staging/android: make sync_timeline internal to sw_sync

The only use sync_timeline will have in upstream kernel is for debugging
through the SW_SYNC interface. So make it internal to SW_SYNC to avoid
people use it in the future.

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/Kconfig

@@ -24,26 +24,18 @@ config ANDROID_LOW_MEMORY_KILLER
 	  scripts (/init.rc), and it defines priority values with minimum free memory size
 	  for each priority.
 
-config SYNC
-	bool "Synchronization framework"
-	default n
-	select ANON_INODES
-	select DMA_SHARED_BUFFER
-	---help---
-	  This option enables the framework for synchronization between multiple
-	  drivers.  Sync implementations can take advantage of hardware
-	  synchronization built into devices like GPUs.
-
 config SW_SYNC
-	bool "Software synchronization objects"
+	bool "Software synchronization framework"
 	default n
-	depends on SYNC
 	depends on SYNC_FILE
 	---help---
 	  A sync object driver that uses a 32bit counter to coordinate
 	  synchronization.  Useful when there is no hardware primitive backing
 	  the synchronization.
 
+	  WARNING: improper use of this can result in deadlocking kernel
+	  drivers from userspace. Intended for test and debug only.
+
 source "drivers/staging/android/ion/Kconfig"
 
 endif # if ANDROID

drivers/staging/android/Makefile

@@ -4,5 +4,4 @@ obj-y					+= ion/
 
 obj-$(CONFIG_ASHMEM)			+= ashmem.o
 obj-$(CONFIG_ANDROID_LOW_MEMORY_KILLER)	+= lowmemorykiller.o
-obj-$(CONFIG_SYNC)			+= sync.o sync_debug.o
+obj-$(CONFIG_SW_SYNC)			+= sw_sync.o sync_debug.o
-obj-$(CONFIG_SW_SYNC)			+= sw_sync.o

drivers/staging/android/sw_sync.c

@@ -17,11 +17,231 @@
 #include <linux/file.h>
 #include <linux/fs.h>
 #include <linux/uaccess.h>
+#include <linux/slab.h>
 #include <linux/sync_file.h>
 
 #include "uapi/sw_sync.h"
 #include "sync.h"
 
