Branch data Line data Source code
1 : : // SPDX-License-Identifier: GPL-2.0-only
2 : : /*
3 : : * Framework for buffer objects that can be shared across devices/subsystems.
4 : : *
5 : : * Copyright(C) 2011 Linaro Limited. All rights reserved.
6 : : * Author: Sumit Semwal <sumit.semwal@ti.com>
7 : : *
8 : : * Many thanks to linaro-mm-sig list, and specially
9 : : * Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and
10 : : * Daniel Vetter <daniel@ffwll.ch> for their support in creation and
11 : : * refining of this idea.
12 : : */
13 : :
14 : : #include <linux/fs.h>
15 : : #include <linux/slab.h>
16 : : #include <linux/dma-buf.h>
17 : : #include <linux/dma-fence.h>
18 : : #include <linux/anon_inodes.h>
19 : : #include <linux/export.h>
20 : : #include <linux/debugfs.h>
21 : : #include <linux/module.h>
22 : : #include <linux/seq_file.h>
23 : : #include <linux/poll.h>
24 : : #include <linux/dma-resv.h>
25 : : #include <linux/mm.h>
26 : : #include <linux/mount.h>
27 : : #include <linux/pseudo_fs.h>
28 : :
29 : : #include <uapi/linux/dma-buf.h>
30 : : #include <uapi/linux/magic.h>
31 : :
32 : : static inline int is_dma_buf_file(struct file *);
33 : :
34 : : struct dma_buf_list {
35 : : struct list_head head;
36 : : struct mutex lock;
37 : : };
38 : :
39 : : static struct dma_buf_list db_list;
40 : :
41 : 0 : static char *dmabuffs_dname(struct dentry *dentry, char *buffer, int buflen)
42 : : {
43 : : struct dma_buf *dmabuf;
44 : : char name[DMA_BUF_NAME_LEN];
45 : : size_t ret = 0;
46 : :
47 : 0 : dmabuf = dentry->d_fsdata;
48 : : spin_lock(&dmabuf->name_lock);
49 : 0 : if (dmabuf->name)
50 : 0 : ret = strlcpy(name, dmabuf->name, DMA_BUF_NAME_LEN);
51 : : spin_unlock(&dmabuf->name_lock);
52 : :
53 : 0 : return dynamic_dname(dentry, buffer, buflen, "/%s:%s",
54 : : dentry->d_name.name, ret > 0 ? name : "");
55 : : }
56 : :
57 : 0 : static void dma_buf_release(struct dentry *dentry)
58 : : {
59 : : struct dma_buf *dmabuf;
60 : :
61 : 0 : dmabuf = dentry->d_fsdata;
62 : :
63 : 0 : BUG_ON(dmabuf->vmapping_counter);
64 : :
65 : : /*
66 : : * Any fences that a dma-buf poll can wait on should be signaled
67 : : * before releasing dma-buf. This is the responsibility of each
68 : : * driver that uses the reservation objects.
69 : : *
70 : : * If you hit this BUG() it means someone dropped their ref to the
71 : : * dma-buf while still having pending operation to the buffer.
72 : : */
73 : 0 : BUG_ON(dmabuf->cb_shared.active || dmabuf->cb_excl.active);
74 : :
75 : 0 : dmabuf->ops->release(dmabuf);
76 : :
77 : 0 : mutex_lock(&db_list.lock);
78 : : list_del(&dmabuf->list_node);
79 : 0 : mutex_unlock(&db_list.lock);
80 : :
81 : 0 : if (dmabuf->resv == (struct dma_resv *)&dmabuf[1])
82 : 0 : dma_resv_fini(dmabuf->resv);
83 : :
84 : 0 : module_put(dmabuf->owner);
85 : 0 : kfree(dmabuf->name);
86 : 0 : kfree(dmabuf);
87 : 0 : }
88 : :
89 : : static const struct dentry_operations dma_buf_dentry_ops = {
90 : : .d_dname = dmabuffs_dname,
91 : : .d_release = dma_buf_release,
92 : : };
93 : :
94 : : static struct vfsmount *dma_buf_mnt;
95 : :
96 : 3 : static int dma_buf_fs_init_context(struct fs_context *fc)
97 : : {
98 : : struct pseudo_fs_context *ctx;
99 : :
100 : 3 : ctx = init_pseudo(fc, DMA_BUF_MAGIC);
101 : 3 : if (!ctx)
102 : : return -ENOMEM;
103 : 3 : ctx->dops = &dma_buf_dentry_ops;
104 : 3 : return 0;
105 : : }
106 : :
107 : : static struct file_system_type dma_buf_fs_type = {
108 : : .name = "dmabuf",
109 : : .init_fs_context = dma_buf_fs_init_context,
110 : : .kill_sb = kill_anon_super,
111 : : };
112 : :
113 : 0 : static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
114 : : {
115 : : struct dma_buf *dmabuf;
116 : :
117 : 0 : if (!is_dma_buf_file(file))
118 : : return -EINVAL;
119 : :
120 : 0 : dmabuf = file->private_data;
121 : :
122 : : /* check if buffer supports mmap */
123 : 0 : if (!dmabuf->ops->mmap)
124 : : return -EINVAL;
125 : :
126 : : /* check for overflowing the buffer's size */
127 : 0 : if (vma->vm_pgoff + vma_pages(vma) >
128 : 0 : dmabuf->size >> PAGE_SHIFT)
129 : : return -EINVAL;
130 : :
131 : 0 : return dmabuf->ops->mmap(dmabuf, vma);
132 : : }
133 : :
134 : 0 : static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
135 : : {
136 : : struct dma_buf *dmabuf;
137 : : loff_t base;
138 : :
139 : 0 : if (!is_dma_buf_file(file))
140 : : return -EBADF;
141 : :
142 : 0 : dmabuf = file->private_data;
143 : :
144 : : /* only support discovering the end of the buffer,
145 : : but also allow SEEK_SET to maintain the idiomatic
146 : : SEEK_END(0), SEEK_CUR(0) pattern */
147 : 0 : if (whence == SEEK_END)
148 : 0 : base = dmabuf->size;
149 : 0 : else if (whence == SEEK_SET)
150 : : base = 0;
151 : : else
152 : : return -EINVAL;
153 : :
154 : 0 : if (offset != 0)
155 : : return -EINVAL;
156 : :
157 : 0 : return base + offset;
158 : : }
159 : :
160 : : /**
161 : : * DOC: fence polling
162 : : *
163 : : * To support cross-device and cross-driver synchronization of buffer access
164 : : * implicit fences (represented internally in the kernel with &struct fence) can
165 : : * be attached to a &dma_buf. The glue for that and a few related things are
166 : : * provided in the &dma_resv structure.
167 : : *
168 : : * Userspace can query the state of these implicitly tracked fences using poll()
169 : : * and related system calls:
170 : : *
171 : : * - Checking for EPOLLIN, i.e. read access, can be use to query the state of the
172 : : * most recent write or exclusive fence.
