drm: error out with EBUSY when device has existing master

As requested by Adam, provide different error message for when the
device has an existing master. An audit of the following projects, shows
that the errno is used only for printf() purposes.

xorg/xserver
xorg/drivers/xf86-video-ati
xorg/drivers/xf86-video-amdgpu
xorg/drivers/xf86-video-intel
xorg/drivers/xf86-video-tegra
xorg/drivers/xf86-video-freedreno
xorg/drivers/xf86-video-nouveau
xorg/drivers/xf86-video-vmwgfx

qt/kwin/plasma
gtk/mutter/gnomeshell
efl/enlightment

Cc: Adam Jackson <ajax@redhat.com>
Suggested-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200319172930.230583-2-emil.l.velikov@gmail.com

diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
index 93c57f08bd937c04815870ce4bf98c180b197f9f..800ac39f3213df4f55304be6bbe5282f9ee3f768 100644 (file)
--- a/drivers/gpu/drm/drm_auth.c
+++ b/drivers/gpu/drm/drm_auth.c
@@ -245,7 +245,7 @@ int drm_setmaster_ioctl(struct drm_device *dev, void *data,
                goto out_unlock;
 
        if (dev->master) {
-               ret = -EINVAL;
+               ret = -EBUSY;
                goto out_unlock;
        }