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 : 0 : struct dma_buf *dmabuf;
44 : 0 : char name[DMA_BUF_NAME_LEN];
45 : 0 : size_t ret = 0;
46 : :
47 : 0 : dmabuf = dentry->d_fsdata;
48 : 0 : dma_resv_lock(dmabuf->resv, NULL);
49 [ # # ]: 0 : if (dmabuf->name)
50 : 0 : ret = strlcpy(name, dmabuf->name, DMA_BUF_NAME_LEN);
51 : 0 : dma_resv_unlock(dmabuf->resv);
52 : :
53 [ # # ]: 0 : return dynamic_dname(dentry, buffer, buflen, "/%s:%s",
54 : : dentry->d_name.name, ret > 0 ? name : "");
55 : : }
56 : :
57 : : static const struct dentry_operations dma_buf_dentry_ops = {
58 : : .d_dname = dmabuffs_dname,
59 : : };
60 : :
61 : : static struct vfsmount *dma_buf_mnt;
62 : :
63 : 28 : static int dma_buf_fs_init_context(struct fs_context *fc)
64 : : {
65 : 28 : struct pseudo_fs_context *ctx;
66 : :
67 : 28 : ctx = init_pseudo(fc, DMA_BUF_MAGIC);
68 [ + - ]: 28 : if (!ctx)
69 : : return -ENOMEM;
70 : 28 : ctx->dops = &dma_buf_dentry_ops;
71 : 28 : return 0;
72 : : }
73 : :
74 : : static struct file_system_type dma_buf_fs_type = {
75 : : .name = "dmabuf",
76 : : .init_fs_context = dma_buf_fs_init_context,
77 : : .kill_sb = kill_anon_super,
78 : : };
79 : :
80 : 0 : static int dma_buf_release(struct inode *inode, struct file *file)
81 : : {
82 : 0 : struct dma_buf *dmabuf;
83 : :
84 : 0 : if (!is_dma_buf_file(file))
85 : : return -EINVAL;
86 : :
87 : 0 : dmabuf = file->private_data;
88 : :
89 [ # # ]: 0 : BUG_ON(dmabuf->vmapping_counter);
90 : :
91 : : /*
92 : : * Any fences that a dma-buf poll can wait on should be signaled
93 : : * before releasing dma-buf. This is the responsibility of each
94 : : * driver that uses the reservation objects.
95 : : *
96 : : * If you hit this BUG() it means someone dropped their ref to the
97 : : * dma-buf while still having pending operation to the buffer.
98 : : */
99 [ # # # # ]: 0 : BUG_ON(dmabuf->cb_shared.active || dmabuf->cb_excl.active);
100 : :
101 : 0 : dmabuf->ops->release(dmabuf);
102 : :
103 : 0 : mutex_lock(&db_list.lock);
104 : 0 : list_del(&dmabuf->list_node);
105 : 0 : mutex_unlock(&db_list.lock);
106 : :
107 [ # # ]: 0 : if (dmabuf->resv == (struct dma_resv *)&dmabuf[1])
108 : 0 : dma_resv_fini(dmabuf->resv);
109 : :
110 : 0 : module_put(dmabuf->owner);
111 : 0 : kfree(dmabuf->name);
112 : 0 : kfree(dmabuf);
113 : 0 : return 0;
114 : : }
115 : :
116 : 0 : static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
117 : : {
118 : 0 : struct dma_buf *dmabuf;
119 : :
120 : 0 : if (!is_dma_buf_file(file))
121 : : return -EINVAL;
122 : :
123 : 0 : dmabuf = file->private_data;
124 : :
125 : : /* check if buffer supports mmap */
126 [ # # ]: 0 : if (!dmabuf->ops->mmap)
127 : : return -EINVAL;
128 : :
129 : : /* check for overflowing the buffer's size */
130 [ # # ]: 0 : if (vma->vm_pgoff + vma_pages(vma) >
131 [ # # ]: 0 : dmabuf->size >> PAGE_SHIFT)
132 : : return -EINVAL;
133 : :
134 : 0 : return dmabuf->ops->mmap(dmabuf, vma);
135 : : }
136 : :
137 : 0 : static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
138 : : {
139 : 0 : struct dma_buf *dmabuf;
140 : 0 : loff_t base;
141 : :
142 : 0 : if (!is_dma_buf_file(file))
143 : : return -EBADF;
144 : :
145 : 0 : dmabuf = file->private_data;
146 : :
147 : : /* only support discovering the end of the buffer,
148 : : but also allow SEEK_SET to maintain the idiomatic
149 : : SEEK_END(0), SEEK_CUR(0) pattern */
150 [ # # ]: 0 : if (whence == SEEK_END)
151 : 0 : base = dmabuf->size;
152 [ # # ]: 0 : else if (whence == SEEK_SET)
153 : : base = 0;
154 : : else
155 : : return -EINVAL;
156 : :
157 [ # # ]: 0 : if (offset != 0)
158 : : return -EINVAL;
159 : :
160 : 0 : return base + offset;
161 : : }
162 : :
163 : : /**
164 : : * DOC: fence polling
165 : : *
166 : : * To support cross-device and cross-driver synchronization of buffer access
167 : : * implicit fences (represented internally in the kernel with &struct fence) can
168 : : * be attached to a &dma_buf. The glue for that and a few related things are
169 : : * provided in the &dma_resv structure.
170 : : *
171 : : * Userspace can query the state of these implicitly tracked fences using poll()
172 : : * and related system calls:
173 : : *
174 : : * - Checking for EPOLLIN, i.e. read access, can be use to query the state of the
175 : : * most recent write or exclusive fence.
176 : : *
177 : : * - Checking for EPOLLOUT, i.e. write access, can be used to query the state of
178 : : * all attached fences, shared and exclusive ones.
179 : : *
180 : : * Note that this only signals the completion of the respective fences, i.e. the
181 : : * DMA transfers are complete. Cache flushing and any other necessary
182 : : * preparations before CPU access can begin still need to happen.