173 : : *
174 : : * - Checking for EPOLLOUT, i.e. write access, can be used to query the state of
175 : : * all attached fences, shared and exclusive ones.
176 : : *
177 : : * Note that this only signals the completion of the respective fences, i.e. the
178 : : * DMA transfers are complete. Cache flushing and any other necessary
179 : : * preparations before CPU access can begin still need to happen.
180 : : */
181 : :
182 : 0 : static void dma_buf_poll_cb(struct dma_fence *fence, struct dma_fence_cb *cb)
183 : : {
184 : : struct dma_buf_poll_cb_t *dcb = (struct dma_buf_poll_cb_t *)cb;
185 : : unsigned long flags;
186 : :
187 : 0 : spin_lock_irqsave(&dcb->poll->lock, flags);
188 : 0 : wake_up_locked_poll(dcb->poll, dcb->active);
189 : 0 : dcb->active = 0;
190 : 0 : spin_unlock_irqrestore(&dcb->poll->lock, flags);
191 : 0 : }
192 : :
193 : 0 : static __poll_t dma_buf_poll(struct file *file, poll_table *poll)
194 : : {
195 : : struct dma_buf *dmabuf;
196 : : struct dma_resv *resv;
197 : : struct dma_resv_list *fobj;
198 : : struct dma_fence *fence_excl;
199 : : __poll_t events;
200 : : unsigned shared_count, seq;
201 : :
202 : 0 : dmabuf = file->private_data;
203 : 0 : if (!dmabuf || !dmabuf->resv)
204 : : return EPOLLERR;
205 : :
206 : : resv = dmabuf->resv;
207 : :
208 : 0 : poll_wait(file, &dmabuf->poll, poll);
209 : :
210 : 0 : events = poll_requested_events(poll) & (EPOLLIN | EPOLLOUT);
211 : 0 : if (!events)
212 : : return 0;
213 : :
214 : : retry:
215 : : seq = read_seqcount_begin(&resv->seq);
216 : : rcu_read_lock();
217 : :
218 : 0 : fobj = rcu_dereference(resv->fence);
219 : 0 : if (fobj)
220 : 0 : shared_count = fobj->shared_count;
221 : : else
222 : : shared_count = 0;
223 : 0 : fence_excl = rcu_dereference(resv->fence_excl);
224 : 0 : if (read_seqcount_retry(&resv->seq, seq)) {
225 : : rcu_read_unlock();
226 : : goto retry;
227 : : }
228 : :
229 : 0 : if (fence_excl && (!(events & EPOLLOUT) || shared_count == 0)) {
230 : : struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_excl;
231 : : __poll_t pevents = EPOLLIN;
232 : :
233 : 0 : if (shared_count == 0)
234 : : pevents |= EPOLLOUT;
235 : :
236 : : spin_lock_irq(&dmabuf->poll.lock);
237 : 0 : if (dcb->active) {
238 : 0 : dcb->active |= pevents;
239 : 0 : events &= ~pevents;
240 : : } else
241 : 0 : dcb->active = pevents;
242 : : spin_unlock_irq(&dmabuf->poll.lock);
243 : :
244 : 0 : if (events & pevents) {
245 : 0 : if (!dma_fence_get_rcu(fence_excl)) {
246 : : /* force a recheck */
247 : 0 : events &= ~pevents;
248 : 0 : dma_buf_poll_cb(NULL, &dcb->cb);
249 : 0 : } else if (!dma_fence_add_callback(fence_excl, &dcb->cb,
250 : : dma_buf_poll_cb)) {
251 : 0 : events &= ~pevents;
252 : : dma_fence_put(fence_excl);
253 : : } else {
254 : : /*
255 : : * No callback queued, wake up any additional
256 : : * waiters.
257 : : */
258 : : dma_fence_put(fence_excl);
259 : 0 : dma_buf_poll_cb(NULL, &dcb->cb);
260 : : }
261 : : }
262 : : }
263 : :
264 : 0 : if ((events & EPOLLOUT) && shared_count > 0) {
265 : : struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_shared;
266 : : int i;
267 : :
268 : : /* Only queue a new callback if no event has fired yet */
269 : : spin_lock_irq(&dmabuf->poll.lock);
270 : 0 : if (dcb->active)
271 : 0 : events &= ~EPOLLOUT;
272 : : else
273 : 0 : dcb->active = EPOLLOUT;
274 : : spin_unlock_irq(&dmabuf->poll.lock);
275 : :
276 : 0 : if (!(events & EPOLLOUT))
277 : : goto out;
278 : :
279 : 0 : for (i = 0; i < shared_count; ++i) {
280 : 0 : struct dma_fence *fence = rcu_dereference(fobj->shared[i]);
281 : :
282 : 0 : if (!dma_fence_get_rcu(fence)) {
283 : : /*
284 : : * fence refcount dropped to zero, this means
285 : : * that fobj has been freed
286 : : *
287 : : * call dma_buf_poll_cb and force a recheck!
288 : : */
289 : 0 : events &= ~EPOLLOUT;
290 : 0 : dma_buf_poll_cb(NULL, &dcb->cb);
291 : 0 : break;
292 : : }
293 : 0 : if (!dma_fence_add_callback(fence, &dcb->cb,
294 : : dma_buf_poll_cb)) {
295 : : dma_fence_put(fence);
296 : 0 : events &= ~EPOLLOUT;
297 : 0 : break;
298 : : }
299 : : dma_fence_put(fence);
300 : : }
301 : :
302 : : /* No callback queued, wake up any additional waiters. */
303 : 0 : if (i == shared_count)
304 : 0 : dma_buf_poll_cb(NULL, &dcb->cb);
305 : : }
306 : :
307 : : out:
308 : : rcu_read_unlock();
309 : 0 : return events;
310 : : }
311 : :
312 : : /**
313 : : * dma_buf_set_name - Set a name to a specific dma_buf to track the usage.
314 : : * The name of the dma-buf buffer can only be set when the dma-buf is not
315 : : * attached to any devices. It could theoritically support changing the
316 : : * name of the dma-buf if the same piece of memory is used for multiple
317 : : * purpose between different devices.
318 : : *
319 : : * @dmabuf [in] dmabuf buffer that will be renamed.
320 : : * @buf: [in] A piece of userspace memory that contains the name of
321 : : * the dma-buf.
322 : : *
323 : : * Returns 0 on success. If the dma-buf buffer is already attached to
324 : : * devices, return -EBUSY.
