2 * drivers/dma-buf/sw_sync.c
4 * Copyright (C) 2012 Google, Inc.
6 * This software is licensed under the terms of the GNU General Public
7 * License version 2, as published by the Free Software Foundation, and
8 * may be copied, distributed, and modified under those terms.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
17 #include <linux/file.h>
19 #include <linux/uaccess.h>
20 #include <linux/slab.h>
21 #include <linux/sync_file.h>
25 #define CREATE_TRACE_POINTS
26 #include "trace/sync.h"
28 struct sw_sync_create_fence_data {
31 __s32 fence; /* fd of new fence */
34 #define SW_SYNC_IOC_MAGIC 'W'
36 #define SW_SYNC_IOC_CREATE_FENCE _IOWR(SW_SYNC_IOC_MAGIC, 0,\
37 struct sw_sync_create_fence_data)
38 #define SW_SYNC_IOC_INC _IOW(SW_SYNC_IOC_MAGIC, 1, __u32)
40 static const struct fence_ops timeline_fence_ops;
42 static inline struct sync_pt *fence_to_sync_pt(struct fence *fence)
44 if (fence->ops != &timeline_fence_ops)
46 return container_of(fence, struct sync_pt, base);
50 * sync_timeline_create() - creates a sync object
51 * @drv_name: sync_timeline driver name
52 * @name: sync_timeline name
54 * Creates a new sync_timeline. Returns the sync_timeline object or NULL in
57 struct sync_timeline *sync_timeline_create(const char *drv_name,
60 struct sync_timeline *obj;
62 obj = kzalloc(sizeof(*obj), GFP_KERNEL);
66 kref_init(&obj->kref);
67 obj->context = fence_context_alloc(1);
68 strlcpy(obj->name, name, sizeof(obj->name));
69 strlcpy(obj->drv_name, drv_name, sizeof(obj->drv_name));
71 INIT_LIST_HEAD(&obj->child_list_head);
72 INIT_LIST_HEAD(&obj->active_list_head);
73 spin_lock_init(&obj->child_list_lock);
75 sync_timeline_debug_add(obj);
80 static void sync_timeline_free(struct kref *kref)
82 struct sync_timeline *obj =
83 container_of(kref, struct sync_timeline, kref);
85 sync_timeline_debug_remove(obj);
90 static void sync_timeline_get(struct sync_timeline *obj)
95 static void sync_timeline_put(struct sync_timeline *obj)
97 kref_put(&obj->kref, sync_timeline_free);
101 * sync_timeline_destroy() - destroys a sync object
102 * @obj: sync_timeline to destroy
104 * A sync implementation should call this when the @obj is going away
105 * (i.e. module unload.) @obj won't actually be freed until all its children
108 static void sync_timeline_destroy(struct sync_timeline *obj)
112 sync_timeline_put(obj);
116 * sync_timeline_signal() - signal a status change on a sync_timeline
117 * @obj: sync_timeline to signal
118 * @inc: num to increment on timeline->value
120 * A sync implementation should call this any time one of it's fences
121 * has signaled or has an error condition.
123 static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc)
126 struct sync_pt *pt, *next;
128 trace_sync_timeline(obj);
130 spin_lock_irqsave(&obj->child_list_lock, flags);
134 list_for_each_entry_safe(pt, next, &obj->active_list_head,
136 if (fence_is_signaled_locked(&pt->base))
137 list_del_init(&pt->active_list);
140 spin_unlock_irqrestore(&obj->child_list_lock, flags);
144 * sync_pt_create() - creates a sync pt
145 * @parent: fence's parent sync_timeline
146 * @size: size to allocate for this pt
147 * @inc: value of the fence
149 * Creates a new sync_pt as a child of @parent. @size bytes will be
150 * allocated allowing for implementation specific data to be kept after
151 * the generic sync_timeline struct. Returns the sync_pt object or
152 * NULL in case of error.