183 : : */
184 : :
185 : 0 : static void dma_buf_poll_cb(struct dma_fence *fence, struct dma_fence_cb *cb)
186 : : {
187 : 0 : struct dma_buf_poll_cb_t *dcb = (struct dma_buf_poll_cb_t *)cb;
188 : 0 : unsigned long flags;
189 : :
190 : 0 : spin_lock_irqsave(&dcb->poll->lock, flags);
191 : 0 : wake_up_locked_poll(dcb->poll, dcb->active);
192 : 0 : dcb->active = 0;
193 : 0 : spin_unlock_irqrestore(&dcb->poll->lock, flags);
194 : 0 : }
195 : :
196 : 0 : static __poll_t dma_buf_poll(struct file *file, poll_table *poll)
197 : : {
198 : 0 : struct dma_buf *dmabuf;
199 : 0 : struct dma_resv *resv;
200 : 0 : struct dma_resv_list *fobj;
201 : 0 : struct dma_fence *fence_excl;
202 : 0 : __poll_t events;
203 : 0 : unsigned shared_count, seq;
204 : :
205 : 0 : dmabuf = file->private_data;
206 [ # # # # ]: 0 : if (!dmabuf || !dmabuf->resv)
207 : : return EPOLLERR;
208 : :
209 : 0 : resv = dmabuf->resv;
210 : :
211 [ # # ]: 0 : poll_wait(file, &dmabuf->poll, poll);
212 : :
213 [ # # ]: 0 : events = poll_requested_events(poll) & (EPOLLIN | EPOLLOUT);
214 [ # # ]: 0 : if (!events)
215 : : return 0;
216 : :
217 : 0 : retry:
218 : 0 : seq = read_seqcount_begin(&resv->seq);
219 : 0 : rcu_read_lock();
220 : :
221 [ # # ]: 0 : fobj = rcu_dereference(resv->fence);
222 [ # # ]: 0 : if (fobj)
223 : 0 : shared_count = fobj->shared_count;
224 : : else
225 : : shared_count = 0;
226 : 0 : fence_excl = rcu_dereference(resv->fence_excl);
227 [ # # ]: 0 : if (read_seqcount_retry(&resv->seq, seq)) {
228 : 0 : rcu_read_unlock();
229 : 0 : goto retry;
230 : : }
231 : :
232 [ # # # # : 0 : if (fence_excl && (!(events & EPOLLOUT) || shared_count == 0)) {
# # ]
233 : 0 : struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_excl;
234 : 0 : __poll_t pevents = EPOLLIN;
235 : :
236 [ # # ]: 0 : if (shared_count == 0)
237 : 0 : pevents |= EPOLLOUT;
238 : :
239 : 0 : spin_lock_irq(&dmabuf->poll.lock);
240 [ # # ]: 0 : if (dcb->active) {
241 : 0 : dcb->active |= pevents;
242 : 0 : events &= ~pevents;
243 : : } else
244 : 0 : dcb->active = pevents;
245 : 0 : spin_unlock_irq(&dmabuf->poll.lock);
246 : :
247 [ # # ]: 0 : if (events & pevents) {
248 : 0 : if (!dma_fence_get_rcu(fence_excl)) {
249 : : /* force a recheck */
250 : 0 : events &= ~pevents;
251 : 0 : dma_buf_poll_cb(NULL, &dcb->cb);
252 [ # # ]: 0 : } else if (!dma_fence_add_callback(fence_excl, &dcb->cb,
253 : : dma_buf_poll_cb)) {
254 : 0 : events &= ~pevents;
255 : 0 : dma_fence_put(fence_excl);
256 : : } else {
257 : : /*
258 : : * No callback queued, wake up any additional
259 : : * waiters.
260 : : */
261 : 0 : dma_fence_put(fence_excl);
262 : 0 : dma_buf_poll_cb(NULL, &dcb->cb);
263 : : }
264 : : }
265 : : }
266 : :
267 [ # # # # ]: 0 : if ((events & EPOLLOUT) && shared_count > 0) {
268 : 0 : struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_shared;
269 : 0 : int i;
270 : :
271 : : /* Only queue a new callback if no event has fired yet */
272 : 0 : spin_lock_irq(&dmabuf->poll.lock);
273 [ # # ]: 0 : if (dcb->active)
274 : 0 : events &= ~EPOLLOUT;
275 : : else
276 : 0 : dcb->active = EPOLLOUT;
277 : 0 : spin_unlock_irq(&dmabuf->poll.lock);
278 : :
279 [ # # ]: 0 : if (!(events & EPOLLOUT))
280 : 0 : goto out;
281 : :
282 [ # # ]: 0 : for (i = 0; i < shared_count; ++i) {
283 : 0 : struct dma_fence *fence = rcu_dereference(fobj->shared[i]);
284 : :
285 [ # # ]: 0 : if (!dma_fence_get_rcu(fence)) {
286 : : /*
287 : : * fence refcount dropped to zero, this means
288 : : * that fobj has been freed
289 : : *
290 : : * call dma_buf_poll_cb and force a recheck!
291 : : */
292 : 0 : events &= ~EPOLLOUT;
293 : 0 : dma_buf_poll_cb(NULL, &dcb->cb);
294 : 0 : break;
295 : : }
296 [ # # ]: 0 : if (!dma_fence_add_callback(fence, &dcb->cb,
297 : : dma_buf_poll_cb)) {
298 : 0 : dma_fence_put(fence);
299 : 0 : events &= ~EPOLLOUT;
300 : 0 : break;
301 : : }
302 : 0 : dma_fence_put(fence);
303 : : }
304 : :
305 : : /* No callback queued, wake up any additional waiters. */
306 [ # # ]: 0 : if (i == shared_count)
307 : 0 : dma_buf_poll_cb(NULL, &dcb->cb);
308 : : }
309 : :
310 : 0 : out:
311 : 0 : rcu_read_unlock();
312 : 0 : return events;
313 : : }
314 : :
315 : : /**
316 : : * dma_buf_set_name - Set a name to a specific dma_buf to track the usage.
317 : : * The name of the dma-buf buffer can only be set when the dma-buf is not
318 : : * attached to any devices. It could theoritically support changing the
319 : : * name of the dma-buf if the same piece of memory is used for multiple
320 : : * purpose between different devices.
321 : : *
322 : : * @dmabuf [in] dmabuf buffer that will be renamed.
323 : : * @buf: [in] A piece of userspace memory that contains the name of
324 : : * the dma-buf.
325 : : *
326 : : * Returns 0 on success. If the dma-buf buffer is already attached to
327 : : * devices, return -EBUSY.
