drm: Document device unplug infrastructure

While at it, also ocd and give them a consistent drm_dev_ prefix, like
the other device instance functionality. Plus move the functions into
the right places.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170802115604.12734-3-daniel.vetter@ffwll.ch

10 files changed, 31 insertions, 13 deletions

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 2ed2d919beae..39191e5c240e 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -291,7 +291,7 @@ struct drm_minor *drm_minor_acquire(unsigned int minor_id)
 
 	if (!minor) {
 		return ERR_PTR(-ENODEV);
-	} else if (drm_device_is_unplugged(minor->dev)) {
+	} else if (drm_dev_is_unplugged(minor->dev)) {
 		drm_dev_unref(minor->dev);
 		return ERR_PTR(-ENODEV);
 	}
@@ -364,7 +364,22 @@ void drm_put_dev(struct drm_device *dev)
 }
 EXPORT_SYMBOL(drm_put_dev);
 
-void drm_unplug_dev(struct drm_device *dev)
+static void drm_device_set_unplugged(struct drm_device *dev)
+{
+	smp_wmb();
+	atomic_set(&dev->unplugged, 1);
+}
+
+/**
+ * drm_dev_unplug - unplug a DRM device
+ * @dev: DRM device
+ *
+ * This unplugs a hotpluggable DRM device, which makes it inaccessible to
+ * userspace operations. Entry-points can use drm_dev_is_unplugged(). This
+ * essentially unregisters the device like drm_dev_unregister(), but can be
+ * called while there are still open users of @dev.
+ */
+void drm_dev_unplug(struct drm_device *dev)
 {
 	/* for a USB device */
 	if (drm_core_check_feature(dev, DRIVER_MODESET))
@@ -383,7 +398,7 @@ void drm_unplug_dev(struct drm_device *dev)
 	}
 	mutex_unlock(&drm_global_mutex);
 }
-EXPORT_SYMBOL(drm_unplug_dev);
+EXPORT_SYMBOL(drm_dev_unplug);
 
 /*
  * DRM internal mount
@@ -835,6 +850,9 @@ EXPORT_SYMBOL(drm_dev_register);
  * drm_dev_register() but does not deallocate the device. The caller must call
  * drm_dev_unref() to drop their final reference.
  *
+ * A special form of unregistering for hotpluggable devices is drm_dev_unplug(),
+ * which can be called while there are still open users of @dev.
+ *
  * This should be called first in the device teardown code to make sure
  * userspace can't access the device instance any more.
  */
diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index 59b75a974357..b3c6e997ccdb 100644
--- a/drivers/gpu/drm/drm_file.c
+++ b/drivers/gpu/drm/drm_file.c
@@ -436,7 +436,7 @@ int drm_release(struct inode *inode, struct file *filp)
 
 	if (!--dev->open_count) {
 		drm_lastclose(dev);
-		if (drm_device_is_unplugged(dev))
+		if (drm_dev_is_unplugged(dev))
 			drm_put_dev(dev);
 	}
 	mutex_unlock(&drm_global_mutex);
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index a8d396bed6a4..ad4e9cfe48a2 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -1001,7 +1001,7 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
 	struct drm_vma_offset_node *node;
 	int ret;
 
-	if (drm_device_is_unplugged(dev))
+	if (drm_dev_is_unplugged(dev))
 		return -ENODEV;
 
 	drm_vma_offset_lock_lookup(dev->vma_offset_manager);
diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
index 275ab872b34f..f4e00571839d 100644
--- a/drivers/gpu/drm/drm_gem_cma_helper.c
+++ b/drivers/gpu/drm/drm_gem_cma_helper.c
@@ -390,7 +390,7 @@ unsigned long drm_gem_cma_get_unmapped_area(struct file *filp,
 	struct drm_device *dev = priv->minor->dev;
 	struct drm_vma_offset_node *node;
 
-	if (drm_device_is_unplugged(dev))
+	if (drm_dev_is_unplugged(dev))
 		return -ENODEV;
 
 	drm_vma_offset_lock_lookup(dev->vma_offset_manager);
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 8bfeb32f8a10..d920b2118a39 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -716,7 +716,7 @@ long drm_ioctl_kernel(struct file *file, drm_ioctl_t *func, void *kdata,
 	struct drm_device *dev = file_priv->minor->dev;
 	int retcode;
 
