Check fops_get() return value
[linux-2.6.git] / drivers / gpu / drm / drm_fops.c
1 /**
2  * \file drm_fops.c
3  * File operations for DRM
4  *
5  * \author Rickard E. (Rik) Faith <faith@valinux.com>
6  * \author Daryll Strauss <daryll@valinux.com>
7  * \author Gareth Hughes <gareth@valinux.com>
8  */
9
10 /*
11  * Created: Mon Jan  4 08:58:31 1999 by faith@valinux.com
12  *
13  * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
14  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
15  * All Rights Reserved.
16  *
17  * Permission is hereby granted, free of charge, to any person obtaining a
18  * copy of this software and associated documentation files (the "Software"),
19  * to deal in the Software without restriction, including without limitation
20  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
21  * and/or sell copies of the Software, and to permit persons to whom the
22  * Software is furnished to do so, subject to the following conditions:
23  *
24  * The above copyright notice and this permission notice (including the next
25  * paragraph) shall be included in all copies or substantial portions of the
26  * Software.
27  *
28  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
29  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
30  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
31  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
32  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
33  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
34  * OTHER DEALINGS IN THE SOFTWARE.
35  */
36
37 #include "drmP.h"
38 #include <linux/poll.h>
39 #include <linux/smp_lock.h>
40
41 static int drm_open_helper(struct inode *inode, struct file *filp,
42                            struct drm_device * dev);
43
44 static int drm_setup(struct drm_device * dev)
45 {
46         int i;
47         int ret;
48
49         if (dev->driver->firstopen) {
50                 ret = dev->driver->firstopen(dev);
51                 if (ret != 0)
52                         return ret;
53         }
54
55         atomic_set(&dev->ioctl_count, 0);
56         atomic_set(&dev->vma_count, 0);
57
58         if (drm_core_check_feature(dev, DRIVER_HAVE_DMA) &&
59             !drm_core_check_feature(dev, DRIVER_MODESET)) {
60                 dev->buf_use = 0;
61                 atomic_set(&dev->buf_alloc, 0);
62
63                 i = drm_dma_setup(dev);
64                 if (i < 0)
65                         return i;
66         }
67
68         for (i = 0; i < ARRAY_SIZE(dev->counts); i++)
69                 atomic_set(&dev->counts[i], 0);
70
71         dev->sigdata.lock = NULL;
72
73         dev->queue_count = 0;
74         dev->queue_reserved = 0;
75         dev->queue_slots = 0;
76         dev->queuelist = NULL;
77         dev->context_flag = 0;
78         dev->interrupt_flag = 0;
79         dev->dma_flag = 0;
80         dev->last_context = 0;
81         dev->last_switch = 0;
82         dev->last_checked = 0;
83         init_waitqueue_head(&dev->context_wait);
84         dev->if_version = 0;
85
86         dev->ctx_start = 0;
87         dev->lck_start = 0;
88
89         dev->buf_async = NULL;
90         init_waitqueue_head(&dev->buf_readers);
91         init_waitqueue_head(&dev->buf_writers);
92
93         DRM_DEBUG("\n");
94
95         /*
96          * The kernel's context could be created here, but is now created
97          * in drm_dma_enqueue.  This is more resource-efficient for
98          * hardware that does not do DMA, but may mean that
99          * drm_select_queue fails between the time the interrupt is
100          * initialized and the time the queues are initialized.
101          */
102
103         return 0;
104 }
105
106 /**
107  * Open file.
108  *
109  * \param inode device inode
110  * \param filp file pointer.
111  * \return zero on success or a negative number on failure.
112  *
113  * Searches the DRM device with the same minor number, calls open_helper(), and
114  * increments the device open count. If the open count was previous at zero,
115  * i.e., it's the first that the device is open, then calls setup().
116  */
117 int drm_open(struct inode *inode, struct file *filp)
118 {
119         struct drm_device *dev = NULL;
120         int minor_id = iminor(inode);
121         struct drm_minor *minor;
122         int retcode = 0;
123
124         minor = idr_find(&drm_minors_idr, minor_id);
125         if (!minor)
126                 return -ENODEV;
127
128         if (!(dev = minor->dev))
129                 return -ENODEV;
130
131         retcode = drm_open_helper(inode, filp, dev);
132         if (!retcode) {
133                 atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
134                 spin_lock(&dev->count_lock);
135                 if (!dev->open_count++) {
136                         spin_unlock(&dev->count_lock);
137                         retcode = drm_setup(dev);
138                         goto out;
139                 }
140                 spin_unlock(&dev->count_lock);
141         }
142 out:
143         mutex_lock(&dev->struct_mutex);
144         if (minor->type == DRM_MINOR_LEGACY) {
145                 BUG_ON((dev->dev_mapping != NULL) &&
146                         (dev->dev_mapping != inode->i_mapping));
147                 if (dev->dev_mapping == NULL)
148                         dev->dev_mapping = inode->i_mapping;
149         }
150         mutex_unlock(&dev->struct_mutex);
151
152         return retcode;
153 }
154 EXPORT_SYMBOL(drm_open);
155
156 /**
157  * File \c open operation.