328 : : *
329 : : */
330 : 0 : static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf)
331 : : {
332 : 0 : char *name = strndup_user(buf, DMA_BUF_NAME_LEN);
333 : 0 : long ret = 0;
334 : :
335 [ # # ]: 0 : if (IS_ERR(name))
336 : 0 : return PTR_ERR(name);
337 : :
338 : 0 : dma_resv_lock(dmabuf->resv, NULL);
339 [ # # ]: 0 : if (!list_empty(&dmabuf->attachments)) {
340 : 0 : ret = -EBUSY;
341 : 0 : kfree(name);
342 : 0 : goto out_unlock;
343 : : }
344 : 0 : kfree(dmabuf->name);
345 : 0 : dmabuf->name = name;
346 : :
347 : 0 : out_unlock:
348 : 0 : dma_resv_unlock(dmabuf->resv);
349 : 0 : return ret;
350 : : }
351 : :
352 : 0 : static long dma_buf_ioctl(struct file *file,
353 : : unsigned int cmd, unsigned long arg)
354 : : {
355 : 0 : struct dma_buf *dmabuf;
356 : 0 : struct dma_buf_sync sync;
357 : 0 : enum dma_data_direction direction;
358 : 0 : int ret;
359 : :
360 : 0 : dmabuf = file->private_data;
361 : :
362 [ # # # ]: 0 : switch (cmd) {
363 : 0 : case DMA_BUF_IOCTL_SYNC:
364 [ # # ]: 0 : if (copy_from_user(&sync, (void __user *) arg, sizeof(sync)))
365 : : return -EFAULT;
366 : :
367 [ # # ]: 0 : if (sync.flags & ~DMA_BUF_SYNC_VALID_FLAGS_MASK)
368 : : return -EINVAL;
369 : :
370 [ # # ]: 0 : switch (sync.flags & DMA_BUF_SYNC_RW) {
371 : : case DMA_BUF_SYNC_READ:
372 : : direction = DMA_FROM_DEVICE;
373 : : break;
374 : : case DMA_BUF_SYNC_WRITE:
375 : : direction = DMA_TO_DEVICE;
376 : : break;
377 : : case DMA_BUF_SYNC_RW:
378 : : direction = DMA_BIDIRECTIONAL;
379 : : break;
380 : : default:
381 : : return -EINVAL;
382 : : }
383 : :
384 [ # # ]: 0 : if (sync.flags & DMA_BUF_SYNC_END)
385 : 0 : ret = dma_buf_end_cpu_access(dmabuf, direction);
386 : : else
387 : 0 : ret = dma_buf_begin_cpu_access(dmabuf, direction);
388 : :
389 : 0 : return ret;
390 : :
391 : 0 : case DMA_BUF_SET_NAME:
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 : 0 : dma_resv_lock(dmabuf->resv, NULL);
408 [ # # ]: 0 : if (dmabuf->name)
409 : 0 : seq_printf(m, "name:\t%s\n", dmabuf->name);
410 : 0 : dma_resv_unlock(dmabuf->resv);
411 : 0 : }
412 : :
413 : : static const struct file_operations dma_buf_fops = {
414 : : .release = dma_buf_release,
415 : : .mmap = dma_buf_mmap_internal,
416 : : .llseek = dma_buf_llseek,
417 : : .poll = dma_buf_poll,
418 : : .unlocked_ioctl = dma_buf_ioctl,
419 : : .compat_ioctl = compat_ptr_ioctl,
420 : : .show_fdinfo = dma_buf_show_fdinfo,
421 : : };
422 : :
423 : : /*
424 : : * is_dma_buf_file - Check if struct file* is associated with dma_buf
425 : : */
426 : 0 : static inline int is_dma_buf_file(struct file *file)
427 : : {
428 [ # # # # : 0 : return file->f_op == &dma_buf_fops;
# # ]
429 : : }
430 : :
431 : 0 : static struct file *dma_buf_getfile(struct dma_buf *dmabuf, int flags)
432 : : {
433 : 0 : struct file *file;
434 : 0 : struct inode *inode = alloc_anon_inode(dma_buf_mnt->mnt_sb);
435 : :
436 [ # # ]: 0 : if (IS_ERR(inode))
437 : : return ERR_CAST(inode);
438 : :
439 : 0 : inode->i_size = dmabuf->size;
440 : 0 : inode_set_bytes(inode, dmabuf->size);
441 : :
442 : 0 : file = alloc_file_pseudo(inode, dma_buf_mnt, "dmabuf",
443 : : flags, &dma_buf_fops);
444 [ # # ]: 0 : if (IS_ERR(file))
445 : 0 : goto err_alloc_file;
446 : 0 : file->f_flags = flags & (O_ACCMODE | O_NONBLOCK);
447 : 0 : file->private_data = dmabuf;
448 : 0 : file->f_path.dentry->d_fsdata = dmabuf;
449 : :
450 : 0 : return file;
451 : :
452 : : err_alloc_file:
453 : 0 : iput(inode);
454 : 0 : return file;
455 : : }
456 : :
457 : : /**
458 : : * DOC: dma buf device access
459 : : *
460 : : * For device DMA access to a shared DMA buffer the usual sequence of operations
461 : : * is fairly simple:
462 : : *
463 : : * 1. The exporter defines his exporter instance using
464 : : * DEFINE_DMA_BUF_EXPORT_INFO() and calls dma_buf_export() to wrap a private
465 : : * buffer object into a &dma_buf. It then exports that &dma_buf to userspace
466 : : * as a file descriptor by calling dma_buf_fd().
467 : : *
468 : : * 2. Userspace passes this file-descriptors to all drivers it wants this buffer
469 : : * to share with: First the filedescriptor is converted to a &dma_buf using
470 : : * dma_buf_get(). Then the buffer is attached to the device using
471 : : * dma_buf_attach().
472 : : *
473 : : * Up to this stage the exporter is still free to migrate or reallocate the
474 : : * backing storage.
475 : : *
476 : : * 3. Once the buffer is attached to all devices userspace can initiate DMA
477 : : * access to the shared buffer. In the kernel this is done by calling
478 : : * dma_buf_map_attachment() and dma_buf_unmap_attachment().