+#define CREATE_TRACE_POINTS
+#include "trace/sync.h"
+
+static const struct fence_ops timeline_fence_ops;
+
+static inline struct sync_pt *fence_to_sync_pt(struct fence *fence)
+{
+	if (fence->ops != &timeline_fence_ops)
+		return NULL;
+	return container_of(fence, struct sync_pt, base);
+}
+
+/**
+ * sync_timeline_create() - creates a sync object
+ * @drv_name:	sync_timeline driver name
+ * @name:	sync_timeline name
+ *
+ * Creates a new sync_timeline. Returns the sync_timeline object or NULL in
+ * case of error.
+ */
+struct sync_timeline *sync_timeline_create(const char *drv_name,
+					   const char *name)
+{
+	struct sync_timeline *obj;
+
+	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
+	if (!obj)
+		return NULL;
+
+	kref_init(&obj->kref);
+	obj->context = fence_context_alloc(1);
+	strlcpy(obj->name, name, sizeof(obj->name));
+	strlcpy(obj->drv_name, drv_name, sizeof(obj->drv_name));
+
+	INIT_LIST_HEAD(&obj->child_list_head);
+	INIT_LIST_HEAD(&obj->active_list_head);
+	spin_lock_init(&obj->child_list_lock);
+
+	sync_timeline_debug_add(obj);
+
+	return obj;
+}
+
+static void sync_timeline_free(struct kref *kref)
+{
+	struct sync_timeline *obj =
+		container_of(kref, struct sync_timeline, kref);
+
+	sync_timeline_debug_remove(obj);
+
+	kfree(obj);
+}
+
+static void sync_timeline_get(struct sync_timeline *obj)
+{
+	kref_get(&obj->kref);
+}
+
+static void sync_timeline_put(struct sync_timeline *obj)
+{
+	kref_put(&obj->kref, sync_timeline_free);
+}
+
+/**
+ * sync_timeline_destroy() - destroys a sync object
+ * @obj:	sync_timeline to destroy
+ *
+ * A sync implementation should call this when the @obj is going away
+ * (i.e. module unload.)  @obj won't actually be freed until all its children
+ * fences are freed.
+ */
+static void sync_timeline_destroy(struct sync_timeline *obj)
+{
+	obj->destroyed = true;
+	/*
+	 * Ensure timeline is marked as destroyed before
+	 * changing timeline's fences status.
+	 */
+	smp_wmb();
+
+	sync_timeline_put(obj);
+}
+
+/**
+ * sync_timeline_signal() - signal a status change on a sync_timeline
+ * @obj:	sync_timeline to signal
+ * @inc:	num to increment on timeline->value
+ *
+ * A sync implementation should call this any time one of it's fences
+ * has signaled or has an error condition.
+ */
+static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc)
+{
+	unsigned long flags;
+	struct sync_pt *pt, *next;
+
+	trace_sync_timeline(obj);
+
+	spin_lock_irqsave(&obj->child_list_lock, flags);
+
+	obj->value += inc;
+
+	list_for_each_entry_safe(pt, next, &obj->active_list_head,
+				 active_list) {
+		if (fence_is_signaled_locked(&pt->base))
+			list_del_init(&pt->active_list);
+	}
+
+	spin_unlock_irqrestore(&obj->child_list_lock, flags);
+}
+
+/**
+ * sync_pt_create() - creates a sync pt
+ * @parent:	fence's parent sync_timeline
+ * @size:	size to allocate for this pt
+ * @inc:	value of the fence
+ *
+ * Creates a new sync_pt as a child of @parent.  @size bytes will be
+ * allocated allowing for implementation specific data to be kept after
+ * the generic sync_timeline struct. Returns the sync_pt object or
+ * NULL in case of error.
+ */
+static struct sync_pt *sync_pt_create(struct sync_timeline *obj, int size,
+			     unsigned int value)
+{
+	unsigned long flags;
+	struct sync_pt *pt;
+
+	if (size < sizeof(*pt))
+		return NULL;
+
+	pt = kzalloc(size, GFP_KERNEL);
+	if (!pt)
+		return NULL;
+
+	spin_lock_irqsave(&obj->child_list_lock, flags);
+	sync_timeline_get(obj);
+	fence_init(&pt->base, &timeline_fence_ops, &obj->child_list_lock,
+		   obj->context, value);
+	list_add_tail(&pt->child_list, &obj->child_list_head);
+	INIT_LIST_HEAD(&pt->active_list);
+	spin_unlock_irqrestore(&obj->child_list_lock, flags);
+	return pt;
+}
+
+static const char *timeline_fence_get_driver_name(struct fence *fence)
+{
+	struct sync_timeline *parent = fence_parent(fence);
+
+	return parent->drv_name;
+}
+
+static const char *timeline_fence_get_timeline_name(struct fence *fence)
+{
+	struct sync_timeline *parent = fence_parent(fence);
+
+	return parent->name;
+}
+
+static void timeline_fence_release(struct fence *fence)
+{
+	struct sync_pt *pt = fence_to_sync_pt(fence);
+	struct sync_timeline *parent = fence_parent(fence);
+	unsigned long flags;
+
+	spin_lock_irqsave(fence->lock, flags);
+	list_del(&pt->child_list);
+	if (WARN_ON_ONCE(!list_empty(&pt->active_list)))
+		list_del(&pt->active_list);
+	spin_unlock_irqrestore(fence->lock, flags);
+
+	sync_timeline_put(parent);
+	fence_free(fence);
+}
+
+static bool timeline_fence_signaled(struct fence *fence)
+{
+	struct sync_timeline *parent = fence_parent(fence);
+
+	return (fence->seqno > parent->value) ? false : true;
+}
+
+static bool timeline_fence_enable_signaling(struct fence *fence)
+{
+	struct sync_pt *pt = fence_to_sync_pt(fence);
+	struct sync_timeline *parent = fence_parent(fence);
+
+	if (timeline_fence_signaled(fence))
+		return false;
+
+	list_add_tail(&pt->active_list, &parent->active_list_head);
+	return true;
+}
+
+static void timeline_fence_value_str(struct fence *fence,
+				    char *str, int size)
+{
+	snprintf(str, size, "%d", fence->seqno);
+}
+
+static void timeline_fence_timeline_value_str(struct fence *fence,
+					     char *str, int size)
+{
+	struct sync_timeline *parent = fence_parent(fence);
+
+	snprintf(str, size, "%d", parent->value);
+}
+
+static const struct fence_ops timeline_fence_ops = {
+	.get_driver_name = timeline_fence_get_driver_name,
+	.get_timeline_name = timeline_fence_get_timeline_name,
+	.enable_signaling = timeline_fence_enable_signaling,
+	.signaled = timeline_fence_signaled,
+	.wait = fence_default_wait,
+	.release = timeline_fence_release,
+	.fence_value_str = timeline_fence_value_str,
+	.timeline_value_str = timeline_fence_timeline_value_str,
+};
+
 /*
  * *WARNING*
  *

