control page: use vm_insert_page() instead of remap_pfn_range()

vm_insert_page() is the simpler and preferred interface for remapping
individual pages and includes additional error checks. It suffices for
our purposes, so let's use it instead.

1 files changed, 5 insertions, 13 deletions

diff --git a/litmus/ctrldev.c b/litmus/ctrldev.c
index 6677a67cc945..294d134a4a6d 100644
--- a/litmus/ctrldev.c
+++ b/litmus/ctrldev.c
@@ -30,27 +30,19 @@ static int alloc_ctrl_page(struct task_struct *t)
 static int map_ctrl_page(struct task_struct *t, struct vm_area_struct* vma)
 {
         int err;
-        unsigned long pfn;
 
         struct page* ctrl = virt_to_page(tsk_rt(t)->ctrl_page);
 
-        /* Increase ref count. Is decreased when vma is destroyed. */
-        get_page(ctrl);
-
-        /* compute page frame number */
-        pfn = page_to_pfn(ctrl);
-
         TRACE_CUR(CTRL_NAME
-                  ": mapping %p (pfn:%lx, %lx) to 0x%lx (prot:%lx)\n",
-                  tsk_rt(t)->ctrl_page, pfn, page_to_pfn(ctrl), vma->vm_start,
+                  ": mapping %p (pfn:%lx) to 0x%lx (prot:%lx)\n",
+                  tsk_rt(t)->ctrl_page,page_to_pfn(ctrl), vma->vm_start,
                   vma->vm_page_prot);
 
-        /* Map it into the vma. Make sure to use PAGE_SHARED, otherwise
-         * userspace actually gets a copy-on-write page. */
-        err = remap_pfn_range(vma, vma->vm_start, pfn, PAGE_SIZE, PAGE_SHARED);
+        /* Map it into the vma. */
+        err = vm_insert_page(vma, vma->vm_start, ctrl);
 
         if (err)
-                TRACE_CUR(CTRL_NAME ": remap_pfn_range() failed (%d)\n", err);
+                TRACE_CUR(CTRL_NAME ": vm_insert_page() failed (%d)\n", err);
 
         return err;
 }