Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 206 insertions, 0 deletions

diff --git a/include/drm/drm_modeset_lock.h b/include/drm/drm_modeset_lock.h
new file mode 100644
index 000000000..aafd07388
--- /dev/null
+++ b/include/drm/drm_modeset_lock.h
@@ -0,0 +1,206 @@
+/*
+ * 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;
+
+/**
+ * struct 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
+ * @trylock_only: trylock mode used in atomic contexts/panic notifiers
+ * @interruptible: whether interruptible locking should be used.
+ *
+ * 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;
+
+	/*
+	 * Trylock mode, use only for panic handlers!
+	 */
+	bool trylock_only;
+
+	/* Perform interruptible waits on this context. */
+	bool interruptible;
+};
+
+/**
+ * struct drm_modeset_lock - used for locking modeset resources.
+ * @mutex: resource locking
+ * @head: used to hold its place on &drm_atomi_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;
+};
+
+#define DRM_MODESET_ACQUIRE_INTERRUPTIBLE BIT(0)
+
+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);
+int drm_modeset_backoff(struct drm_modeset_acquire_ctx *ctx);
+
+void drm_modeset_lock_init(struct drm_modeset_lock *lock);
+
+/**
+ * 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);
+}
+
+/**
+ * drm_modeset_lock_assert_held - equivalent to lockdep_assert_held()
+ * @lock: lock to check
+ */
+static inline void drm_modeset_lock_assert_held(struct drm_modeset_lock *lock)
+{
+	lockdep_assert_held(&lock->mutex.base);
+}
+
+int drm_modeset_lock(struct drm_modeset_lock *lock,
+		struct drm_modeset_acquire_ctx *ctx);
+int __must_check drm_modeset_lock_single_interruptible(struct drm_modeset_lock *lock);
+void drm_modeset_unlock(struct drm_modeset_lock *lock);
+
+struct drm_device;
+struct drm_crtc;
+struct drm_plane;
+
+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);
+
+int drm_modeset_lock_all_ctx(struct drm_device *dev,
+			     struct drm_modeset_acquire_ctx *ctx);
+
+/**
+ * DRM_MODESET_LOCK_ALL_BEGIN - Helper to acquire modeset locks
+ * @dev: drm device
+ * @ctx: local modeset acquire context, will be dereferenced
+ * @flags: DRM_MODESET_ACQUIRE_* flags to pass to drm_modeset_acquire_init()
+ * @ret: local ret/err/etc variable to track error status
+ *
+ * Use these macros to simplify grabbing all modeset locks using a local
+ * context. This has the advantage of reducing boilerplate, but also properly
+ * checking return values where appropriate.
+ *
+ * Any code run between BEGIN and END will be holding the modeset locks.
+ *
+ * This must be paired with DRM_MODESET_LOCK_ALL_END(). We will jump back and
+ * forth between the labels on deadlock and error conditions.
+ *
+ * Drivers can acquire additional modeset locks. If any lock acquisition
+ * fails, the control flow needs to jump to DRM_MODESET_LOCK_ALL_END() with
+ * the @ret parameter containing the return value of drm_modeset_lock().
+ *
+ * Returns:
+ * The only possible value of ret immediately after DRM_MODESET_LOCK_ALL_BEGIN()
+ * is 0, so no error checking is necessary
+ */
+#define DRM_MODESET_LOCK_ALL_BEGIN(dev, ctx, flags, ret)		\
+	if (!drm_drv_uses_atomic_modeset(dev))				\
+		mutex_lock(&dev->mode_config.mutex);			\
+	drm_modeset_acquire_init(&ctx, flags);				\
+modeset_lock_retry:							\
+	ret = drm_modeset_lock_all_ctx(dev, &ctx);			\
+	if (ret)							\
+		goto modeset_lock_fail;
+
+/**
+ * DRM_MODESET_LOCK_ALL_END - Helper to release and cleanup modeset locks
+ * @dev: drm device
+ * @ctx: local modeset acquire context, will be dereferenced
+ * @ret: local ret/err/etc variable to track error status
+ *
+ * The other side of DRM_MODESET_LOCK_ALL_BEGIN(). It will bounce back to BEGIN
+ * if ret is -EDEADLK.
+ *
+ * It's important that you use the same ret variable for begin and end so
+ * deadlock conditions are properly handled.
+ *
+ * Returns:
+ * ret will be untouched unless it is -EDEADLK on entry. That means that if you
+ * successfully acquire the locks, ret will be whatever your code sets it to. If
+ * there is a deadlock or other failure with acquire or backoff, ret will be set
+ * to that failure. In both of these cases the code between BEGIN/END will not
+ * be run, so the failure will reflect the inability to grab the locks.
+ */
+#define DRM_MODESET_LOCK_ALL_END(dev, ctx, ret)				\
+modeset_lock_fail:							\
+	if (ret == -EDEADLK) {						\
+		ret = drm_modeset_backoff(&ctx);			\
+		if (!ret)						\
+			goto modeset_lock_retry;			\
+	}								\
+	drm_modeset_drop_locks(&ctx);					\
+	drm_modeset_acquire_fini(&ctx);					\
+	if (!drm_drv_uses_atomic_modeset(dev))				\
+		mutex_unlock(&dev->mode_config.mutex);
+
+#endif /* DRM_MODESET_LOCK_H_ */