3 files changed, 135 insertions, 11 deletions

diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 76ccaabd0418..475ca5cf3c20 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1186,11 +1186,6 @@ static inline int drm_device_is_unplugged(struct drm_device *dev)
         return ret;
 }
 
-static inline bool drm_modeset_is_locked(struct drm_device *dev)
-{
-        return mutex_is_locked(&dev->mode_config.mutex);
-}
-
 static inline bool drm_is_render_client(const struct drm_file *file_priv)
 {
         return file_priv->minor->type == DRM_MINOR_RENDER;
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 6c295df7b0df..a7fac5686915 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -33,6 +33,7 @@
 #include <linux/hdmi.h>
 #include <drm/drm_mode.h>
 #include <drm/drm_fourcc.h>
+#include <drm/drm_modeset_lock.h>
 
 struct drm_device;
 struct drm_mode_set;
@@ -205,6 +206,10 @@ struct drm_property {
         struct list_head enum_blob_list;
 };
 
+void drm_modeset_lock_all(struct drm_device *dev);
+void drm_modeset_unlock_all(struct drm_device *dev);
+void drm_warn_on_modeset_not_all_locked(struct drm_device *dev);
+
 struct drm_crtc;
 struct drm_connector;
 struct drm_encoder;
@@ -280,6 +285,7 @@ struct drm_crtc_funcs {
  * drm_crtc - central CRTC control structure
  * @dev: parent DRM device
  * @head: list management
+ * @mutex: per-CRTC locking
  * @base: base KMS object for ID tracking etc.
  * @primary: primary plane for this CRTC
  * @cursor: cursor plane for this CRTC
@@ -314,7 +320,7 @@ struct drm_crtc {
          * state, ...) and a write lock for everything which can be update
          * without a full modeset (fb, cursor data, ...)
          */
-        struct mutex mutex;
+        struct drm_modeset_lock mutex;
 
         struct drm_mode_object base;
 
@@ -738,7 +744,8 @@ struct drm_mode_group {
  */
 struct drm_mode_config {
         struct mutex mutex; /* protects configuration (mode lists etc.) */
-        struct mutex connection_mutex; /* protects connector->encoder and encoder->crtc links */
+        struct drm_modeset_lock connection_mutex; /* protects connector->encoder and encoder->crtc links */
+        struct drm_modeset_acquire_ctx *acquire_ctx; /* for legacy _lock_all() / _unlock_all() */
         struct mutex idr_mutex; /* for IDR management */
         struct idr crtc_idr; /* use this idr for all IDs, fb, crtc, connector, modes - just makes life easier */
         /* this is limited to one for now */
@@ -839,10 +846,6 @@ struct drm_prop_enum_list {
         char *name;
 };
 
-extern void drm_modeset_lock_all(struct drm_device *dev);
-extern void drm_modeset_unlock_all(struct drm_device *dev);
-extern void drm_warn_on_modeset_not_all_locked(struct drm_device *dev);
-
 extern int drm_crtc_init_with_planes(struct drm_device *dev,
                                      struct drm_crtc *crtc,
                                      struct drm_plane *primary,
diff --git a/include/drm/drm_modeset_lock.h b/include/drm/drm_modeset_lock.h
new file mode 100644
index 000000000000..402aa7a6a058
--- /dev/null
+++ b/include/drm/drm_modeset_lock.h
@@ -0,0 +1,126 @@
+/*
+ * Copyright (C) 2014 Red Hat
+ * Author: Rob Clark <robdclark@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef DRM_MODESET_LOCK_H_
+#define DRM_MODESET_LOCK_H_
+
+#include <linux/ww_mutex.h>
+
+struct drm_modeset_lock;
+
+/**
+ * drm_modeset_acquire_ctx - locking context (see ww_acquire_ctx)
+ * @ww_ctx: base acquire ctx
+ * @contended: used internally for -EDEADLK handling
+ * @locked: list of held locks
+ *
+ * Each thread competing for a set of locks must use one acquire
+ * ctx.  And if any lock fxn returns -EDEADLK, it must backoff and
+ * retry.
+ */
+struct drm_modeset_acquire_ctx {
+
+        struct ww_acquire_ctx ww_ctx;
+
+        /**
+         * Contended lock: if a lock is contended you should only call
+         * drm_modeset_backoff() which drops locks and slow-locks the
+         * contended lock.
+         */
+        struct drm_modeset_lock *contended;
+
+        /**
+         * list of held locks (drm_modeset_lock)
+         */
+        struct list_head locked;
+};
+
+/**
+ * drm_modeset_lock - used for locking modeset resources.
+ * @mutex: resource locking
+ * @head: used to hold it's place on state->locked list when
+ *    part of an atomic update
+ *
+ * Used for locking CRTCs and other modeset resources.
+ */
+struct drm_modeset_lock {
+        /**
+         * modeset lock
+         */
+        struct ww_mutex mutex;
+
+        /**
+         * Resources that are locked as part of an atomic update are added
+         * to a list (so we know what to unlock at the end).
+         */
+        struct list_head head;
+};
+
+extern struct ww_class crtc_ww_class;
+
+void drm_modeset_acquire_init(struct drm_modeset_acquire_ctx *ctx,
+                uint32_t flags);
+void drm_modeset_acquire_fini(struct drm_modeset_acquire_ctx *ctx);
+void drm_modeset_drop_locks(struct drm_modeset_acquire_ctx *ctx);
+void drm_modeset_backoff(struct drm_modeset_acquire_ctx *ctx);
+int drm_modeset_backoff_interruptible(struct drm_modeset_acquire_ctx *ctx);
+
+/**
+ * drm_modeset_lock_init - initialize lock
+ * @lock: lock to init
+ */
+static inline void drm_modeset_lock_init(struct drm_modeset_lock *lock)
+{
+        ww_mutex_init(&lock->mutex, &crtc_ww_class);
+        INIT_LIST_HEAD(&lock->head);
+}
+
+/**
+ * drm_modeset_lock_fini - cleanup lock
+ * @lock: lock to cleanup
+ */
+static inline void drm_modeset_lock_fini(struct drm_modeset_lock *lock)
+{
+        WARN_ON(!list_empty(&lock->head));
+}
+
+/**
+ * drm_modeset_is_locked - equivalent to mutex_is_locked()
+ * @lock: lock to check
+ */
+static inline bool drm_modeset_is_locked(struct drm_modeset_lock *lock)
+{
+        return ww_mutex_is_locked(&lock->mutex);
+}
+
+int drm_modeset_lock(struct drm_modeset_lock *lock,
+                struct drm_modeset_acquire_ctx *ctx);
+int drm_modeset_lock_interruptible(struct drm_modeset_lock *lock,
+                struct drm_modeset_acquire_ctx *ctx);
+void drm_modeset_unlock(struct drm_modeset_lock *lock);
+
+struct drm_device;
+int drm_modeset_lock_all_crtcs(struct drm_device *dev,
+                struct drm_modeset_acquire_ctx *ctx);
+
+#endif /* DRM_MODESET_LOCK_H_ */