325 : : *
326 : : */
327 : 0 : static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf)
328 : : {
329 : 0 : char *name = strndup_user(buf, DMA_BUF_NAME_LEN);
330 : : long ret = 0;
331 : :
332 : 0 : if (IS_ERR(name))
333 : 0 : return PTR_ERR(name);
334 : :
335 : 0 : mutex_lock(&dmabuf->lock);
336 : 0 : if (!list_empty(&dmabuf->attachments)) {
337 : : ret = -EBUSY;
338 : 0 : kfree(name);
339 : 0 : goto out_unlock;
340 : : }
341 : : spin_lock(&dmabuf->name_lock);
342 : 0 : kfree(dmabuf->name);
343 : 0 : dmabuf->name = name;
344 : : spin_unlock(&dmabuf->name_lock);
345 : :
346 : : out_unlock:
347 : 0 : mutex_unlock(&dmabuf->lock);
348 : 0 : return ret;
349 : : }
350 : :
351 : 0 : static long dma_buf_ioctl(struct file *file,
352 : : unsigned int cmd, unsigned long arg)
353 : : {
354 : : struct dma_buf *dmabuf;
355 : : struct dma_buf_sync sync;
356 : : enum dma_data_direction direction;
357 : : int ret;
358 : :
359 : 0 : dmabuf = file->private_data;
360 : :
361 : 0 : switch (cmd) {
362 : : case DMA_BUF_IOCTL_SYNC:
363 : 0 : if (copy_from_user(&sync, (void __user *) arg, sizeof(sync)))
364 : : return -EFAULT;
365 : :
366 : 0 : if (sync.flags & ~DMA_BUF_SYNC_VALID_FLAGS_MASK)
367 : : return -EINVAL;
368 : :
369 : 0 : switch (sync.flags & DMA_BUF_SYNC_RW) {
370 : : case DMA_BUF_SYNC_READ:
371 : : direction = DMA_FROM_DEVICE;
372 : : break;
373 : : case DMA_BUF_SYNC_WRITE:
374 : : direction = DMA_TO_DEVICE;
375 : 0 : break;
376 : : case DMA_BUF_SYNC_RW:
377 : : direction = DMA_BIDIRECTIONAL;
378 : 0 : break;
379 : : default:
380 : : return -EINVAL;
381 : : }
382 : :
383 : 0 : if (sync.flags & DMA_BUF_SYNC_END)
384 : 0 : ret = dma_buf_end_cpu_access(dmabuf, direction);
385 : : else
386 : 0 : ret = dma_buf_begin_cpu_access(dmabuf, direction);
387 : :
388 : 0 : return ret;
389 : :
390 : : case DMA_BUF_SET_NAME_A:
391 : : case DMA_BUF_SET_NAME_B:
392 : 0 : return dma_buf_set_name(dmabuf, (const char __user *)arg);
393 : :
394 : : default:
395 : : return -ENOTTY;
396 : : }
397 : : }
398 : :
399 : 0 : static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file)
400 : : {
401 : 0 : struct dma_buf *dmabuf = file->private_data;
402 : :
403 : 0 : seq_printf(m, "size:\t%zu\n", dmabuf->size);
404 : : /* Don't count the temporary reference taken inside procfs seq_show */
405 : 0 : seq_printf(m, "count:\t%ld\n", file_count(dmabuf->file) - 1);
406 : 0 : seq_printf(m, "exp_name:\t%s\n", dmabuf->exp_name);
407 : : spin_lock(&dmabuf->name_lock);
408 : 0 : if (dmabuf->name)
409 : 0 : seq_printf(m, "name:\t%s\n", dmabuf->name);
410 : : spin_unlock(&dmabuf->name_lock);
411 : 0 : }
412 : :
413 : : static const struct file_operations dma_buf_fops = {
414 : : .mmap = dma_buf_mmap_internal,
415 : : .llseek = dma_buf_llseek,
416 : : .poll = dma_buf_poll,
417 : : .unlocked_ioctl = dma_buf_ioctl,
418 : : #ifdef CONFIG_COMPAT
419 : : .compat_ioctl = dma_buf_ioctl,
420 : : #endif
421 : : .show_fdinfo = dma_buf_show_fdinfo,
422 : : };
423 : :
424 : : /*
425 : : * is_dma_buf_file - Check if struct file* is associated with dma_buf
426 : : */
427 : : static inline int is_dma_buf_file(struct file *file)
428 : : {
429 : 0 : return file->f_op == &dma_buf_fops;
430 : : }
431 : :
432 : 0 : static struct file *dma_buf_getfile(struct dma_buf *dmabuf, int flags)
433 : : {
434 : : struct file *file;
435 : 0 : struct inode *inode = alloc_anon_inode(dma_buf_mnt->mnt_sb);
436 : :
437 : 0 : if (IS_ERR(inode))
438 : : return ERR_CAST(inode);
439 : :
440 : 0 : inode->i_size = dmabuf->size;
441 : 0 : inode_set_bytes(inode, dmabuf->size);
442 : :
443 : 0 : file = alloc_file_pseudo(inode, dma_buf_mnt, "dmabuf",
444 : : flags, &dma_buf_fops);
445 : 0 : if (IS_ERR(file))
446 : : goto err_alloc_file;
447 : 0 : file->f_flags = flags & (O_ACCMODE | O_NONBLOCK);
448 : 0 : file->private_data = dmabuf;
449 : 0 : file->f_path.dentry->d_fsdata = dmabuf;
450 : :
451 : 0 : return file;
452 : :
453 : : err_alloc_file:
454 : 0 : iput(inode);
455 : 0 : return file;
456 : : }
457 : :
458 : : /**
459 : : * DOC: dma buf device access
460 : : *
461 : : * For device DMA access to a shared DMA buffer the usual sequence of operations
462 : : * is fairly simple:
463 : : *
464 : : * 1. The exporter defines his exporter instance using
465 : : * DEFINE_DMA_BUF_EXPORT_INFO() and calls dma_buf_export() to wrap a private
466 : : * buffer object into a &dma_buf. It then exports that &dma_buf to userspace
467 : : * as a file descriptor by calling dma_buf_fd().
468 : : *
469 : : * 2. Userspace passes this file-descriptors to all drivers it wants this buffer
470 : : * to share with: First the filedescriptor is converted to a &dma_buf using
471 : : * dma_buf_get(). Then the buffer is attached to the device using
472 : : * dma_buf_attach().
473 : : *
474 : : * Up to this stage the exporter is still free to migrate or reallocate the
475 : : * backing storage.
476 : : *
477 : : * 3. Once the buffer is attached to all devices userspace can initiate DMA
478 : : * access to the shared buffer. In the kernel this is done by calling
479 : : * dma_buf_map_attachment() and dma_buf_unmap_attachment().
480 : : *
481 : : * 4. Once a driver is done with a shared buffer it needs to call
482 : : * dma_buf_detach() (after cleaning up any mappings) and then release the
483 : : * reference acquired with dma_buf_get by calling dma_buf_put().
484 : : *
485 : : * For the detailed semantics exporters are expected to implement see
486 : : * &dma_buf_ops.
487 : : */
488 : :
489 : : /**
490 : : * dma_buf_export - Creates a new dma_buf, and associates an anon file
491 : : * with this buffer, so it can be exported.
492 : : * Also connect the allocator specific data and ops to the buffer.
493 : : * Additionally, provide a name string for exporter; useful in debugging.
494 : : *
495 : : * @exp_info: [in] holds all the export related information provided
496 : : * by the exporter. see &struct dma_buf_export_info
497 : : * for further details.
