kernel.h: add u64_to_user_ptr()

This function had copies in 3 different files. Unify them in kernel.h.

Cc: Joe Perches <joe@perches.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Rob Clark <robdclark@gmail.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Acked-by: Daniel Vetter <daniel.vetter@intel.com>	[drm/i915/]
Acked-by: Rob Clark <robdclark@gmail.com>		[drm/msm/]
Acked-by: Lucas Stach <l.stach@pengutronix.de>		[drm/etinav/]
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index dabc089..2889716 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -324,7 +324,7 @@
 {
 	struct drm_device *dev = obj->base.dev;
 	void *vaddr = obj->phys_handle->vaddr + args->offset;
-	char __user *user_data = to_user_ptr(args->data_ptr);
+	char __user *user_data = u64_to_user_ptr(args->data_ptr);
 	int ret = 0;
 
 	/* We manually control the domain here and pretend that it
@@ -605,7 +605,7 @@
 	int needs_clflush = 0;
 	struct sg_page_iter sg_iter;
 
-	user_data = to_user_ptr(args->data_ptr);
+	user_data = u64_to_user_ptr(args->data_ptr);
 	remain = args->size;
 
 	obj_do_bit17_swizzling = i915_gem_object_needs_bit17_swizzle(obj);
@@ -692,7 +692,7 @@
 		return 0;
 
 	if (!access_ok(VERIFY_WRITE,
-		       to_user_ptr(args->data_ptr),
+		       u64_to_user_ptr(args->data_ptr),
 		       args->size))
 		return -EFAULT;
 
@@ -783,7 +783,7 @@
 	if (ret)
 		goto out_unpin;
 
-	user_data = to_user_ptr(args->data_ptr);
+	user_data = u64_to_user_ptr(args->data_ptr);
 	remain = args->size;
 
 	offset = i915_gem_obj_ggtt_offset(obj) + args->offset;
@@ -907,7 +907,7 @@
 	int needs_clflush_before = 0;
 	struct sg_page_iter sg_iter;
 
-	user_data = to_user_ptr(args->data_ptr);
+	user_data = u64_to_user_ptr(args->data_ptr);
 	remain = args->size;
 
 	obj_do_bit17_swizzling = i915_gem_object_needs_bit17_swizzle(obj);
@@ -1036,12 +1036,12 @@
 		return 0;
 
 	if (!access_ok(VERIFY_READ,
-		       to_user_ptr(args->data_ptr),
+		       u64_to_user_ptr(args->data_ptr),
 		       args->size))
 		return -EFAULT;
 
 	if (likely(!i915.prefault_disable)) {
-		ret = fault_in_multipages_readable(to_user_ptr(args->data_ptr),
+		ret = fault_in_multipages_readable(u64_to_user_ptr(args->data_ptr),
 						   args->size);
 		if (ret)
 			return -EFAULT;