-	if (drm_device_is_unplugged(dev))
+	if (drm_dev_is_unplugged(dev))
 		return -ENODEV;
 
 	retcode = drm_ioctl_permit(flags, file_priv);
@@ -765,7 +765,7 @@ long drm_ioctl(struct file *filp,
 
 	dev = file_priv->minor->dev;
 
-	if (drm_device_is_unplugged(dev))
+	if (drm_dev_is_unplugged(dev))
 		return -ENODEV;
 
 	is_driver_ioctl = nr >= DRM_COMMAND_BASE && nr < DRM_COMMAND_END;
diff --git a/drivers/gpu/drm/drm_vm.c b/drivers/gpu/drm/drm_vm.c
index 1170b3209a12..13a59ed2afbc 100644
--- a/drivers/gpu/drm/drm_vm.c
+++ b/drivers/gpu/drm/drm_vm.c
@@ -631,7 +631,7 @@ int drm_legacy_mmap(struct file *filp, struct vm_area_struct *vma)
 	struct drm_device *dev = priv->minor->dev;
 	int ret;
 
-	if (drm_device_is_unplugged(dev))
+	if (drm_dev_is_unplugged(dev))
 		return -ENODEV;
 
 	mutex_lock(&dev->struct_mutex);
diff --git a/drivers/gpu/drm/tinydrm/core/tinydrm-pipe.c b/drivers/gpu/drm/tinydrm/core/tinydrm-pipe.c
index f224b54a30f6..177e9d861001 100644
--- a/drivers/gpu/drm/tinydrm/core/tinydrm-pipe.c
+++ b/drivers/gpu/drm/tinydrm/core/tinydrm-pipe.c
@@ -56,7 +56,7 @@ static const struct drm_connector_helper_funcs tinydrm_connector_hfuncs = {
 static enum drm_connector_status
 tinydrm_connector_detect(struct drm_connector *connector, bool force)
 {
-	if (drm_device_is_unplugged(connector->dev))
+	if (drm_dev_is_unplugged(connector->dev))
 		return connector_status_disconnected;
 
 	return connector->status;
diff --git a/drivers/gpu/drm/udl/udl_connector.c b/drivers/gpu/drm/udl/udl_connector.c
index d2f57c52f7db..9f9a49748d17 100644
--- a/drivers/gpu/drm/udl/udl_connector.c
+++ b/drivers/gpu/drm/udl/udl_connector.c
@@ -96,7 +96,7 @@ static int udl_mode_valid(struct drm_connector *connector,
 static enum drm_connector_status
 udl_detect(struct drm_connector *connector, bool force)
 {
-	if (drm_device_is_unplugged(connector->dev))
+	if (drm_dev_is_unplugged(connector->dev))
 		return connector_status_disconnected;
 	return connector_status_connected;
 }
diff --git a/drivers/gpu/drm/udl/udl_drv.c b/drivers/gpu/drm/udl/udl_drv.c
index 0f02e1acf0ba..96c44ede5d69 100644
--- a/drivers/gpu/drm/udl/udl_drv.c
+++ b/drivers/gpu/drm/udl/udl_drv.c
@@ -102,7 +102,7 @@ static void udl_usb_disconnect(struct usb_interface *interface)
 	drm_kms_helper_poll_disable(dev);
 	udl_fbdev_unplug(dev);
 	udl_drop_usb(dev);
-	drm_unplug_dev(dev);
+	drm_dev_unplug(dev);
 }
 
 /*
diff --git a/drivers/gpu/drm/udl/udl_fb.c b/drivers/gpu/drm/udl/udl_fb.c
index a5c54dc60def..77a2c59c56a1 100644
--- a/drivers/gpu/drm/udl/udl_fb.c
+++ b/drivers/gpu/drm/udl/udl_fb.c
@@ -198,7 +198,7 @@ static int udl_fb_open(struct fb_info *info, int user)
 	struct udl_device *udl = dev->dev_private;
 
 	/* If the USB device is gone, we don't accept new opens */
-	if (drm_device_is_unplugged(udl->ddev))
+	if (drm_dev_is_unplugged(udl->ddev))
 		return -ENODEV;
 
 	ufbdev->fb_count++;