479 : : *
480 : : * 4. Once a driver is done with a shared buffer it needs to call
481 : : * dma_buf_detach() (after cleaning up any mappings) and then release the
482 : : * reference acquired with dma_buf_get by calling dma_buf_put().
483 : : *
484 : : * For the detailed semantics exporters are expected to implement see
485 : : * &dma_buf_ops.
486 : : */
487 : :
488 : : /**
489 : : * dma_buf_export - Creates a new dma_buf, and associates an anon file
490 : : * with this buffer, so it can be exported.
491 : : * Also connect the allocator specific data and ops to the buffer.
492 : : * Additionally, provide a name string for exporter; useful in debugging.
493 : : *
494 : : * @exp_info: [in] holds all the export related information provided
495 : : * by the exporter. see &struct dma_buf_export_info
496 : : * for further details.
497 : : *
498 : : * Returns, on success, a newly created dma_buf object, which wraps the
499 : : * supplied private data and operations for dma_buf_ops. On either missing
500 : : * ops, or error in allocating struct dma_buf, will return negative error.
501 : : *
502 : : * For most cases the easiest way to create @exp_info is through the
503 : : * %DEFINE_DMA_BUF_EXPORT_INFO macro.
504 : : */
505 : 0 : struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
506 : : {
507 : 0 : struct dma_buf *dmabuf;
508 : 0 : struct dma_resv *resv = exp_info->resv;
509 : 0 : struct file *file;
510 : 0 : size_t alloc_size = sizeof(struct dma_buf);
511 : 0 : int ret;
512 : :
513 [ # # ]: 0 : if (!exp_info->resv)
514 : : alloc_size += sizeof(struct dma_resv);
515 : : else
516 : : /* prevent &dma_buf[1] == dma_buf->resv */
517 : 0 : alloc_size += 1;
518 : :
519 [ # # # # : 0 : if (WARN_ON(!exp_info->priv
# # # # #
# # # #
# ]
520 : : || !exp_info->ops
521 : : || !exp_info->ops->map_dma_buf
522 : : || !exp_info->ops->unmap_dma_buf
523 : : || !exp_info->ops->release)) {
524 : : return ERR_PTR(-EINVAL);
525 : : }
526 : :
527 [ # # # # : 0 : if (WARN_ON(exp_info->ops->cache_sgt_mapping &&
# # # # ]
528 : : exp_info->ops->dynamic_mapping))
529 : : return ERR_PTR(-EINVAL);
530 : :
531 [ # # ]: 0 : if (!try_module_get(exp_info->owner))
532 : : return ERR_PTR(-ENOENT);
533 : :
534 : 0 : dmabuf = kzalloc(alloc_size, GFP_KERNEL);
535 [ # # ]: 0 : if (!dmabuf) {
536 : 0 : ret = -ENOMEM;
537 : 0 : goto err_module;
538 : : }
539 : :
540 : 0 : dmabuf->priv = exp_info->priv;
541 : 0 : dmabuf->ops = exp_info->ops;
542 : 0 : dmabuf->size = exp_info->size;
543 : 0 : dmabuf->exp_name = exp_info->exp_name;
544 : 0 : dmabuf->owner = exp_info->owner;
545 : 0 : init_waitqueue_head(&dmabuf->poll);
546 : 0 : dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll;
547 : 0 : dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0;
548 : :
549 [ # # ]: 0 : if (!resv) {
550 : 0 : resv = (struct dma_resv *)&dmabuf[1];
551 : 0 : dma_resv_init(resv);
552 : : }
553 : 0 : dmabuf->resv = resv;
554 : :
555 : 0 : file = dma_buf_getfile(dmabuf, exp_info->flags);
556 [ # # ]: 0 : if (IS_ERR(file)) {
557 : 0 : ret = PTR_ERR(file);
558 : 0 : goto err_dmabuf;
559 : : }
560 : :
561 : 0 : file->f_mode |= FMODE_LSEEK;
562 : 0 : dmabuf->file = file;
563 : :
564 : 0 : mutex_init(&dmabuf->lock);
565 : 0 : INIT_LIST_HEAD(&dmabuf->attachments);
566 : :
567 : 0 : mutex_lock(&db_list.lock);
568 : 0 : list_add(&dmabuf->list_node, &db_list.head);
569 : 0 : mutex_unlock(&db_list.lock);
570 : :
571 : 0 : return dmabuf;
572 : :
573 : : err_dmabuf:
574 : 0 : kfree(dmabuf);
575 : 0 : err_module:
576 : 0 : module_put(exp_info->owner);
577 : 0 : return ERR_PTR(ret);
578 : : }
579 : : EXPORT_SYMBOL_GPL(dma_buf_export);
580 : :
581 : : /**
582 : : * dma_buf_fd - returns a file descriptor for the given dma_buf
583 : : * @dmabuf: [in] pointer to dma_buf for which fd is required.
584 : : * @flags: [in] flags to give to fd
585 : : *
586 : : * On success, returns an associated 'fd'. Else, returns error.
587 : : */
588 : 0 : int dma_buf_fd(struct dma_buf *dmabuf, int flags)
589 : : {
590 : 0 : int fd;
591 : :
592 [ # # # # ]: 0 : if (!dmabuf || !dmabuf->file)
593 : : return -EINVAL;
594 : :
595 : 0 : fd = get_unused_fd_flags(flags);
596 [ # # ]: 0 : if (fd < 0)
597 : : return fd;
598 : :
599 : 0 : fd_install(fd, dmabuf->file);
600 : :
601 : 0 : return fd;
602 : : }
603 : : EXPORT_SYMBOL_GPL(dma_buf_fd);
604 : :
605 : : /**
606 : : * dma_buf_get - returns the dma_buf structure related to an fd
607 : : * @fd: [in] fd associated with the dma_buf to be returned
608 : : *
609 : : * On success, returns the dma_buf structure associated with an fd; uses
610 : : * file's refcounting done by fget to increase refcount. returns ERR_PTR
611 : : * otherwise.
