drm: add core support for unplugging a device (v2)

Two parts to this, one is simple unplug from sysfs for the device node.

The second adds an unplugged state, if we have device opens, we
just set the unplugged state and return, if we have no device
opens we drop the drm device.

If after a lastclose we discover we are unplugged we then
drop the drm device.

v2: use an atomic for unplugged and wrap it for users,
add checks on open + mmap + ioctl entry points.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index d166bd080400..0b65fbc8a630 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -390,6 +390,10 @@ long drm_ioctl(struct file *filp,
         unsigned int usize, asize;
 
         dev = file_priv->minor->dev;
+
+        if (drm_device_is_unplugged(dev))
+                return -ENODEV;
+
         atomic_inc(&dev->ioctl_count);
         atomic_inc(&dev->counts[_DRM_STAT_IOCTLS]);
         ++file_priv->ioctl_count;