158  *
159  * \param inode device inode.
160  * \param filp file pointer.
161  *
162  * Puts the dev->fops corresponding to the device minor number into
163  * \p filp, call the \c open method, and restore the file operations.
164  */
165 int drm_stub_open(struct inode *inode, struct file *filp)
166 {
167         struct drm_device *dev = NULL;
168         struct drm_minor *minor;
169         int minor_id = iminor(inode);
170         int err = -ENODEV;
171         const struct file_operations *old_fops;
172
173         DRM_DEBUG("\n");
174
175         /* BKL pushdown: note that nothing else serializes idr_find() */
176         lock_kernel();
177         minor = idr_find(&drm_minors_idr, minor_id);
178         if (!minor)
179                 goto out;
180
181         if (!(dev = minor->dev))
182                 goto out;
183
184         old_fops = filp->f_op;
185         filp->f_op = fops_get(&dev->driver->fops);
186         if (filp->f_op == NULL) {
187                 filp->f_op = old_fops;
188                 goto out;
189         }
190         if (filp->f_op->open && (err = filp->f_op->open(inode, filp))) {
191                 fops_put(filp->f_op);
192                 filp->f_op = fops_get(old_fops);
193         }
194         fops_put(old_fops);
195
196 out:
197         unlock_kernel();
198         return err;
199 }
200
201 /**
202  * Check whether DRI will run on this CPU.
203  *
204  * \return non-zero if the DRI will run on this CPU, or zero otherwise.
205  */
206 static int drm_cpu_valid(void)
207 {
208 #if defined(__i386__)
209         if (boot_cpu_data.x86 == 3)
210                 return 0;       /* No cmpxchg on a 386 */
211 #endif
212 #if defined(__sparc__) && !defined(__sparc_v9__)
213         return 0;               /* No cmpxchg before v9 sparc. */
214 #endif
215         return 1;
216 }
217
218 /**
219  * Called whenever a process opens /dev/drm.
220  *
221  * \param inode device inode.
222  * \param filp file pointer.
223  * \param dev device.
224  * \return zero on success or a negative number on failure.
225  *
226  * Creates and initializes a drm_file structure for the file private data in \p
227  * filp and add it into the double linked list in \p dev.
228  */
229 static int drm_open_helper(struct inode *inode, struct file *filp,
230                            struct drm_device * dev)
231 {
232         int minor_id = iminor(inode);
233         struct drm_file *priv;
234         int ret;
235
236         if (filp->f_flags & O_EXCL)
237                 return -EBUSY;  /* No exclusive opens */
238         if (!drm_cpu_valid())
239                 return -EINVAL;
240
241         DRM_DEBUG("pid = %d, minor = %d\n", task_pid_nr(current), minor_id);
242
243         priv = drm_alloc(sizeof(*priv), DRM_MEM_FILES);
244         if (!priv)
245                 return -ENOMEM;
246
247         memset(priv, 0, sizeof(*priv));
248         filp->private_data = priv;
249         priv->filp = filp;
250         priv->uid = current_euid();
251         priv->pid = task_pid_nr(current);
252         priv->minor = idr_find(&drm_minors_idr, minor_id);
253         priv->ioctl_count = 0;
254         /* for compatibility root is always authenticated */
255         priv->authenticated = capable(CAP_SYS_ADMIN);
256         priv->lock_count = 0;
257
258         INIT_LIST_HEAD(&priv->lhead);
259         INIT_LIST_HEAD(&priv->fbs);
260
261         if (dev->driver->driver_features & DRIVER_GEM)
262                 drm_gem_open(dev, priv);
263
264         if (dev->driver->open) {
265                 ret = dev->driver->open(dev, priv);
266                 if (ret < 0)
267                         goto out_free;
268         }
269
270
271         /* if there is no current master make this fd it */
272         mutex_lock(&dev->struct_mutex);
273         if (!priv->minor->master) {
274                 /* create a new master */
275                 priv->minor->master = drm_master_create(priv->minor);
276                 if (!priv->minor->master) {
277                         ret = -ENOMEM;
278                         goto out_free;
279                 }
280
281                 priv->is_master = 1;
282                 /* take another reference for the copy in the local file priv */
283                 priv->master = drm_master_get(priv->minor->master);
284
285                 priv->authenticated = 1;
286
287                 mutex_unlock(&dev->struct_mutex);
288                 if (dev->driver->master_create) {
289                         ret = dev->driver->master_create(dev, priv->master);
290                         if (ret) {
291                                 mutex_lock(&dev->struct_mutex);
292                                 /* drop both references if this fails */
293                                 drm_master_put(&priv->minor->master);
294                                 drm_master_put(&priv->master);
