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>
23 #include "sync_debug.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 * @name: sync_timeline name
53 * Creates a new sync_timeline. Returns the sync_timeline object or NULL in
56 struct sync_timeline *sync_timeline_create(const char *name)
58 struct sync_timeline *obj;
60 obj = kzalloc(sizeof(*obj), GFP_KERNEL);
64 kref_init(&obj->kref);
65 obj->context = fence_context_alloc(1);
66 strlcpy(obj->name, name, sizeof(obj->name));
68 INIT_LIST_HEAD(&obj->child_list_head);
69 INIT_LIST_HEAD(&obj->active_list_head);
70 spin_lock_init(&obj->child_list_lock);
72 sync_timeline_debug_add(obj);
77 static void sync_timeline_free(struct kref *kref)
79 struct sync_timeline *obj =
80 container_of(kref, struct sync_timeline, kref);
82 sync_timeline_debug_remove(obj);
87 static void sync_timeline_get(struct sync_timeline *obj)
92 static void sync_timeline_put(struct sync_timeline *obj)
94 kref_put(&obj->kref, sync_timeline_free);
98 * sync_timeline_signal() - signal a status change on a sync_timeline
99 * @obj: sync_timeline to signal
100 * @inc: num to increment on timeline->value
102 * A sync implementation should call this any time one of it's fences
103 * has signaled or has an error condition.
105 static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc)
108 struct sync_pt *pt, *next;
110 trace_sync_timeline(obj);
112 spin_lock_irqsave(&obj->child_list_lock, flags);
116 list_for_each_entry_safe(pt, next, &obj->active_list_head,
118 if (fence_is_signaled_locked(&pt->base))
119 list_del_init(&pt->active_list);
122 spin_unlock_irqrestore(&obj->child_list_lock, flags);
126 * sync_pt_create() - creates a sync pt
127 * @parent: fence's parent sync_timeline
128 * @size: size to allocate for this pt
129 * @inc: value of the fence
131 * Creates a new sync_pt as a child of @parent. @size bytes will be
132 * allocated allowing for implementation specific data to be kept after
133 * the generic sync_timeline struct. Returns the sync_pt object or
134 * NULL in case of error.
136 static struct sync_pt *sync_pt_create(struct sync_timeline *obj, int size,
142 if (size < sizeof(*pt))
145 pt = kzalloc(size, GFP_KERNEL);
149 spin_lock_irqsave(&obj->child_list_lock, flags);
150 sync_timeline_get(obj);
151 fence_init(&pt->base, &timeline_fence_ops, &obj->child_list_lock,
152 obj->context, value);
153 list_add_tail(&pt->child_list, &obj->child_list_head);
154 INIT_LIST_HEAD(&pt->active_list);
155 spin_unlock_irqrestore(&obj->child_list_lock, flags);
159 static const char *timeline_fence_get_driver_name(struct fence *fence)
164 static const char *timeline_fence_get_timeline_name(struct fence *fence)
166 struct sync_timeline *parent = fence_parent(fence);
171 static void timeline_fence_release(struct fence *fence)
173 struct sync_pt *pt = fence_to_sync_pt(fence);
174 struct sync_timeline *parent = fence_parent(fence);
177 spin_lock_irqsave(fence->lock, flags);
178 list_del(&pt->child_list);
179 if (WARN_ON_ONCE(!list_empty(&pt->active_list)))
180 list_del(&pt->active_list);
181 spin_unlock_irqrestore(fence->lock, flags);
183 sync_timeline_put(parent);
187 static bool timeline_fence_signaled(struct fence *fence)
189 struct sync_timeline *parent = fence_parent(fence);
191 return (fence->seqno > parent->value) ? false : true;
194 static bool timeline_fence_enable_signaling(struct fence *fence)
196 struct sync_pt *pt = fence_to_sync_pt(fence);
197 struct sync_timeline *parent = fence_parent(fence);
199 if (timeline_fence_signaled(fence))
202 list_add_tail(&pt->active_list, &parent->active_list_head);
206 static void timeline_fence_value_str(struct fence *fence,
209 snprintf(str, size, "%d", fence->seqno);
212 static void timeline_fence_timeline_value_str(struct fence *fence,
215 struct sync_timeline *parent = fence_parent(fence);
217 snprintf(str, size, "%d", parent->value);
220 static const struct fence_ops timeline_fence_ops = {
221 .get_driver_name = timeline_fence_get_driver_name,
222 .get_timeline_name = timeline_fence_get_timeline_name,
223 .enable_signaling = timeline_fence_enable_signaling,
224 .signaled = timeline_fence_signaled,
225 .wait = fence_default_wait,
226 .release = timeline_fence_release,
227 .fence_value_str = timeline_fence_value_str,
228 .timeline_value_str = timeline_fence_timeline_value_str,
234 * improper use of this can result in deadlocking kernel drivers from userspace.
237 /* opening sw_sync create a new sync obj */
238 static int sw_sync_debugfs_open(struct inode *inode, struct file *file)
240 struct sync_timeline *obj;
241 char task_comm[TASK_COMM_LEN];
243 get_task_comm(task_comm, current);
245 obj = sync_timeline_create(task_comm);
249 file->private_data = obj;
254 static int sw_sync_debugfs_release(struct inode *inode, struct file *file)
256 struct sync_timeline *obj = file->private_data;
260 sync_timeline_put(obj);
264 static long sw_sync_ioctl_create_fence(struct sync_timeline *obj,
267 int fd = get_unused_fd_flags(O_CLOEXEC);
270 struct sync_file *sync_file;
271 struct sw_sync_create_fence_data data;
276 if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
281 pt = sync_pt_create(obj, sizeof(*pt), data.value);
287 sync_file = sync_file_create(&pt->base);
289 fence_put(&pt->base);
295 if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
296 fput(sync_file->file);
301 fd_install(fd, sync_file->file);
310 static long sw_sync_ioctl_inc(struct sync_timeline *obj, unsigned long arg)
314 if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
317 sync_timeline_signal(obj, value);
322 static long sw_sync_ioctl(struct file *file, unsigned int cmd,
325 struct sync_timeline *obj = file->private_data;
328 case SW_SYNC_IOC_CREATE_FENCE:
329 return sw_sync_ioctl_create_fence(obj, arg);
331 case SW_SYNC_IOC_INC:
332 return sw_sync_ioctl_inc(obj, arg);
339 const struct file_operations sw_sync_debugfs_fops = {
340 .open = sw_sync_debugfs_open,
341 .release = sw_sync_debugfs_release,
342 .unlocked_ioctl = sw_sync_ioctl,
343 .compat_ioctl = sw_sync_ioctl,