[PATCH v8 3/7] drm/lease: Add a helper to tell whether a lease was revoked

[Maxime Ripard <mripard@kernel.org>]

drm_lease_held() only answers whether a given object is part of a lease,
and the answer can change from one call to the next. Code that needs to
look at several objects in a row has no way to tell whether the lease it
has been checking against is still around by the time it is done.

Add a helper reporting whether a lease has been revoked, so that such
code can bail out instead of acting on a lease that went away.

Signed-off-by: Maxime Ripard <mripard@kernel.org>
---
 drivers/gpu/drm/drm_lease.c | 26 ++++++++++++++++++++++++++
 include/drm/drm_lease.h     |  2 ++
 2 files changed, 28 insertions(+)

diff --git a/drivers/gpu/drm/drm_lease.c b/drivers/gpu/drm/drm_lease.c
index 5d2cf724cbd7..dd59df14dcc0 100644
--- a/drivers/gpu/drm/drm_lease.c
+++ b/drivers/gpu/drm/drm_lease.c
@@ -148,4 +148,30 @@ bool drm_lease_held(struct drm_file *file_priv, int id)
 }
 
+/*
+ * Checks whether the file is a lessee whose lease has been revoked. A
+ * lease is always revoked as a whole, so an empty one has been revoked.
+ */
+bool drm_lease_revoked(struct drm_file *file_priv)
+{
+	struct drm_master *master;
+	bool ret = false;
+
+	if (!file_priv)
+		return false;
+
+	master = drm_file_get_master(file_priv);
+	if (!master)
+		return false;
+
+	if (master->lessor) {
+		mutex_lock(&master->dev->mode_config.idr_mutex);
+		ret = idr_is_empty(&master->leases);
+		mutex_unlock(&master->dev->mode_config.idr_mutex);
+	}
+
+	drm_master_put(&master);
+	return ret;
+}
+
 /*
  * Given a bitmask of crtcs to check, reconstructs a crtc mask based on the
diff --git a/include/drm/drm_lease.h b/include/drm/drm_lease.h
index 53545b4ca9ef..03f7ea36c37c 100644
--- a/include/drm/drm_lease.h
+++ b/include/drm/drm_lease.h
@@ -21,4 +21,6 @@ bool drm_lease_held(struct drm_file *file_priv, int id);
 bool _drm_lease_held(struct drm_file *file_priv, int id);
 
+bool drm_lease_revoked(struct drm_file *file_priv);
+
 void drm_lease_revoke(struct drm_master *master);
 

-- 
2.55.0