295                                 mutex_unlock(&dev->struct_mutex);
296                                 goto out_free;
297                         }
298                 }
299         } else {
300                 /* get a reference to the master */
301                 priv->master = drm_master_get(priv->minor->master);
302                 mutex_unlock(&dev->struct_mutex);
303         }
304
305         mutex_lock(&dev->struct_mutex);
306         list_add(&priv->lhead, &dev->filelist);
307         mutex_unlock(&dev->struct_mutex);
308
309 #ifdef __alpha__
310         /*
311          * Default the hose
312          */
313         if (!dev->hose) {
314                 struct pci_dev *pci_dev;
315                 pci_dev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, NULL);
316                 if (pci_dev) {
317                         dev->hose = pci_dev->sysdata;
318                         pci_dev_put(pci_dev);
319                 }
320                 if (!dev->hose) {
321                         struct pci_bus *b = pci_bus_b(pci_root_buses.next);
322                         if (b)
323                                 dev->hose = b->sysdata;
324                 }
325         }
326 #endif
327
328         return 0;
329       out_free:
330         drm_free(priv, sizeof(*priv), DRM_MEM_FILES);
331         filp->private_data = NULL;
332         return ret;
333 }
334
335 /** No-op. */
336 int drm_fasync(int fd, struct file *filp, int on)
337 {
338         struct drm_file *priv = filp->private_data;
339         struct drm_device *dev = priv->minor->dev;
340         int retcode;
341
342         DRM_DEBUG("fd = %d, device = 0x%lx\n", fd,
343                   (long)old_encode_dev(priv->minor->device));
344         retcode = fasync_helper(fd, filp, on, &dev->buf_async);
345         if (retcode < 0)
346                 return retcode;
347         return 0;
348 }
349 EXPORT_SYMBOL(drm_fasync);
350
351 /*
352  * Reclaim locked buffers; note that this may be a bad idea if the current
353  * context doesn't have the hw lock...
354  */
355 static void drm_reclaim_locked_buffers(struct drm_device *dev, struct file *f)
356 {
357         struct drm_file *file_priv = f->private_data;
358
359         if (drm_i_have_hw_lock(dev, file_priv)) {
360                 dev->driver->reclaim_buffers_locked(dev, file_priv);
361         } else {
362                 unsigned long _end = jiffies + 3 * DRM_HZ;
363                 int locked = 0;
364
365                 drm_idlelock_take(&file_priv->master->lock);
366
367                 /*
368                  * Wait for a while.
369                  */
370                 do {
371                         spin_lock_bh(&file_priv->master->lock.spinlock);
372                         locked = file_priv->master->lock.idle_has_lock;
373                         spin_unlock_bh(&file_priv->master->lock.spinlock);
374                         if (locked)
375                                 break;
376                         schedule();
377                 } while (!time_after_eq(jiffies, _end));
378
379                 if (!locked) {
380                         DRM_ERROR("reclaim_buffers_locked() deadlock. Please rework this\n"
381                                   "\tdriver to use reclaim_buffers_idlelocked() instead.\n"
382                                   "\tI will go on reclaiming the buffers anyway.\n");
383                 }
384
385                 dev->driver->reclaim_buffers_locked(dev, file_priv);
386                 drm_idlelock_release(&file_priv->master->lock);
387         }
388 }
389
390 static void drm_master_release(struct drm_device *dev, struct file *filp)
391 {
392         struct drm_file *file_priv = filp->private_data;
393
394         if (dev->driver->reclaim_buffers_locked &&
395             file_priv->master->lock.hw_lock)
396                 drm_reclaim_locked_buffers(dev, filp);
397
398         if (dev->driver->reclaim_buffers_idlelocked &&
399             file_priv->master->lock.hw_lock) {
400                 drm_idlelock_take(&file_priv->master->lock);
401                 dev->driver->reclaim_buffers_idlelocked(dev, file_priv);
402                 drm_idlelock_release(&file_priv->master->lock);
403         }
404
405
406         if (drm_i_have_hw_lock(dev, file_priv)) {
407                 DRM_DEBUG("File %p released, freeing lock for context %d\n",
408                           filp, _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
409                 drm_lock_free(&file_priv->master->lock,
410                               _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
411         }
412
413         if (drm_core_check_feature(dev, DRIVER_HAVE_DMA) &&
414             !dev->driver->reclaim_buffers_locked) {
415                 dev->driver->reclaim_buffers(dev, file_priv);
416         }
417 }
418
419 /**
420  * Release file.
