gpu: nvgpu: Fix AS IOCTL return code for failed user write

Fix return code in gk20a_as_dev_ioctl() in case of failed
copy_to_user().

Change-Id: I8b86c0dfca92c8c508006dc33673ccd926497819
Signed-off-by: Sami Kiminki <skiminki@nvidia.com>
Reviewed-on: http://git-master/r/590813
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/as_gk20a.c b/drivers/gpu/nvgpu/gk20a/as_gk20a.c
index 27608cec..dd5a5cf3 100644
--- a/drivers/gpu/nvgpu/gk20a/as_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/as_gk20a.c
@@ -284,7 +284,8 @@ long gk20a_as_dev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
         gk20a_idle(g->dev);
 
         if ((err == 0) && (_IOC_DIR(cmd) & _IOC_READ))
-                err = copy_to_user((void __user *)arg, buf, _IOC_SIZE(cmd));
+                if (copy_to_user((void __user *)arg, buf, _IOC_SIZE(cmd)))
+                        err = -EFAULT;
 
         return err;
 }