drivers/staging/android/sync.c

@@ -1,199 +0,0 @@
-/*
- * drivers/base/sync.c
- *
- * Copyright (C) 2012 Google, Inc.
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- */
-
-#include <linux/export.h>
-#include <linux/slab.h>
-
-#include "sync.h"
-
-#define CREATE_TRACE_POINTS
-#include "trace/sync.h"
-
-struct sync_timeline *sync_timeline_create(const char *drv_name,
-					   const char *name)
-{
-	struct sync_timeline *obj;
-
-	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
-	if (!obj)
-		return NULL;
-
-	kref_init(&obj->kref);
-	obj->context = fence_context_alloc(1);
-	strlcpy(obj->name, name, sizeof(obj->name));
-	strlcpy(obj->drv_name, drv_name, sizeof(obj->drv_name));
-
-	INIT_LIST_HEAD(&obj->child_list_head);
-	INIT_LIST_HEAD(&obj->active_list_head);
-	spin_lock_init(&obj->child_list_lock);
-
-	sync_timeline_debug_add(obj);
-
-	return obj;
-}
-EXPORT_SYMBOL(sync_timeline_create);
-
-static void sync_timeline_free(struct kref *kref)
-{
-	struct sync_timeline *obj =
-		container_of(kref, struct sync_timeline, kref);
-
-	sync_timeline_debug_remove(obj);
-
-	kfree(obj);
-}
-
-static void sync_timeline_get(struct sync_timeline *obj)
-{
-	kref_get(&obj->kref);
-}
-
-static void sync_timeline_put(struct sync_timeline *obj)
-{
-	kref_put(&obj->kref, sync_timeline_free);
-}
-
-void sync_timeline_destroy(struct sync_timeline *obj)
-{
-	obj->destroyed = true;
-	/*
-	 * Ensure timeline is marked as destroyed before
-	 * changing timeline's fences status.
-	 */
-	smp_wmb();
-
-	sync_timeline_put(obj);
-}
-EXPORT_SYMBOL(sync_timeline_destroy);
-
-void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc)
-{
-	unsigned long flags;
-	struct sync_pt *pt, *next;
-
-	trace_sync_timeline(obj);
-
-	spin_lock_irqsave(&obj->child_list_lock, flags);
-
-	obj->value += inc;
-
-	list_for_each_entry_safe(pt, next, &obj->active_list_head,
-				 active_list) {
-		if (fence_is_signaled_locked(&pt->base))
-			list_del_init(&pt->active_list);
-	}
-
-	spin_unlock_irqrestore(&obj->child_list_lock, flags);
-}
-EXPORT_SYMBOL(sync_timeline_signal);
-
-struct sync_pt *sync_pt_create(struct sync_timeline *obj, int size,
-			     unsigned int value)
-{
-	unsigned long flags;
-	struct sync_pt *pt;
-
-	if (size < sizeof(*pt))
-		return NULL;
-
-	pt = kzalloc(size, GFP_KERNEL);
-	if (!pt)
-		return NULL;
-
-	spin_lock_irqsave(&obj->child_list_lock, flags);
-	sync_timeline_get(obj);
-	fence_init(&pt->base, &timeline_fence_ops, &obj->child_list_lock,
-		   obj->context, value);
-	list_add_tail(&pt->child_list, &obj->child_list_head);
-	INIT_LIST_HEAD(&pt->active_list);
-	spin_unlock_irqrestore(&obj->child_list_lock, flags);
-	return pt;
-}
-EXPORT_SYMBOL(sync_pt_create);
-
-static const char *timeline_fence_get_driver_name(struct fence *fence)
-{
-	struct sync_timeline *parent = fence_parent(fence);
-
-	return parent->drv_name;
-}
-
-static const char *timeline_fence_get_timeline_name(struct fence *fence)
-{
-	struct sync_timeline *parent = fence_parent(fence);
-
-	return parent->name;
-}
-
-static void timeline_fence_release(struct fence *fence)
-{
-	struct sync_pt *pt = fence_to_sync_pt(fence);
-	struct sync_timeline *parent = fence_parent(fence);
-	unsigned long flags;
-
-	spin_lock_irqsave(fence->lock, flags);
-	list_del(&pt->child_list);
-	if (WARN_ON_ONCE(!list_empty(&pt->active_list)))
-		list_del(&pt->active_list);
-	spin_unlock_irqrestore(fence->lock, flags);
-
-	sync_timeline_put(parent);
-	fence_free(fence);
-}
-
-static bool timeline_fence_signaled(struct fence *fence)
-{
-	struct sync_timeline *parent = fence_parent(fence);
-
-	return (fence->seqno > parent->value) ? false : true;
-}
-
-static bool timeline_fence_enable_signaling(struct fence *fence)
-{
-	struct sync_pt *pt = fence_to_sync_pt(fence);
-	struct sync_timeline *parent = fence_parent(fence);
-
-	if (timeline_fence_signaled(fence))
-		return false;
-
-	list_add_tail(&pt->active_list, &parent->active_list_head);
-	return true;
-}
-
-static void timeline_fence_value_str(struct fence *fence,
-				    char *str, int size)
-{
-	snprintf(str, size, "%d", fence->seqno);
-}
-
-static void timeline_fence_timeline_value_str(struct fence *fence,
-					     char *str, int size)
-{
-	struct sync_timeline *parent = fence_parent(fence);
-
-	snprintf(str, size, "%d", parent->value);
-}
-
-const struct fence_ops timeline_fence_ops = {
-	.get_driver_name = timeline_fence_get_driver_name,
-	.get_timeline_name = timeline_fence_get_timeline_name,
-	.enable_signaling = timeline_fence_enable_signaling,
-	.signaled = timeline_fence_signaled,
-	.wait = fence_default_wait,
-	.release = timeline_fence_release,
-	.fence_value_str = timeline_fence_value_str,
-	.timeline_value_str = timeline_fence_timeline_value_str,
-};