421  *
422  * \param inode device inode
423  * \param file_priv DRM file private.
424  * \return zero on success or a negative number on failure.
425  *
426  * If the hardware lock is held then free it, and take it again for the kernel
427  * context since it's necessary to reclaim buffers. Unlink the file private
428  * data from its list and free it. Decreases the open count and if it reaches
429  * zero calls drm_lastclose().
430  */
431 int drm_release(struct inode *inode, struct file *filp)
432 {
433         struct drm_file *file_priv = filp->private_data;
434         struct drm_device *dev = file_priv->minor->dev;
435         int retcode = 0;
436
437         lock_kernel();
438
439         DRM_DEBUG("open_count = %d\n", dev->open_count);
440
441         if (dev->driver->preclose)
442                 dev->driver->preclose(dev, file_priv);
443
444         /* ========================================================
445          * Begin inline drm_release
446          */
447
448         DRM_DEBUG("pid = %d, device = 0x%lx, open_count = %d\n",
449                   task_pid_nr(current),
450                   (long)old_encode_dev(file_priv->minor->device),
451                   dev->open_count);
452
453         /* if the master has gone away we can't do anything with the lock */
454         if (file_priv->minor->master)
455                 drm_master_release(dev, filp);
456
457         if (dev->driver->driver_features & DRIVER_GEM)
458                 drm_gem_release(dev, file_priv);
459
460         mutex_lock(&dev->ctxlist_mutex);
461         if (!list_empty(&dev->ctxlist)) {
462                 struct drm_ctx_list *pos, *n;
463
464                 list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
465                         if (pos->tag == file_priv &&
466                             pos->handle != DRM_KERNEL_CONTEXT) {
467                                 if (dev->driver->context_dtor)
468                                         dev->driver->context_dtor(dev,
469                                                                   pos->handle);
470
471                                 drm_ctxbitmap_free(dev, pos->handle);
472
473                                 list_del(&pos->head);
474                                 drm_free(pos, sizeof(*pos), DRM_MEM_CTXLIST);
475                                 --dev->ctx_count;
476                         }
477                 }
478         }
479         mutex_unlock(&dev->ctxlist_mutex);
480
481         mutex_lock(&dev->struct_mutex);
482
483         if (file_priv->is_master) {
484                 struct drm_file *temp;
485                 list_for_each_entry(temp, &dev->filelist, lhead) {
486                         if ((temp->master == file_priv->master) &&
487                             (temp != file_priv))
488                                 temp->authenticated = 0;
489                 }
490
491                 if (file_priv->minor->master == file_priv->master) {
492                         /* drop the reference held my the minor */
493                         drm_master_put(&file_priv->minor->master);
494                 }
495         }
496
497         /* drop the reference held my the file priv */
498         drm_master_put(&file_priv->master);
499         file_priv->is_master = 0;
500         list_del(&file_priv->lhead);
501         mutex_unlock(&dev->struct_mutex);
502
503         if (dev->driver->postclose)
504                 dev->driver->postclose(dev, file_priv);
505         drm_free(file_priv, sizeof(*file_priv), DRM_MEM_FILES);
506
507         /* ========================================================
508          * End inline drm_release
509          */
510
511         atomic_inc(&dev->counts[_DRM_STAT_CLOSES]);
512         spin_lock(&dev->count_lock);
513         if (!--dev->open_count) {
514                 if (atomic_read(&dev->ioctl_count)) {
515                         DRM_ERROR("Device busy: %d\n",
516                                   atomic_read(&dev->ioctl_count));
517                         spin_unlock(&dev->count_lock);
518                         unlock_kernel();
519                         return -EBUSY;
520                 }
521                 spin_unlock(&dev->count_lock);
522                 unlock_kernel();
523                 return drm_lastclose(dev);
524         }
525         spin_unlock(&dev->count_lock);
526
527         unlock_kernel();
528
529         return retcode;
530 }
531 EXPORT_SYMBOL(drm_release);
532
533 /** No-op. */
534 unsigned int drm_poll(struct file *filp, struct poll_table_struct *wait)
535 {
536         return 0;
537 }
538 EXPORT_SYMBOL(drm_poll);