drivers/staging/android/sw_sync.c

   1 /*
   2  * drivers/dma-buf/sw_sync.c
   3  *
   4  * Copyright (C) 2012 Google, Inc.
   5  *
   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.
   9  *
  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.
  14  *
  15  */
  16
  17 #include <linux/file.h>
  18 #include <linux/fs.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/slab.h>
  21 #include <linux/sync_file.h>
  22
  23 #include "sync_debug.h"
  24
  25 #define CREATE_TRACE_POINTS
  26 #include "trace/sync.h"
  27
  28 struct sw_sync_create_fence_data {
  29         __u32   value;
  30         char    name[32];
  31         __s32   fence; /* fd of new fence */
  32 };
  33
  34 #define SW_SYNC_IOC_MAGIC       'W'
  35
  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)
  39
  40 static const struct fence_ops timeline_fence_ops;
  41
  42 static inline struct sync_pt *fence_to_sync_pt(struct fence *fence)
  43 {
  44         if (fence->ops != &timeline_fence_ops)
  45                 return NULL;
  46         return container_of(fence, struct sync_pt, base);
  47 }
  48
  49 /**
  50  * sync_timeline_create() - creates a sync object
  51  * @name:       sync_timeline name
  52  *
  53  * Creates a new sync_timeline. Returns the sync_timeline object or NULL in
  54  * case of error.
  55  */
  56 struct sync_timeline *sync_timeline_create(const char *name)
  57 {
  58         struct sync_timeline *obj;
  59
  60         obj = kzalloc(sizeof(*obj), GFP_KERNEL);
  61         if (!obj)
  62                 return NULL;
  63
  64         kref_init(&obj->kref);
  65         obj->context = fence_context_alloc(1);
  66         strlcpy(obj->name, name, sizeof(obj->name));
  67
  68         INIT_LIST_HEAD(&obj->child_list_head);
  69         INIT_LIST_HEAD(&obj->active_list_head);
  70         spin_lock_init(&obj->child_list_lock);
  71
  72         sync_timeline_debug_add(obj);
  73
  74         return obj;
  75 }
  76
  77 static void sync_timeline_free(struct kref *kref)
  78 {
  79         struct sync_timeline *obj =
  80                 container_of(kref, struct sync_timeline, kref);
  81
  82         sync_timeline_debug_remove(obj);
  83
  84         kfree(obj);
  85 }
  86
  87 static void sync_timeline_get(struct sync_timeline *obj)
  88 {
  89         kref_get(&obj->kref);
  90 }
  91
  92 static void sync_timeline_put(struct sync_timeline *obj)
  93 {
  94         kref_put(&obj->kref, sync_timeline_free);
  95 }
  96
  97 /**
  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
 101  *
 102  * A sync implementation should call this any time one of it's fences
 103  * has signaled or has an error condition.
 104  */
 105 static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc)
 106 {
 107         unsigned long flags;
 108         struct sync_pt *pt, *next;
 109
 110         trace_sync_timeline(obj);
 111
 112         spin_lock_irqsave(&obj->child_list_lock, flags);
 113
 114         obj->value += inc;
 115
 116         list_for_each_entry_safe(pt, next, &obj->active_list_head,
 117                                  active_list) {
 118                 if (fence_is_signaled_locked(&pt->base))
 119                         list_del_init(&pt->active_list);
 120         }
 121
 122         spin_unlock_irqrestore(&obj->child_list_lock, flags);
 123 }
 124
 125 /**
 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
 130  *
 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.
