure out the rest from the vma information.
+ *
+ * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get
+ * whatever write-combining details or similar.
+ */
+int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
+{
+        unsigned long vm_len, pfn, pages;
+
+        /* Check that the physical memory area passed in looks valid */
+        if (start + len < start)
+                return -EINVAL;
+        /*
+         * You *really* shouldn't map things that aren't page-aligned,
+         * but we've historically allowed it because IO memory might
+         * just have smaller alignment.
+         */
+        len += start & ~PAGE_MASK;
+        pfn = start >> PAGE_SHIFT;
+        pages = (len + ~PAGE_MASK) >> PAGE_SHIFT;
+        if (pfn + pages < pfn)
+                return -EINVAL;
+
+        /* We start the mapping 'vm_pgoff' pages into the area */
+        if (vma->vm_pgoff > pages)
+                return -EINVAL;
+        pfn += vma->vm_pgoff;
+        pages -= vma->vm_pgoff;
+
+        /* Can we fit all of the mapping? */
+        vm_len = vma->vm_end - vma->vm_start;
+        if (vm_len >> PAGE_SHIFT > pages)
+                return -EINVAL;
+
+        /* Ok, let it rip */
+        return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
+}
+EXPORT_SYMBOL(vm_iomap_memory);
+
 static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
                                      unsigned long addr, unsigned long end,
                                      pte_fn_t fn, void *data)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 88c5fed8b9a4..669fba39be1a 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3188,9 +3188,9 @@ int kswapd_run(int nid)
         if (IS_ERR(pgdat->kswapd)) {
                 /* failure at boot is fatal */
                 BUG_ON(system_state == SYSTEM_BOOTING);
-                pgdat->kswapd = NULL;
                 pr_err("Failed to start kswapd on node %d\n", nid);
                 ret = PTR_ERR(pgdat->kswapd);
+                pgdat->kswapd = NULL;
         }
         return ret;
 }