498 : : *
499 : : * Returns, on success, a newly created dma_buf object, which wraps the
500 : : * supplied private data and operations for dma_buf_ops. On either missing
501 : : * ops, or error in allocating struct dma_buf, will return negative error.
502 : : *
503 : : * For most cases the easiest way to create @exp_info is through the
504 : : * %DEFINE_DMA_BUF_EXPORT_INFO macro.
505 : : */
506 : 0 : struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
507 : : {
508 : : struct dma_buf *dmabuf;
509 : 0 : struct dma_resv *resv = exp_info->resv;
510 : : struct file *file;
511 : : size_t alloc_size = sizeof(struct dma_buf);
512 : : int ret;
513 : :
514 : 0 : if (!exp_info->resv)
515 : : alloc_size += sizeof(struct dma_resv);
516 : : else
517 : : /* prevent &dma_buf[1] == dma_buf->resv */
518 : : alloc_size += 1;
519 : :
520 : 0 : if (WARN_ON(!exp_info->priv
521 : : || !exp_info->ops
522 : : || !exp_info->ops->map_dma_buf
523 : : || !exp_info->ops->unmap_dma_buf
524 : : || !exp_info->ops->release)) {
525 : : return ERR_PTR(-EINVAL);
526 : : }
527 : :
528 : 0 : if (!try_module_get(exp_info->owner))
529 : : return ERR_PTR(-ENOENT);
530 : :
531 : 0 : dmabuf = kzalloc(alloc_size, GFP_KERNEL);
532 : 0 : if (!dmabuf) {
533 : : ret = -ENOMEM;
534 : : goto err_module;
535 : : }
536 : :
537 : 0 : dmabuf->priv = exp_info->priv;
538 : 0 : dmabuf->ops = exp_info->ops;
539 : 0 : dmabuf->size = exp_info->size;
540 : 0 : dmabuf->exp_name = exp_info->exp_name;
541 : 0 : dmabuf->owner = exp_info->owner;
542 : 0 : spin_lock_init(&dmabuf->name_lock);
543 : 0 : init_waitqueue_head(&dmabuf->poll);
544 : 0 : dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll;
545 : 0 : dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0;
546 : :
547 : 0 : if (!resv) {
548 : 0 : resv = (struct dma_resv *)&dmabuf[1];
549 : 0 : dma_resv_init(resv);
550 : : }
551 : 0 : dmabuf->resv = resv;
552 : :
553 : 0 : file = dma_buf_getfile(dmabuf, exp_info->flags);
554 : 0 : if (IS_ERR(file)) {
555 : : ret = PTR_ERR(file);
556 : : goto err_dmabuf;
557 : : }
558 : :
559 : 0 : file->f_mode |= FMODE_LSEEK;
560 : 0 : dmabuf->file = file;
561 : :
562 : 0 : mutex_init(&dmabuf->lock);
563 : 0 : INIT_LIST_HEAD(&dmabuf->attachments);
564 : :
565 : 0 : mutex_lock(&db_list.lock);
566 : 0 : list_add(&dmabuf->list_node, &db_list.head);
567 : 0 : mutex_unlock(&db_list.lock);
568 : :
569 : 0 : return dmabuf;
570 : :
571 : : err_dmabuf:
572 : 0 : kfree(dmabuf);
573 : : err_module:
574 : 0 : module_put(exp_info->owner);
575 : 0 : return ERR_PTR(ret);
576 : : }
577 : : EXPORT_SYMBOL_GPL(dma_buf_export);
578 : :
579 : : /**
580 : : * dma_buf_fd - returns a file descriptor for the given dma_buf
581 : : * @dmabuf: [in] pointer to dma_buf for which fd is required.
582 : : * @flags: [in] flags to give to fd
583 : : *
584 : : * On success, returns an associated 'fd'. Else, returns error.
585 : : */
586 : 0 : int dma_buf_fd(struct dma_buf *dmabuf, int flags)
587 : : {
588 : : int fd;
589 : :
590 : 0 : if (!dmabuf || !dmabuf->file)
591 : : return -EINVAL;
592 : :
593 : 0 : fd = get_unused_fd_flags(flags);
594 : 0 : if (fd < 0)
595 : : return fd;
596 : :
597 : 0 : fd_install(fd, dmabuf->file);
598 : :
599 : 0 : return fd;
600 : : }
601 : : EXPORT_SYMBOL_GPL(dma_buf_fd);
602 : :
603 : : /**
604 : : * dma_buf_get - returns the dma_buf structure related to an fd
605 : : * @fd: [in] fd associated with the dma_buf to be returned
606 : : *
607 : : * On success, returns the dma_buf structure associated with an fd; uses
608 : : * file's refcounting done by fget to increase refcount. returns ERR_PTR
609 : : * otherwise.
610 : : */
611 : 0 : struct dma_buf *dma_buf_get(int fd)
612 : : {
613 : : struct file *file;
614 : :
615 : 0 : file = fget(fd);
616 : :
617 : 0 : if (!file)
618 : : return ERR_PTR(-EBADF);
619 : :
620 : 0 : if (!is_dma_buf_file(file)) {
621 : 0 : fput(file);
622 : 0 : return ERR_PTR(-EINVAL);
623 : : }
624 : :
625 : 0 : return file->private_data;
626 : : }
627 : : EXPORT_SYMBOL_GPL(dma_buf_get);
628 : :
629 : : /**
630 : : * dma_buf_put - decreases refcount of the buffer
631 : : * @dmabuf: [in] buffer to reduce refcount of
632 : : *
633 : : * Uses file's refcounting done implicitly by fput().
634 : : *
635 : : * If, as a result of this call, the refcount becomes 0, the 'release' file
636 : : * operation related to this fd is called. It calls &dma_buf_ops.release vfunc
637 : : * in turn, and frees the memory allocated for dmabuf when exported.
638 : : */
639 : 0 : void dma_buf_put(struct dma_buf *dmabuf)
640 : : {
641 : 0 : if (WARN_ON(!dmabuf || !dmabuf->file))
642 : 0 : return;
643 : :
644 : 0 : fput(dmabuf->file);
645 : : }
646 : : EXPORT_SYMBOL_GPL(dma_buf_put);
647 : :
648 : : /**
649 : : * dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
650 : : * calls attach() of dma_buf_ops to allow device-specific attach functionality
651 : : * @dmabuf: [in] buffer to attach device to.
652 : : * @dev: [in] device to be attached.
653 : : *
654 : : * Returns struct dma_buf_attachment pointer for this attachment. Attachments
655 : : * must be cleaned up by calling dma_buf_detach().
656 : : *
657 : : * Returns:
658 : : *
659 : : * A pointer to newly created &dma_buf_attachment on success, or a negative
660 : : * error code wrapped into a pointer on failure.
661 : : *
662 : : * Note that this can fail if the backing storage of @dmabuf is in a place not
663 : : * accessible to @dev, and cannot be moved to a more suitable place. This is
664 : : * indicated with the error code -EBUSY.