612 : : */
613 : 0 : struct dma_buf *dma_buf_get(int fd)
614 : : {
615 : 0 : struct file *file;
616 : :
617 : 0 : file = fget(fd);
618 : :
619 [ # # ]: 0 : if (!file)
620 : : return ERR_PTR(-EBADF);
621 : :
622 [ # # ]: 0 : if (!is_dma_buf_file(file)) {
623 : 0 : fput(file);
624 : 0 : return ERR_PTR(-EINVAL);
625 : : }
626 : :
627 : 0 : return file->private_data;
628 : : }
629 : : EXPORT_SYMBOL_GPL(dma_buf_get);
630 : :
631 : : /**
632 : : * dma_buf_put - decreases refcount of the buffer
633 : : * @dmabuf: [in] buffer to reduce refcount of
634 : : *
635 : : * Uses file's refcounting done implicitly by fput().
636 : : *
637 : : * If, as a result of this call, the refcount becomes 0, the 'release' file
638 : : * operation related to this fd is called. It calls &dma_buf_ops.release vfunc
639 : : * in turn, and frees the memory allocated for dmabuf when exported.
640 : : */
641 : 0 : void dma_buf_put(struct dma_buf *dmabuf)
642 : : {
643 [ # # # # : 0 : if (WARN_ON(!dmabuf || !dmabuf->file))
# # # # ]
644 : : return;
645 : :
646 : 0 : fput(dmabuf->file);
647 : : }
648 : : EXPORT_SYMBOL_GPL(dma_buf_put);
649 : :
650 : : /**
651 : : * dma_buf_dynamic_attach - Add the device to dma_buf's attachments list; optionally,
652 : : * calls attach() of dma_buf_ops to allow device-specific attach functionality
653 : : * @dmabuf: [in] buffer to attach device to.
654 : : * @dev: [in] device to be attached.
655 : : * @dynamic_mapping: [in] calling convention for map/unmap
656 : : *
657 : : * Returns struct dma_buf_attachment pointer for this attachment. Attachments
658 : : * must be cleaned up by calling dma_buf_detach().
659 : : *
660 : : * Returns:
661 : : *
662 : : * A pointer to newly created &dma_buf_attachment on success, or a negative
663 : : * error code wrapped into a pointer on failure.
664 : : *
665 : : * Note that this can fail if the backing storage of @dmabuf is in a place not
666 : : * accessible to @dev, and cannot be moved to a more suitable place. This is
667 : : * indicated with the error code -EBUSY.
668 : : */
669 : : struct dma_buf_attachment *
670 : 0 : dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
671 : : bool dynamic_mapping)
672 : : {
673 : 0 : struct dma_buf_attachment *attach;
674 : 0 : int ret;
675 : :
676 [ # # # # ]: 0 : if (WARN_ON(!dmabuf || !dev))
677 : : return ERR_PTR(-EINVAL);
678 : :
679 : 0 : attach = kzalloc(sizeof(*attach), GFP_KERNEL);
680 [ # # ]: 0 : if (!attach)
681 : : return ERR_PTR(-ENOMEM);
682 : :
683 : 0 : attach->dev = dev;
684 : 0 : attach->dmabuf = dmabuf;
685 : 0 : attach->dynamic_mapping = dynamic_mapping;
686 : :
687 [ # # ]: 0 : if (dmabuf->ops->attach) {
688 : 0 : ret = dmabuf->ops->attach(dmabuf, attach);
689 [ # # ]: 0 : if (ret)
690 : 0 : goto err_attach;
691 : : }
692 : 0 : dma_resv_lock(dmabuf->resv, NULL);
693 : 0 : list_add(&attach->node, &dmabuf->attachments);
694 : 0 : dma_resv_unlock(dmabuf->resv);
695 : :
696 : : /* When either the importer or the exporter can't handle dynamic
697 : : * mappings we cache the mapping here to avoid issues with the
698 : : * reservation object lock.
699 : : */
700 [ # # ]: 0 : if (dma_buf_attachment_is_dynamic(attach) !=
701 [ # # ]: 0 : dma_buf_is_dynamic(dmabuf)) {
702 : 0 : struct sg_table *sgt;
703 : :
704 [ # # ]: 0 : if (dma_buf_is_dynamic(attach->dmabuf))
705 : 0 : dma_resv_lock(attach->dmabuf->resv, NULL);
706 : :
707 : 0 : sgt = dmabuf->ops->map_dma_buf(attach, DMA_BIDIRECTIONAL);
708 [ # # ]: 0 : if (!sgt)
709 : 0 : sgt = ERR_PTR(-ENOMEM);
710 [ # # ]: 0 : if (IS_ERR(sgt)) {
711 [ # # ]: 0 : ret = PTR_ERR(sgt);
712 : 0 : goto err_unlock;
713 : : }
714 [ # # ]: 0 : if (dma_buf_is_dynamic(attach->dmabuf))
715 : 0 : dma_resv_unlock(attach->dmabuf->resv);
716 : 0 : attach->sgt = sgt;
717 : 0 : attach->dir = DMA_BIDIRECTIONAL;
718 : : }
719 : :
720 : : return attach;
721 : :
722 : : err_attach:
723 : 0 : kfree(attach);
724 : 0 : return ERR_PTR(ret);
725 : :
726 : : err_unlock:
727 [ # # ]: 0 : if (dma_buf_is_dynamic(attach->dmabuf))
728 : 0 : dma_resv_unlock(attach->dmabuf->resv);
729 : :
730 : 0 : dma_buf_detach(dmabuf, attach);
731 : 0 : return ERR_PTR(ret);
732 : : }
733 : : EXPORT_SYMBOL_GPL(dma_buf_dynamic_attach);
734 : :
735 : : /**
736 : : * dma_buf_attach - Wrapper for dma_buf_dynamic_attach
737 : : * @dmabuf: [in] buffer to attach device to.
738 : : * @dev: [in] device to be attached.
739 : : *
740 : : * Wrapper to call dma_buf_dynamic_attach() for drivers which still use a static
741 : : * mapping.
742 : : */
743 : 0 : struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
744 : : struct device *dev)
745 : : {
746 : 0 : return dma_buf_dynamic_attach(dmabuf, dev, false);
747 : : }
748 : : EXPORT_SYMBOL_GPL(dma_buf_attach);
749 : :
750 : : /**
751 : : * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
752 : : * optionally calls detach() of dma_buf_ops for device-specific detach
753 : : * @dmabuf: [in] buffer to detach from.
754 : : * @attach: [in] attachment to be detached; is free'd after this call.
755 : : *
756 : : * Clean up a device attachment obtained by calling dma_buf_attach().