154 static struct sync_pt *sync_pt_create(struct sync_timeline *obj, int size,
160 if (size < sizeof(*pt))
163 pt = kzalloc(size, GFP_KERNEL);
167 spin_lock_irqsave(&obj->child_list_lock, flags);
168 sync_timeline_get(obj);
169 fence_init(&pt->base, &timeline_fence_ops, &obj->child_list_lock,
170 obj->context, value);
171 list_add_tail(&pt->child_list, &obj->child_list_head);
172 INIT_LIST_HEAD(&pt->active_list);
173 spin_unlock_irqrestore(&obj->child_list_lock, flags);
177 static const char *timeline_fence_get_driver_name(struct fence *fence)
179 struct sync_timeline *parent = fence_parent(fence);
181 return parent->drv_name;
184 static const char *timeline_fence_get_timeline_name(struct fence *fence)
186 struct sync_timeline *parent = fence_parent(fence);
191 static void timeline_fence_release(struct fence *fence)
193 struct sync_pt *pt = fence_to_sync_pt(fence);
194 struct sync_timeline *parent = fence_parent(fence);
197 spin_lock_irqsave(fence->lock, flags);
198 list_del(&pt->child_list);
199 if (WARN_ON_ONCE(!list_empty(&pt->active_list)))
200 list_del(&pt->active_list);
201 spin_unlock_irqrestore(fence->lock, flags);
203 sync_timeline_put(parent);
207 static bool timeline_fence_signaled(struct fence *fence)
209 struct sync_timeline *parent = fence_parent(fence);
211 return (fence->seqno > parent->value) ? false : true;
214 static bool timeline_fence_enable_signaling(struct fence *fence)
216 struct sync_pt *pt = fence_to_sync_pt(fence);
217 struct sync_timeline *parent = fence_parent(fence);
219 if (timeline_fence_signaled(fence))
222 list_add_tail(&pt->active_list, &parent->active_list_head);
226 static void timeline_fence_value_str(struct fence *fence,
229 snprintf(str, size, "%d", fence->seqno);
232 static void timeline_fence_timeline_value_str(struct fence *fence,
235 struct sync_timeline *parent = fence_parent(fence);
237 snprintf(str, size, "%d", parent->value);
240 static const struct fence_ops timeline_fence_ops = {
241 .get_driver_name = timeline_fence_get_driver_name,
242 .get_timeline_name = timeline_fence_get_timeline_name,
243 .enable_signaling = timeline_fence_enable_signaling,
244 .signaled = timeline_fence_signaled,
245 .wait = fence_default_wait,
246 .release = timeline_fence_release,
247 .fence_value_str = timeline_fence_value_str,
248 .timeline_value_str = timeline_fence_timeline_value_str,
254 * improper use of this can result in deadlocking kernel drivers from userspace.
257 /* opening sw_sync create a new sync obj */
258 static int sw_sync_debugfs_open(struct inode *inode, struct file *file)
260 struct sync_timeline *obj;
261 char task_comm[TASK_COMM_LEN];
263 get_task_comm(task_comm, current);
265 obj = sync_timeline_create("sw_sync", task_comm);
269 file->private_data = obj;
274 static int sw_sync_debugfs_release(struct inode *inode, struct file *file)
276 struct sync_timeline *obj = file->private_data;
278 sync_timeline_destroy(obj);
282 static long sw_sync_ioctl_create_fence(struct sync_timeline *obj,
285 int fd = get_unused_fd_flags(O_CLOEXEC);
288 struct sync_file *sync_file;
289 struct sw_sync_create_fence_data data;
294 if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
299 pt = sync_pt_create(obj, sizeof(*pt), data.value);
305 sync_file = sync_file_create(&pt->base);
307 fence_put(&pt->base);
313 if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
314 fput(sync_file->file);
319 fd_install(fd, sync_file->file);
328 static long sw_sync_ioctl_inc(struct sync_timeline *obj, unsigned long arg)
332 if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
335 sync_timeline_signal(obj, value);
340 static long sw_sync_ioctl(struct file *file, unsigned int cmd,
343 struct sync_timeline *obj = file->private_data;
346 case SW_SYNC_IOC_CREATE_FENCE:
347 return sw_sync_ioctl_create_fence(obj, arg);
349 case SW_SYNC_IOC_INC:
350 return sw_sync_ioctl_inc(obj, arg);
357 const struct file_operations sw_sync_debugfs_fops = {
358 .open = sw_sync_debugfs_open,
359 .release = sw_sync_debugfs_release,
360 .unlocked_ioctl = sw_sync_ioctl,
361 .compat_ioctl = sw_sync_ioctl,