665 : : */
666 : 0 : struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
667 : : struct device *dev)
668 : : {
669 : : struct dma_buf_attachment *attach;
670 : : int ret;
671 : :
672 : 0 : if (WARN_ON(!dmabuf || !dev))
673 : : return ERR_PTR(-EINVAL);
674 : :
675 : 0 : attach = kzalloc(sizeof(*attach), GFP_KERNEL);
676 : 0 : if (!attach)
677 : : return ERR_PTR(-ENOMEM);
678 : :
679 : 0 : attach->dev = dev;
680 : 0 : attach->dmabuf = dmabuf;
681 : :
682 : 0 : mutex_lock(&dmabuf->lock);
683 : :
684 : 0 : if (dmabuf->ops->attach) {
685 : 0 : ret = dmabuf->ops->attach(dmabuf, attach);
686 : 0 : if (ret)
687 : : goto err_attach;
688 : : }
689 : 0 : list_add(&attach->node, &dmabuf->attachments);
690 : :
691 : 0 : mutex_unlock(&dmabuf->lock);
692 : :
693 : 0 : return attach;
694 : :
695 : : err_attach:
696 : 0 : kfree(attach);
697 : 0 : mutex_unlock(&dmabuf->lock);
698 : 0 : return ERR_PTR(ret);
699 : : }
700 : : EXPORT_SYMBOL_GPL(dma_buf_attach);
701 : :
702 : : /**
703 : : * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
704 : : * optionally calls detach() of dma_buf_ops for device-specific detach
705 : : * @dmabuf: [in] buffer to detach from.
706 : : * @attach: [in] attachment to be detached; is free'd after this call.
707 : : *
708 : : * Clean up a device attachment obtained by calling dma_buf_attach().
709 : : */
710 : 0 : void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
711 : : {
712 : 0 : if (WARN_ON(!dmabuf || !attach))
713 : 0 : return;
714 : :
715 : 0 : if (attach->sgt)
716 : 0 : dmabuf->ops->unmap_dma_buf(attach, attach->sgt, attach->dir);
717 : :
718 : 0 : mutex_lock(&dmabuf->lock);
719 : : list_del(&attach->node);
720 : 0 : if (dmabuf->ops->detach)
721 : 0 : dmabuf->ops->detach(dmabuf, attach);
722 : :
723 : 0 : mutex_unlock(&dmabuf->lock);
724 : 0 : kfree(attach);
725 : : }
726 : : EXPORT_SYMBOL_GPL(dma_buf_detach);
727 : :
728 : : /**
729 : : * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
730 : : * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
731 : : * dma_buf_ops.
732 : : * @attach: [in] attachment whose scatterlist is to be returned
733 : : * @direction: [in] direction of DMA transfer
734 : : *
735 : : * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR
736 : : * on error. May return -EINTR if it is interrupted by a signal.
737 : : *
738 : : * A mapping must be unmapped by using dma_buf_unmap_attachment(). Note that
739 : : * the underlying backing storage is pinned for as long as a mapping exists,
740 : : * therefore users/importers should not hold onto a mapping for undue amounts of
741 : : * time.
742 : : */
743 : 0 : struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
744 : : enum dma_data_direction direction)
745 : : {
746 : : struct sg_table *sg_table;
747 : :
748 : 0 : might_sleep();
749 : :
750 : 0 : if (WARN_ON(!attach || !attach->dmabuf))
751 : : return ERR_PTR(-EINVAL);
752 : :
753 : 0 : if (attach->sgt) {
754 : : /*
755 : : * Two mappings with different directions for the same
756 : : * attachment are not allowed.
757 : : */
758 : 0 : if (attach->dir != direction &&
759 : : attach->dir != DMA_BIDIRECTIONAL)
760 : : return ERR_PTR(-EBUSY);
761 : :
762 : 0 : return attach->sgt;
763 : : }
764 : :
765 : 0 : sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
766 : 0 : if (!sg_table)
767 : : sg_table = ERR_PTR(-ENOMEM);
768 : :
769 : 0 : if (!IS_ERR(sg_table) && attach->dmabuf->ops->cache_sgt_mapping) {
770 : 0 : attach->sgt = sg_table;
771 : 0 : attach->dir = direction;
772 : : }
773 : :
774 : 0 : return sg_table;
775 : : }
776 : : EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
777 : :
778 : : /**
779 : : * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
780 : : * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
781 : : * dma_buf_ops.
782 : : * @attach: [in] attachment to unmap buffer from
783 : : * @sg_table: [in] scatterlist info of the buffer to unmap
784 : : * @direction: [in] direction of DMA transfer
785 : : *
786 : : * This unmaps a DMA mapping for @attached obtained by dma_buf_map_attachment().
787 : : */
788 : 0 : void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
789 : : struct sg_table *sg_table,
790 : : enum dma_data_direction direction)
791 : : {
792 : 0 : might_sleep();
793 : :
794 : 0 : if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
795 : : return;
796 : :
797 : 0 : if (attach->sgt == sg_table)
798 : : return;
799 : :
800 : 0 : attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction);
801 : : }
802 : : EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
803 : :
804 : : /**
805 : : * DOC: cpu access
806 : : *
807 : : * There are mutliple reasons for supporting CPU access to a dma buffer object:
808 : : *
809 : : * - Fallback operations in the kernel, for example when a device is connected
810 : : * over USB and the kernel needs to shuffle the data around first before
811 : : * sending it away. Cache coherency is handled by braketing any transactions
812 : : * with calls to dma_buf_begin_cpu_access() and dma_buf_end_cpu_access()
813 : : * access.
814 : : *
815 : : * To support dma_buf objects residing in highmem cpu access is page-based
816 : : * using an api similar to kmap. Accessing a dma_buf is done in aligned chunks
817 : : * of PAGE_SIZE size. Before accessing a chunk it needs to be mapped, which
818 : : * returns a pointer in kernel virtual address space. Afterwards the chunk
819 : : * needs to be unmapped again. There is no limit on how often a given chunk
820 : : * can be mapped and unmapped, i.e. the importer does not need to call
821 : : * begin_cpu_access again before mapping the same chunk again.
822 : : *
823 : : * Interfaces::
824 : : * void \*dma_buf_kmap(struct dma_buf \*, unsigned long);
825 : : * void dma_buf_kunmap(struct dma_buf \*, unsigned long, void \*);
826 : : *
827 : : * Implementing the functions is optional for exporters and for importers all
828 : : * the restrictions of using kmap apply.
829 : : *
830 : : * dma_buf kmap calls outside of the range specified in begin_cpu_access are
831 : : * undefined. If the range is not PAGE_SIZE aligned, kmap needs to succeed on
832 : : * the partial chunks at the beginning and end but may return stale or bogus
833 : : * data outside of the range (in these partial chunks).
834 : : *
835 : : * For some cases the overhead of kmap can be too high, a vmap interface
836 : : * is introduced. This interface should be used very carefully, as vmalloc
837 : : * space is a limited resources on many architectures.