drivers/staging/android/sync.h

@@ -69,64 +69,6 @@ struct sync_pt {
 	struct list_head active_list;
 };
 
-extern const struct fence_ops timeline_fence_ops;
-
-static inline struct sync_pt *fence_to_sync_pt(struct fence *fence)
-{
-	if (fence->ops != &timeline_fence_ops)
-		return NULL;
-	return container_of(fence, struct sync_pt, base);
-}
-
-/*
- * API for sync_timeline implementers
- */
-
-/**
- * sync_timeline_create() - creates a sync object
- * @drv_name:	sync_timeline driver name
- * @name:	sync_timeline name
- *
- * Creates a new sync_timeline. Returns the sync_timeline object or NULL in
- * case of error.
- */
-struct sync_timeline *sync_timeline_create(const char *drv_name,
-					   const char *name);
-
-/**
- * sync_timeline_destroy() - destroys a sync object
- * @obj:	sync_timeline to destroy
- *
- * A sync implementation should call this when the @obj is going away
- * (i.e. module unload.)  @obj won't actually be freed until all its children
- * fences are freed.
- */
-void sync_timeline_destroy(struct sync_timeline *obj);
-
-/**
- * sync_timeline_signal() - signal a status change on a sync_timeline
- * @obj:	sync_timeline to signal
- * @inc:	num to increment on timeline->value
- *
- * A sync implementation should call this any time one of it's fences
- * has signaled or has an error condition.
- */
-void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc);
-
-/**
- * sync_pt_create() - creates a sync pt
- * @parent:	fence's parent sync_timeline
- * @size:	size to allocate for this pt
- * @inc:	value of the fence
- *
- * Creates a new sync_pt as a child of @parent.  @size bytes will be
- * allocated allowing for implementation specific data to be kept after
- * the generic sync_timeline struct. Returns the sync_pt object or
- * NULL in case of error.
- */
-struct sync_pt *sync_pt_create(struct sync_timeline *parent, int size,
-			       unsigned int inc);
-
 #ifdef CONFIG_DEBUG_FS
 
 extern const struct file_operations sw_sync_debugfs_fops;

drivers/staging/android/sync_debug.c

@@ -193,10 +193,8 @@ static __init int sync_debugfs_init(void)
 
 	debugfs_create_file("info", 0444, dbgfs, NULL, &sync_info_debugfs_fops);
 
-#if IS_ENABLED(CONFIG_SW_SYNC)
 	debugfs_create_file("sw_sync", 0644, dbgfs, NULL,
 			    &sw_sync_debugfs_fops);
-#endif
 
 	return 0;
 }