757 : : */
758 : 0 : void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
759 : : {
760 [ # # # # ]: 0 : if (WARN_ON(!dmabuf || !attach))
761 : : return;
762 : :
763 [ # # ]: 0 : if (attach->sgt) {
764 [ # # ]: 0 : if (dma_buf_is_dynamic(attach->dmabuf))
765 : 0 : dma_resv_lock(attach->dmabuf->resv, NULL);
766 : :
767 : 0 : dmabuf->ops->unmap_dma_buf(attach, attach->sgt, attach->dir);
768 : :
769 [ # # ]: 0 : if (dma_buf_is_dynamic(attach->dmabuf))
770 : 0 : dma_resv_unlock(attach->dmabuf->resv);
771 : : }
772 : :
773 : 0 : dma_resv_lock(dmabuf->resv, NULL);
774 : 0 : list_del(&attach->node);
775 : 0 : dma_resv_unlock(dmabuf->resv);
776 [ # # ]: 0 : if (dmabuf->ops->detach)
777 : 0 : dmabuf->ops->detach(dmabuf, attach);
778 : :
779 : 0 : kfree(attach);
780 : : }
781 : : EXPORT_SYMBOL_GPL(dma_buf_detach);
782 : :
783 : : /**
784 : : * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
785 : : * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
786 : : * dma_buf_ops.
787 : : * @attach: [in] attachment whose scatterlist is to be returned
788 : : * @direction: [in] direction of DMA transfer
789 : : *
790 : : * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR
791 : : * on error. May return -EINTR if it is interrupted by a signal.
792 : : *
793 : : * A mapping must be unmapped by using dma_buf_unmap_attachment(). Note that
794 : : * the underlying backing storage is pinned for as long as a mapping exists,
795 : : * therefore users/importers should not hold onto a mapping for undue amounts of
796 : : * time.
797 : : */
798 : 0 : struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
799 : : enum dma_data_direction direction)
800 : : {
801 : 0 : struct sg_table *sg_table;
802 : :
803 : 0 : might_sleep();
804 : :
805 [ # # # # : 0 : if (WARN_ON(!attach || !attach->dmabuf))
# # # # ]
806 : : return ERR_PTR(-EINVAL);
807 : :
808 [ # # ]: 0 : if (dma_buf_attachment_is_dynamic(attach))
809 : 0 : dma_resv_assert_held(attach->dmabuf->resv);
810 : :
811 [ # # ]: 0 : if (attach->sgt) {
812 : : /*
813 : : * Two mappings with different directions for the same
814 : : * attachment are not allowed.
815 : : */
816 [ # # # # ]: 0 : if (attach->dir != direction &&
817 : : attach->dir != DMA_BIDIRECTIONAL)
818 : : return ERR_PTR(-EBUSY);
819 : :
820 : 0 : return attach->sgt;
821 : : }
822 : :
823 : 0 : if (dma_buf_is_dynamic(attach->dmabuf))
824 : 0 : dma_resv_assert_held(attach->dmabuf->resv);
825 : :
826 : 0 : sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
827 [ # # ]: 0 : if (!sg_table)
828 : 0 : sg_table = ERR_PTR(-ENOMEM);
829 : :
830 [ # # # # ]: 0 : if (!IS_ERR(sg_table) && attach->dmabuf->ops->cache_sgt_mapping) {
831 : 0 : attach->sgt = sg_table;
832 : 0 : attach->dir = direction;
833 : : }
834 : :
835 : : return sg_table;
836 : : }
837 : : EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
838 : :
839 : : /**
840 : : * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
841 : : * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
842 : : * dma_buf_ops.
843 : : * @attach: [in] attachment to unmap buffer from
844 : : * @sg_table: [in] scatterlist info of the buffer to unmap
845 : : * @direction: [in] direction of DMA transfer
846 : : *
847 : : * This unmaps a DMA mapping for @attached obtained by dma_buf_map_attachment().
848 : : */
849 : 0 : void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
850 : : struct sg_table *sg_table,
851 : : enum dma_data_direction direction)
852 : : {
853 : 0 : might_sleep();
854 : :
855 [ # # # # : 0 : if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
# # # # #
# ]
856 : : return;
857 : :
858 [ # # ]: 0 : if (dma_buf_attachment_is_dynamic(attach))
859 : 0 : dma_resv_assert_held(attach->dmabuf->resv);
860 : :
861 [ # # ]: 0 : if (attach->sgt == sg_table)
862 : : return;
863 : :
864 : 0 : if (dma_buf_is_dynamic(attach->dmabuf))
865 : 0 : dma_resv_assert_held(attach->dmabuf->resv);
866 : :
867 : 0 : attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction);
868 : : }
869 : : EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
870 : :
871 : : /**
872 : : * DOC: cpu access
873 : : *
874 : : * There are mutliple reasons for supporting CPU access to a dma buffer object:
875 : : *
876 : : * - Fallback operations in the kernel, for example when a device is connected
877 : : * over USB and the kernel needs to shuffle the data around first before
878 : : * sending it away. Cache coherency is handled by braketing any transactions
879 : : * with calls to dma_buf_begin_cpu_access() and dma_buf_end_cpu_access()
880 : : * access.
881 : : *
882 : : * Since for most kernel internal dma-buf accesses need the entire buffer, a
883 : : * vmap interface is introduced. Note that on very old 32-bit architectures
884 : : * vmalloc space might be limited and result in vmap calls failing.
885 : : *
886 : : * Interfaces::
887 : : * void \*dma_buf_vmap(struct dma_buf \*dmabuf)
888 : : * void dma_buf_vunmap(struct dma_buf \*dmabuf, void \*vaddr)
889 : : *
890 : : * The vmap call can fail if there is no vmap support in the exporter, or if
891 : : * it runs out of vmalloc space. Fallback to kmap should be implemented. Note
892 : : * that the dma-buf layer keeps a reference count for all vmap access and
893 : : * calls down into the exporter's vmap function only when no vmapping exists,
894 : : * and only unmaps it once. Protection against concurrent vmap/vunmap calls is
895 : : * provided by taking the dma_buf->lock mutex.