838 : : *
839 : : * Interfaces::
840 : : * void \*dma_buf_vmap(struct dma_buf \*dmabuf)
841 : : * void dma_buf_vunmap(struct dma_buf \*dmabuf, void \*vaddr)
842 : : *
843 : : * The vmap call can fail if there is no vmap support in the exporter, or if
844 : : * it runs out of vmalloc space. Fallback to kmap should be implemented. Note
845 : : * that the dma-buf layer keeps a reference count for all vmap access and
846 : : * calls down into the exporter's vmap function only when no vmapping exists,
847 : : * and only unmaps it once. Protection against concurrent vmap/vunmap calls is
848 : : * provided by taking the dma_buf->lock mutex.
849 : : *
850 : : * - For full compatibility on the importer side with existing userspace
851 : : * interfaces, which might already support mmap'ing buffers. This is needed in
852 : : * many processing pipelines (e.g. feeding a software rendered image into a
853 : : * hardware pipeline, thumbnail creation, snapshots, ...). Also, Android's ION
854 : : * framework already supported this and for DMA buffer file descriptors to
855 : : * replace ION buffers mmap support was needed.
856 : : *
857 : : * There is no special interfaces, userspace simply calls mmap on the dma-buf
858 : : * fd. But like for CPU access there's a need to braket the actual access,
859 : : * which is handled by the ioctl (DMA_BUF_IOCTL_SYNC). Note that
860 : : * DMA_BUF_IOCTL_SYNC can fail with -EAGAIN or -EINTR, in which case it must
861 : : * be restarted.
862 : : *
863 : : * Some systems might need some sort of cache coherency management e.g. when
864 : : * CPU and GPU domains are being accessed through dma-buf at the same time.
865 : : * To circumvent this problem there are begin/end coherency markers, that
866 : : * forward directly to existing dma-buf device drivers vfunc hooks. Userspace
867 : : * can make use of those markers through the DMA_BUF_IOCTL_SYNC ioctl. The
868 : : * sequence would be used like following:
869 : : *
870 : : * - mmap dma-buf fd
871 : : * - for each drawing/upload cycle in CPU 1. SYNC_START ioctl, 2. read/write
872 : : * to mmap area 3. SYNC_END ioctl. This can be repeated as often as you
873 : : * want (with the new data being consumed by say the GPU or the scanout
874 : : * device)
875 : : * - munmap once you don't need the buffer any more
876 : : *
877 : : * For correctness and optimal performance, it is always required to use
878 : : * SYNC_START and SYNC_END before and after, respectively, when accessing the
879 : : * mapped address. Userspace cannot rely on coherent access, even when there
880 : : * are systems where it just works without calling these ioctls.
881 : : *
882 : : * - And as a CPU fallback in userspace processing pipelines.
883 : : *
884 : : * Similar to the motivation for kernel cpu access it is again important that
885 : : * the userspace code of a given importing subsystem can use the same
886 : : * interfaces with a imported dma-buf buffer object as with a native buffer
887 : : * object. This is especially important for drm where the userspace part of
888 : : * contemporary OpenGL, X, and other drivers is huge, and reworking them to
889 : : * use a different way to mmap a buffer rather invasive.
890 : : *
891 : : * The assumption in the current dma-buf interfaces is that redirecting the
892 : : * initial mmap is all that's needed. A survey of some of the existing
893 : : * subsystems shows that no driver seems to do any nefarious thing like
894 : : * syncing up with outstanding asynchronous processing on the device or
895 : : * allocating special resources at fault time. So hopefully this is good
896 : : * enough, since adding interfaces to intercept pagefaults and allow pte
897 : : * shootdowns would increase the complexity quite a bit.
898 : : *
899 : : * Interface::
900 : : * int dma_buf_mmap(struct dma_buf \*, struct vm_area_struct \*,
901 : : * unsigned long);
902 : : *
903 : : * If the importing subsystem simply provides a special-purpose mmap call to
904 : : * set up a mapping in userspace, calling do_mmap with dma_buf->file will
905 : : * equally achieve that for a dma-buf object.
906 : : */
907 : :
908 : 0 : static int __dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
909 : : enum dma_data_direction direction)
910 : : {
911 : 0 : bool write = (direction == DMA_BIDIRECTIONAL ||
912 : : direction == DMA_TO_DEVICE);
913 : 0 : struct dma_resv *resv = dmabuf->resv;
914 : : long ret;
915 : :
916 : : /* Wait on any implicit rendering fences */
917 : 0 : ret = dma_resv_wait_timeout_rcu(resv, write, true,
918 : : MAX_SCHEDULE_TIMEOUT);
919 : 0 : if (ret < 0)
920 : 0 : return ret;
921 : :
922 : : return 0;
923 : : }
924 : :
925 : : /**
926 : : * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
927 : : * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
928 : : * preparations. Coherency is only guaranteed in the specified range for the
929 : : * specified access direction.
930 : : * @dmabuf: [in] buffer to prepare cpu access for.
931 : : * @direction: [in] length of range for cpu access.
932 : : *
933 : : * After the cpu access is complete the caller should call
934 : : * dma_buf_end_cpu_access(). Only when cpu access is braketed by both calls is
935 : : * it guaranteed to be coherent with other DMA access.
936 : : *
937 : : * Can return negative error values, returns 0 on success.
938 : : */
939 : 0 : int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
940 : : enum dma_data_direction direction)
941 : : {
942 : : int ret = 0;
943 : :
944 : 0 : if (WARN_ON(!dmabuf))
945 : : return -EINVAL;
946 : :
947 : 0 : if (dmabuf->ops->begin_cpu_access)
948 : 0 : ret = dmabuf->ops->begin_cpu_access(dmabuf, direction);
949 : :
950 : : /* Ensure that all fences are waited upon - but we first allow
951 : : * the native handler the chance to do so more efficiently if it
952 : : * chooses. A double invocation here will be reasonably cheap no-op.
953 : : */
954 : 0 : if (ret == 0)
955 : 0 : ret = __dma_buf_begin_cpu_access(dmabuf, direction);
956 : :
957 : 0 : return ret;
958 : : }
959 : : EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access);
960 : :
961 : : /**
962 : : * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
963 : : * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
964 : : * actions. Coherency is only guaranteed in the specified range for the
965 : : * specified access direction.
966 : : * @dmabuf: [in] buffer to complete cpu access for.
967 : : * @direction: [in] length of range for cpu access.
968 : : *
969 : : * This terminates CPU access started with dma_buf_begin_cpu_access().
970 : : *
971 : : * Can return negative error values, returns 0 on success.
972 : : */
973 : 0 : int dma_buf_end_cpu_access(struct dma_buf *dmabuf,
974 : : enum dma_data_direction direction)
975 : : {
976 : : int ret = 0;
977 : :
978 : 0 : WARN_ON(!dmabuf);
979 : :
980 : 0 : if (dmabuf->ops->end_cpu_access)
981 : 0 : ret = dmabuf->ops->end_cpu_access(dmabuf, direction);
982 : :
983 : 0 : return ret;
984 : : }
985 : : EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
986 : :
987 : : /**
988 : : * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
989 : : * same restrictions as for kmap and friends apply.