 135  */
 136 static struct sync_pt *sync_pt_create(struct sync_timeline *obj, int size,
 137                              unsigned int value)
 138 {
 139         unsigned long flags;
 140         struct sync_pt *pt;
 141
 142         if (size < sizeof(*pt))
 143                 return NULL;
 144
 145         pt = kzalloc(size, GFP_KERNEL);
 146         if (!pt)
 147                 return NULL;
 148
 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);
 156         return pt;
 157 }
 158
 159 static const char *timeline_fence_get_driver_name(struct fence *fence)
 160 {
 161         return "sw_sync";
 162 }
 163
 164 static const char *timeline_fence_get_timeline_name(struct fence *fence)
 165 {
 166         struct sync_timeline *parent = fence_parent(fence);
 167
 168         return parent->name;
 169 }
 170
 171 static void timeline_fence_release(struct fence *fence)
 172 {
 173         struct sync_pt *pt = fence_to_sync_pt(fence);
 174         struct sync_timeline *parent = fence_parent(fence);
 175         unsigned long flags;
 176
 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);
 182
 183         sync_timeline_put(parent);
 184         fence_free(fence);
 185 }
 186
 187 static bool timeline_fence_signaled(struct fence *fence)
 188 {
 189         struct sync_timeline *parent = fence_parent(fence);
 190
 191         return (fence->seqno > parent->value) ? false : true;
 192 }
 193
 194 static bool timeline_fence_enable_signaling(struct fence *fence)
 195 {
 196         struct sync_pt *pt = fence_to_sync_pt(fence);
 197         struct sync_timeline *parent = fence_parent(fence);
 198
 199         if (timeline_fence_signaled(fence))
 200                 return false;
 201
 202         list_add_tail(&pt->active_list, &parent->active_list_head);
 203         return true;
 204 }
 205
 206 static void timeline_fence_value_str(struct fence *fence,
 207                                     char *str, int size)
 208 {
 209         snprintf(str, size, "%d", fence->seqno);
 210 }
 211
 212 static void timeline_fence_timeline_value_str(struct fence *fence,
 213                                              char *str, int size)
 214 {
 215         struct sync_timeline *parent = fence_parent(fence);
 216
 217         snprintf(str, size, "%d", parent->value);
 218 }
 219
 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,
 229 };
 230
 231 /*
 232  * *WARNING*
 233  *
 234  * improper use of this can result in deadlocking kernel drivers from userspace.
 235  */
 236
 237 /* opening sw_sync create a new sync obj */
 238 static int sw_sync_debugfs_open(struct inode *inode, struct file *file)
 239 {
 240         struct sync_timeline *obj;
 241         char task_comm[TASK_COMM_LEN];
 242
 243         get_task_comm(task_comm, current);
 244
 245         obj = sync_timeline_create(task_comm);
 246         if (!obj)
 247                 return -ENOMEM;
 248
 249         file->private_data = obj;
 250
 251         return 0;
 252 }
 253
 254 static int sw_sync_debugfs_release(struct inode *inode, struct file *file)
 255 {
 256         struct sync_timeline *obj = file->private_data;
 257
 258         smp_wmb();
 259
 260         sync_timeline_put(obj);
 261         return 0;
 262 }
 263
 264 static long sw_sync_ioctl_create_fence(struct sync_timeline *obj,
 265                                        unsigned long arg)
 266 {
 267         int fd = get_unused_fd_flags(O_CLOEXEC);
 268         int err;
 269         struct sync_pt *pt;
 270         struct sync_file *sync_file;
 271         struct sw_sync_create_fence_data data;
 272
 273         if (fd < 0)
 274                 return fd;
 275
 276         if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
 277                 err = -EFAULT;
 278                 goto err;
 279         }
 280
 281         pt = sync_pt_create(obj, sizeof(*pt), data.value);
 282         if (!pt) {
 283                 err = -ENOMEM;
 284                 goto err;
 285         }
 286
 287         sync_file = sync_file_create(&pt->base);
 288         if (!sync_file) {
 289                 fence_put(&pt->base);
 290                 err = -ENOMEM;
 291                 goto err;
 292         }
 293
 294         data.fence = fd;
 295         if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
 296                 fput(sync_file->file);
 297                 err = -EFAULT;
 298                 goto err;
 299         }
 300
 301         fd_install(fd, sync_file->file);
 302
 303         return 0;
 304
 305 err:
 306         put_unused_fd(fd);
 307         return err;
 308 }
 309
 310 static long sw_sync_ioctl_inc(struct sync_timeline *obj, unsigned long arg)
 311 {
 312         u32 value;
 313
 314         if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
 315                 return -EFAULT;
 316
 317         sync_timeline_signal(obj, value);
 318
 319         return 0;
 320 }
 321
 322 static long sw_sync_ioctl(struct file *file, unsigned int cmd,
 323                           unsigned long arg)
 324 {
 325         struct sync_timeline *obj = file->private_data;
 326
 327         switch (cmd) {
 328         case SW_SYNC_IOC_CREATE_FENCE:
 329                 return sw_sync_ioctl_create_fence(obj, arg);
 330
 331         case SW_SYNC_IOC_INC:
 332                 return sw_sync_ioctl_inc(obj, arg);
 333
 334         default:
 335                 return -ENOTTY;
 336         }
 337 }
 338
 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,
 344 };