896 : : *
897 : : * - For full compatibility on the importer side with existing userspace
898 : : * interfaces, which might already support mmap'ing buffers. This is needed in
899 : : * many processing pipelines (e.g. feeding a software rendered image into a
900 : : * hardware pipeline, thumbnail creation, snapshots, ...). Also, Android's ION
901 : : * framework already supported this and for DMA buffer file descriptors to
902 : : * replace ION buffers mmap support was needed.
903 : : *
904 : : * There is no special interfaces, userspace simply calls mmap on the dma-buf
905 : : * fd. But like for CPU access there's a need to braket the actual access,
906 : : * which is handled by the ioctl (DMA_BUF_IOCTL_SYNC). Note that
907 : : * DMA_BUF_IOCTL_SYNC can fail with -EAGAIN or -EINTR, in which case it must
908 : : * be restarted.
909 : : *
910 : : * Some systems might need some sort of cache coherency management e.g. when
911 : : * CPU and GPU domains are being accessed through dma-buf at the same time.
912 : : * To circumvent this problem there are begin/end coherency markers, that
913 : : * forward directly to existing dma-buf device drivers vfunc hooks. Userspace
914 : : * can make use of those markers through the DMA_BUF_IOCTL_SYNC ioctl. The
915 : : * sequence would be used like following:
916 : : *
917 : : * - mmap dma-buf fd
918 : : * - for each drawing/upload cycle in CPU 1. SYNC_START ioctl, 2. read/write
919 : : * to mmap area 3. SYNC_END ioctl. This can be repeated as often as you
920 : : * want (with the new data being consumed by say the GPU or the scanout
921 : : * device)
922 : : * - munmap once you don't need the buffer any more
923 : : *
924 : : * For correctness and optimal performance, it is always required to use
925 : : * SYNC_START and SYNC_END before and after, respectively, when accessing the
926 : : * mapped address. Userspace cannot rely on coherent access, even when there
927 : : * are systems where it just works without calling these ioctls.
928 : : *
929 : : * - And as a CPU fallback in userspace processing pipelines.
930 : : *
931 : : * Similar to the motivation for kernel cpu access it is again important that
932 : : * the userspace code of a given importing subsystem can use the same
933 : : * interfaces with a imported dma-buf buffer object as with a native buffer
934 : : * object. This is especially important for drm where the userspace part of
935 : : * contemporary OpenGL, X, and other drivers is huge, and reworking them to
936 : : * use a different way to mmap a buffer rather invasive.
937 : : *
938 : : * The assumption in the current dma-buf interfaces is that redirecting the
939 : : * initial mmap is all that's needed. A survey of some of the existing
940 : : * subsystems shows that no driver seems to do any nefarious thing like
941 : : * syncing up with outstanding asynchronous processing on the device or
942 : : * allocating special resources at fault time. So hopefully this is good
943 : : * enough, since adding interfaces to intercept pagefaults and allow pte
944 : : * shootdowns would increase the complexity quite a bit.
945 : : *
946 : : * Interface::
947 : : * int dma_buf_mmap(struct dma_buf \*, struct vm_area_struct \*,
948 : : * unsigned long);
949 : : *
950 : : * If the importing subsystem simply provides a special-purpose mmap call to
951 : : * set up a mapping in userspace, calling do_mmap with dma_buf->file will
952 : : * equally achieve that for a dma-buf object.
953 : : */
954 : :
955 : 0 : static int __dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
956 : : enum dma_data_direction direction)
957 : : {
958 : 0 : bool write = (direction == DMA_BIDIRECTIONAL ||
959 : : direction == DMA_TO_DEVICE);
960 : 0 : struct dma_resv *resv = dmabuf->resv;
961 : 0 : long ret;
962 : :
963 : : /* Wait on any implicit rendering fences */
964 : 0 : ret = dma_resv_wait_timeout_rcu(resv, write, true,
965 : : MAX_SCHEDULE_TIMEOUT);
966 : 0 : if (ret < 0)
967 : : return ret;
968 : :
969 : : return 0;
970 : : }
971 : :
972 : : /**
973 : : * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
974 : : * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
975 : : * preparations. Coherency is only guaranteed in the specified range for the
976 : : * specified access direction.
977 : : * @dmabuf: [in] buffer to prepare cpu access for.
978 : : * @direction: [in] length of range for cpu access.
979 : : *
980 : : * After the cpu access is complete the caller should call
981 : : * dma_buf_end_cpu_access(). Only when cpu access is braketed by both calls is
982 : : * it guaranteed to be coherent with other DMA access.
983 : : *
984 : : * Can return negative error values, returns 0 on success.
985 : : */
986 : 0 : int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
987 : : enum dma_data_direction direction)
988 : : {
989 : 0 : int ret = 0;
990 : :
991 [ # # # # ]: 0 : if (WARN_ON(!dmabuf))
992 : : return -EINVAL;
993 : :
994 [ # # ]: 0 : if (dmabuf->ops->begin_cpu_access)
995 : 0 : ret = dmabuf->ops->begin_cpu_access(dmabuf, direction);
996 : :
997 : : /* Ensure that all fences are waited upon - but we first allow
998 : : * the native handler the chance to do so more efficiently if it
999 : : * chooses. A double invocation here will be reasonably cheap no-op.
1000 : : */
1001 [ # # ]: 0 : if (ret == 0)
1002 : 0 : ret = __dma_buf_begin_cpu_access(dmabuf, direction);
1003 : :
1004 : : return ret;
1005 : : }
1006 : : EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access);
1007 : :
1008 : : /**
1009 : : * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
1010 : : * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
1011 : : * actions. Coherency is only guaranteed in the specified range for the
1012 : : * specified access direction.
1013 : : * @dmabuf: [in] buffer to complete cpu access for.
1014 : : * @direction: [in] length of range for cpu access.
1015 : : *
1016 : : * This terminates CPU access started with dma_buf_begin_cpu_access().
1017 : : *
1018 : : * Can return negative error values, returns 0 on success.