990 : : * @dmabuf: [in] buffer to map page from.
991 : : * @page_num: [in] page in PAGE_SIZE units to map.
992 : : *
993 : : * This call must always succeed, any necessary preparations that might fail
994 : : * need to be done in begin_cpu_access.
995 : : */
996 : 0 : void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num)
997 : : {
998 : 0 : WARN_ON(!dmabuf);
999 : :
1000 : 0 : if (!dmabuf->ops->map)
1001 : : return NULL;
1002 : 0 : return dmabuf->ops->map(dmabuf, page_num);
1003 : : }
1004 : : EXPORT_SYMBOL_GPL(dma_buf_kmap);
1005 : :
1006 : : /**
1007 : : * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap.
1008 : : * @dmabuf: [in] buffer to unmap page from.
1009 : : * @page_num: [in] page in PAGE_SIZE units to unmap.
1010 : : * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap.
1011 : : *
1012 : : * This call must always succeed.
1013 : : */
1014 : 0 : void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num,
1015 : : void *vaddr)
1016 : : {
1017 : 0 : WARN_ON(!dmabuf);
1018 : :
1019 : 0 : if (dmabuf->ops->unmap)
1020 : 0 : dmabuf->ops->unmap(dmabuf, page_num, vaddr);
1021 : 0 : }
1022 : : EXPORT_SYMBOL_GPL(dma_buf_kunmap);
1023 : :
1024 : :
1025 : : /**
1026 : : * dma_buf_mmap - Setup up a userspace mmap with the given vma
1027 : : * @dmabuf: [in] buffer that should back the vma
1028 : : * @vma: [in] vma for the mmap
1029 : : * @pgoff: [in] offset in pages where this mmap should start within the
1030 : : * dma-buf buffer.
1031 : : *
1032 : : * This function adjusts the passed in vma so that it points at the file of the
1033 : : * dma_buf operation. It also adjusts the starting pgoff and does bounds
1034 : : * checking on the size of the vma. Then it calls the exporters mmap function to
1035 : : * set up the mapping.
1036 : : *
1037 : : * Can return negative error values, returns 0 on success.
1038 : : */
1039 : 0 : int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
1040 : : unsigned long pgoff)
1041 : : {
1042 : : struct file *oldfile;
1043 : : int ret;
1044 : :
1045 : 0 : if (WARN_ON(!dmabuf || !vma))
1046 : : return -EINVAL;
1047 : :
1048 : : /* check if buffer supports mmap */
1049 : 0 : if (!dmabuf->ops->mmap)
1050 : : return -EINVAL;
1051 : :
1052 : : /* check for offset overflow */
1053 : 0 : if (pgoff + vma_pages(vma) < pgoff)
1054 : : return -EOVERFLOW;
1055 : :
1056 : : /* check for overflowing the buffer's size */
1057 : 0 : if (pgoff + vma_pages(vma) >
1058 : 0 : dmabuf->size >> PAGE_SHIFT)
1059 : : return -EINVAL;
1060 : :
1061 : : /* readjust the vma */
1062 : 0 : get_file(dmabuf->file);
1063 : 0 : oldfile = vma->vm_file;
1064 : 0 : vma->vm_file = dmabuf->file;
1065 : 0 : vma->vm_pgoff = pgoff;
1066 : :
1067 : 0 : ret = dmabuf->ops->mmap(dmabuf, vma);
1068 : 0 : if (ret) {
1069 : : /* restore old parameters on failure */
1070 : 0 : vma->vm_file = oldfile;
1071 : 0 : fput(dmabuf->file);
1072 : : } else {
1073 : 0 : if (oldfile)
1074 : 0 : fput(oldfile);
1075 : : }
1076 : 0 : return ret;
1077 : :
1078 : : }
1079 : : EXPORT_SYMBOL_GPL(dma_buf_mmap);
1080 : :
1081 : : /**
1082 : : * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
1083 : : * address space. Same restrictions as for vmap and friends apply.
1084 : : * @dmabuf: [in] buffer to vmap
1085 : : *
1086 : : * This call may fail due to lack of virtual mapping address space.
1087 : : * These calls are optional in drivers. The intended use for them
1088 : : * is for mapping objects linear in kernel space for high use objects.
1089 : : * Please attempt to use kmap/kunmap before thinking about these interfaces.
1090 : : *
1091 : : * Returns NULL on error.
1092 : : */
1093 : 0 : void *dma_buf_vmap(struct dma_buf *dmabuf)
1094 : : {
1095 : : void *ptr;
1096 : :
1097 : 0 : if (WARN_ON(!dmabuf))
1098 : : return NULL;
1099 : :
1100 : 0 : if (!dmabuf->ops->vmap)
1101 : : return NULL;
1102 : :
1103 : 0 : mutex_lock(&dmabuf->lock);
1104 : 0 : if (dmabuf->vmapping_counter) {
1105 : 0 : dmabuf->vmapping_counter++;
1106 : 0 : BUG_ON(!dmabuf->vmap_ptr);
1107 : : ptr = dmabuf->vmap_ptr;
1108 : : goto out_unlock;
1109 : : }
1110 : :
1111 : 0 : BUG_ON(dmabuf->vmap_ptr);
1112 : :
1113 : 0 : ptr = dmabuf->ops->vmap(dmabuf);
1114 : 0 : if (WARN_ON_ONCE(IS_ERR(ptr)))
1115 : : ptr = NULL;
1116 : 0 : if (!ptr)
1117 : : goto out_unlock;
1118 : :
1119 : 0 : dmabuf->vmap_ptr = ptr;
1120 : 0 : dmabuf->vmapping_counter = 1;
1121 : :
1122 : : out_unlock:
1123 : 0 : mutex_unlock(&dmabuf->lock);
1124 : 0 : return ptr;
1125 : : }
1126 : : EXPORT_SYMBOL_GPL(dma_buf_vmap);
1127 : :
1128 : : /**
1129 : : * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
1130 : : * @dmabuf: [in] buffer to vunmap
1131 : : * @vaddr: [in] vmap to vunmap
1132 : : */
1133 : 0 : void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
1134 : : {
1135 : 0 : if (WARN_ON(!dmabuf))
1136 : 0 : return;
1137 : :
1138 : 0 : BUG_ON(!dmabuf->vmap_ptr);
1139 : 0 : BUG_ON(dmabuf->vmapping_counter == 0);
1140 : 0 : BUG_ON(dmabuf->vmap_ptr != vaddr);
1141 : :
1142 : 0 : mutex_lock(&dmabuf->lock);
1143 : 0 : if (--dmabuf->vmapping_counter == 0) {
