agp/intel: Fix wrong kunmap in i830_cleanup()

Add a missing NULL check and fix the wrong address passed to kunmap()
in i830_cleanup().

Cc: stable@kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
[danvet: added cc stable]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
index 9272c38dd3c6..16a2847b7cdb 100644
--- a/drivers/char/agp/intel-gtt.c
+++ b/drivers/char/agp/intel-gtt.c
@@ -812,8 +812,10 @@ static int intel_fake_agp_fetch_size(void)
 
 static void i830_cleanup(void)
 {
-        kunmap(intel_private.i8xx_page);
-        intel_private.i8xx_flush_page = NULL;
+        if (intel_private.i8xx_flush_page) {
+                kunmap(intel_private.i8xx_flush_page);
+                intel_private.i8xx_flush_page = NULL;
+        }
 
         __free_page(intel_private.i8xx_page);
         intel_private.i8xx_page = NULL;