1 files changed, 21 insertions, 5 deletions

diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 3a6934bf7131..5dccf057a7dd 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -67,6 +67,11 @@ static ssize_t map_size_show(struct uio_mem *mem, char *buf)
         return sprintf(buf, "0x%lx\n", mem->size);
 }
 
+static ssize_t map_offset_show(struct uio_mem *mem, char *buf)
+{
+        return sprintf(buf, "0x%lx\n", mem->addr & ~PAGE_MASK);
+}
+
 struct uio_sysfs_entry {
         struct attribute attr;
         ssize_t (*show)(struct uio_mem *, char *);
@@ -77,10 +82,13 @@ static struct uio_sysfs_entry addr_attribute =
         __ATTR(addr, S_IRUGO, map_addr_show, NULL);
 static struct uio_sysfs_entry size_attribute =
         __ATTR(size, S_IRUGO, map_size_show, NULL);
+static struct uio_sysfs_entry offset_attribute =
+        __ATTR(offset, S_IRUGO, map_offset_show, NULL);
 
 static struct attribute *attrs[] = {
         &addr_attribute.attr,
         &size_attribute.attr,
+        &offset_attribute.attr,
         NULL,   /* need to NULL terminate the list of attributes */
 };
 
@@ -482,15 +490,23 @@ static int uio_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
         struct uio_device *idev = vma->vm_private_data;
         struct page *page;
+        unsigned long offset;
 
         int mi = uio_find_mem_index(vma);
         if (mi < 0)
                 return VM_FAULT_SIGBUS;
 
+        /*
+         * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
+         * to use mem[N].
+         */
+        offset = (vmf->pgoff - mi) << PAGE_SHIFT;
+
         if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
-                page = virt_to_page(idev->info->mem[mi].addr);
+                page = virt_to_page(idev->info->mem[mi].addr + offset);
         else
-                page = vmalloc_to_page((void*)idev->info->mem[mi].addr);
+                page = vmalloc_to_page((void *)idev->info->mem[mi].addr
+                                                        + offset);
         get_page(page);
         vmf->page = page;
         return 0;
@@ -682,9 +698,9 @@ int __uio_register_device(struct module *owner,
         if (ret)
                 goto err_get_minor;
 
-        idev->dev = device_create_drvdata(uio_class->class, parent,
-                                          MKDEV(uio_major, idev->minor), idev,
-                                          "uio%d", idev->minor);
+        idev->dev = device_create(uio_class->class, parent,
+                                  MKDEV(uio_major, idev->minor), idev,
+                                  "uio%d", idev->minor);
         if (IS_ERR(idev->dev)) {
                 printk(KERN_ERR "UIO: device register failed\n");
                 ret = PTR_ERR(idev->dev);