1144 : 0 : if (dmabuf->ops->vunmap)
1145 : 0 : dmabuf->ops->vunmap(dmabuf, vaddr);
1146 : 0 : dmabuf->vmap_ptr = NULL;
1147 : : }
1148 : 0 : mutex_unlock(&dmabuf->lock);
1149 : : }
1150 : : EXPORT_SYMBOL_GPL(dma_buf_vunmap);
1151 : :
1152 : : #ifdef CONFIG_DEBUG_FS
1153 : 0 : static int dma_buf_debug_show(struct seq_file *s, void *unused)
1154 : : {
1155 : : int ret;
1156 : : struct dma_buf *buf_obj;
1157 : : struct dma_buf_attachment *attach_obj;
1158 : : struct dma_resv *robj;
1159 : : struct dma_resv_list *fobj;
1160 : : struct dma_fence *fence;
1161 : : unsigned seq;
1162 : : int count = 0, attach_count, shared_count, i;
1163 : : size_t size = 0;
1164 : :
1165 : 0 : ret = mutex_lock_interruptible(&db_list.lock);
1166 : :
1167 : 0 : if (ret)
1168 : : return ret;
1169 : :
1170 : 0 : seq_puts(s, "\nDma-buf Objects:\n");
1171 : 0 : seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\t%-8s\n",
1172 : : "size", "flags", "mode", "count", "ino");
1173 : :
1174 : 0 : list_for_each_entry(buf_obj, &db_list.head, list_node) {
1175 : 0 : ret = mutex_lock_interruptible(&buf_obj->lock);
1176 : :
1177 : 0 : if (ret) {
1178 : 0 : seq_puts(s,
1179 : : "\tERROR locking buffer object: skipping\n");
1180 : 0 : continue;
1181 : : }
1182 : :
1183 : 0 : seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\n",
1184 : : buf_obj->size,
1185 : 0 : buf_obj->file->f_flags, buf_obj->file->f_mode,
1186 : : file_count(buf_obj->file),
1187 : : buf_obj->exp_name,
1188 : : file_inode(buf_obj->file)->i_ino,
1189 : 0 : buf_obj->name ?: "");
1190 : :
1191 : 0 : robj = buf_obj->resv;
1192 : : while (true) {
1193 : : seq = read_seqcount_begin(&robj->seq);
1194 : : rcu_read_lock();
1195 : 0 : fobj = rcu_dereference(robj->fence);
1196 : 0 : shared_count = fobj ? fobj->shared_count : 0;
1197 : 0 : fence = rcu_dereference(robj->fence_excl);
1198 : 0 : if (!read_seqcount_retry(&robj->seq, seq))
1199 : : break;
1200 : : rcu_read_unlock();
1201 : : }
1202 : :
1203 : 0 : if (fence)
1204 : 0 : seq_printf(s, "\tExclusive fence: %s %s %ssignalled\n",
1205 : 0 : fence->ops->get_driver_name(fence),
1206 : 0 : fence->ops->get_timeline_name(fence),
1207 : 0 : dma_fence_is_signaled(fence) ? "" : "un");
1208 : 0 : for (i = 0; i < shared_count; i++) {
1209 : 0 : fence = rcu_dereference(fobj->shared[i]);
1210 : 0 : if (!dma_fence_get_rcu(fence))
1211 : 0 : continue;
1212 : 0 : seq_printf(s, "\tShared fence: %s %s %ssignalled\n",
1213 : 0 : fence->ops->get_driver_name(fence),
1214 : 0 : fence->ops->get_timeline_name(fence),
1215 : 0 : dma_fence_is_signaled(fence) ? "" : "un");
1216 : : dma_fence_put(fence);
1217 : : }
1218 : : rcu_read_unlock();
1219 : :
1220 : 0 : seq_puts(s, "\tAttached Devices:\n");
1221 : : attach_count = 0;
1222 : :
1223 : 0 : list_for_each_entry(attach_obj, &buf_obj->attachments, node) {
1224 : 0 : seq_printf(s, "\t%s\n", dev_name(attach_obj->dev));
1225 : 0 : attach_count++;
1226 : : }
1227 : :
1228 : 0 : seq_printf(s, "Total %d devices attached\n\n",
1229 : : attach_count);
1230 : :
1231 : 0 : count++;
1232 : 0 : size += buf_obj->size;
1233 : 0 : mutex_unlock(&buf_obj->lock);
1234 : : }
1235 : :
1236 : 0 : seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size);
1237 : :
1238 : 0 : mutex_unlock(&db_list.lock);
1239 : 0 : return 0;
1240 : : }
1241 : :
1242 : 0 : DEFINE_SHOW_ATTRIBUTE(dma_buf_debug);
1243 : :
1244 : : static struct dentry *dma_buf_debugfs_dir;
1245 : :
1246 : 3 : static int dma_buf_init_debugfs(void)
1247 : : {
1248 : : struct dentry *d;
1249 : : int err = 0;
1250 : :
1251 : 3 : d = debugfs_create_dir("dma_buf", NULL);
1252 : 3 : if (IS_ERR(d))
1253 : 0 : return PTR_ERR(d);
1254 : :
1255 : 3 : dma_buf_debugfs_dir = d;
1256 : :
1257 : 3 : d = debugfs_create_file("bufinfo", S_IRUGO, dma_buf_debugfs_dir,
1258 : : NULL, &dma_buf_debug_fops);
1259 : 3 : if (IS_ERR(d)) {
1260 : : pr_debug("dma_buf: debugfs: failed to create node bufinfo\n");
1261 : 0 : debugfs_remove_recursive(dma_buf_debugfs_dir);
1262 : 0 : dma_buf_debugfs_dir = NULL;
1263 : : err = PTR_ERR(d);
1264 : : }
1265 : :
1266 : 3 : return err;
1267 : : }
1268 : :
1269 : : static void dma_buf_uninit_debugfs(void)
1270 : : {
1271 : 0 : debugfs_remove_recursive(dma_buf_debugfs_dir);
1272 : : }
1273 : : #else
1274 : : static inline int dma_buf_init_debugfs(void)
1275 : : {
1276 : : return 0;
1277 : : }
1278 : : static inline void dma_buf_uninit_debugfs(void)
1279 : : {
1280 : : }
1281 : : #endif
1282 : :
1283 : 3 : static int __init dma_buf_init(void)
1284 : : {
1285 : 3 : dma_buf_mnt = kern_mount(&dma_buf_fs_type);
1286 : 3 : if (IS_ERR(dma_buf_mnt))
1287 : 0 : return PTR_ERR(dma_buf_mnt);
1288 : :
1289 : 3 : mutex_init(&db_list.lock);
1290 : : INIT_LIST_HEAD(&db_list.head);
1291 : 3 : dma_buf_init_debugfs();
1292 : 3 : return 0;
1293 : : }
1294 : : subsys_initcall(dma_buf_init);
1295 : :
1296 : 0 : static void __exit dma_buf_deinit(void)
1297 : : {
1298 : : dma_buf_uninit_debugfs();
1299 : 0 : kern_unmount(dma_buf_mnt);
1300 : 0 : }
1301 : : __exitcall(dma_buf_deinit);
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