1019 : : */
1020 : 0 : int dma_buf_end_cpu_access(struct dma_buf *dmabuf,
1021 : : enum dma_data_direction direction)
1022 : : {
1023 : 0 : int ret = 0;
1024 : :
1025 [ # # # # ]: 0 : WARN_ON(!dmabuf);
1026 : :
1027 [ # # # # ]: 0 : if (dmabuf->ops->end_cpu_access)
1028 : 0 : ret = dmabuf->ops->end_cpu_access(dmabuf, direction);
1029 : :
1030 : 0 : return ret;
1031 : : }
1032 : : EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
1033 : :
1034 : :
1035 : : /**
1036 : : * dma_buf_mmap - Setup up a userspace mmap with the given vma
1037 : : * @dmabuf: [in] buffer that should back the vma
1038 : : * @vma: [in] vma for the mmap
1039 : : * @pgoff: [in] offset in pages where this mmap should start within the
1040 : : * dma-buf buffer.
1041 : : *
1042 : : * This function adjusts the passed in vma so that it points at the file of the
1043 : : * dma_buf operation. It also adjusts the starting pgoff and does bounds
1044 : : * checking on the size of the vma. Then it calls the exporters mmap function to
1045 : : * set up the mapping.
1046 : : *
1047 : : * Can return negative error values, returns 0 on success.
1048 : : */
1049 : 0 : int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
1050 : : unsigned long pgoff)
1051 : : {
1052 : 0 : struct file *oldfile;
1053 : 0 : int ret;
1054 : :
1055 [ # # # # ]: 0 : if (WARN_ON(!dmabuf || !vma))
1056 : : return -EINVAL;
1057 : :
1058 : : /* check if buffer supports mmap */
1059 [ # # ]: 0 : if (!dmabuf->ops->mmap)
1060 : : return -EINVAL;
1061 : :
1062 : : /* check for offset overflow */
1063 [ # # ]: 0 : if (pgoff + vma_pages(vma) < pgoff)
1064 : : return -EOVERFLOW;
1065 : :
1066 : : /* check for overflowing the buffer's size */
1067 [ # # ]: 0 : if (pgoff + vma_pages(vma) >
1068 [ # # ]: 0 : dmabuf->size >> PAGE_SHIFT)
1069 : : return -EINVAL;
1070 : :
1071 : : /* readjust the vma */
1072 : 0 : get_file(dmabuf->file);
1073 : 0 : oldfile = vma->vm_file;
1074 : 0 : vma->vm_file = dmabuf->file;
1075 : 0 : vma->vm_pgoff = pgoff;
1076 : :
1077 : 0 : ret = dmabuf->ops->mmap(dmabuf, vma);
1078 [ # # ]: 0 : if (ret) {
1079 : : /* restore old parameters on failure */
1080 : 0 : vma->vm_file = oldfile;
1081 : 0 : fput(dmabuf->file);
1082 : : } else {
1083 [ # # ]: 0 : if (oldfile)
1084 : 0 : fput(oldfile);
1085 : : }
1086 : : return ret;
1087 : :
1088 : : }
1089 : : EXPORT_SYMBOL_GPL(dma_buf_mmap);
1090 : :
1091 : : /**
1092 : : * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
1093 : : * address space. Same restrictions as for vmap and friends apply.
1094 : : * @dmabuf: [in] buffer to vmap
1095 : : *
1096 : : * This call may fail due to lack of virtual mapping address space.
1097 : : * These calls are optional in drivers. The intended use for them
1098 : : * is for mapping objects linear in kernel space for high use objects.
1099 : : * Please attempt to use kmap/kunmap before thinking about these interfaces.
1100 : : *
1101 : : * Returns NULL on error.
1102 : : */
1103 : 0 : void *dma_buf_vmap(struct dma_buf *dmabuf)
1104 : : {
1105 : 0 : void *ptr;
1106 : :
1107 [ # # # # ]: 0 : if (WARN_ON(!dmabuf))
1108 : : return NULL;
1109 : :
1110 [ # # ]: 0 : if (!dmabuf->ops->vmap)
1111 : : return NULL;
1112 : :
1113 : 0 : mutex_lock(&dmabuf->lock);
1114 [ # # ]: 0 : if (dmabuf->vmapping_counter) {
1115 : 0 : dmabuf->vmapping_counter++;
1116 [ # # ]: 0 : BUG_ON(!dmabuf->vmap_ptr);
1117 : 0 : ptr = dmabuf->vmap_ptr;
1118 : 0 : goto out_unlock;
1119 : : }
1120 : :
1121 [ # # ]: 0 : BUG_ON(dmabuf->vmap_ptr);
1122 : :
1123 : 0 : ptr = dmabuf->ops->vmap(dmabuf);
1124 [ # # # # ]: 0 : if (WARN_ON_ONCE(IS_ERR(ptr)))
1125 : : ptr = NULL;
1126 [ # # ]: 0 : if (!ptr)
1127 : 0 : goto out_unlock;
1128 : :
1129 : 0 : dmabuf->vmap_ptr = ptr;
1130 : 0 : dmabuf->vmapping_counter = 1;
1131 : :
1132 : 0 : out_unlock:
1133 : 0 : mutex_unlock(&dmabuf->lock);
1134 : 0 : return ptr;
1135 : : }
1136 : : EXPORT_SYMBOL_GPL(dma_buf_vmap);
1137 : :
1138 : : /**
1139 : : * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
1140 : : * @dmabuf: [in] buffer to vunmap
1141 : : * @vaddr: [in] vmap to vunmap
1142 : : */
1143 : 0 : void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
1144 : : {
1145 [ # # # # ]: 0 : if (WARN_ON(!dmabuf))
1146 : : return;
1147 : :
1148 [ # # ]: 0 : BUG_ON(!dmabuf->vmap_ptr);
1149 [ # # ]: 0 : BUG_ON(dmabuf->vmapping_counter == 0);
1150 [ # # ]: 0 : BUG_ON(dmabuf->vmap_ptr != vaddr);
1151 : :
1152 : 0 : mutex_lock(&dmabuf->lock);
1153 [ # # ]: 0 : if (--dmabuf->vmapping_counter == 0) {
1154 [ # # ]: 0 : if (dmabuf->ops->vunmap)
1155 : 0 : dmabuf->ops->vunmap(dmabuf, vaddr);
1156 : 0 : dmabuf->vmap_ptr = NULL;
1157 : : }
1158 : 0 : mutex_unlock(&dmabuf->lock);
1159 : : }
1160 : : EXPORT_SYMBOL_GPL(dma_buf_vunmap);
1161 : :
1162 : : #ifdef CONFIG_DEBUG_FS
1163 : 0 : static int dma_buf_debug_show(struct seq_file *s, void *unused)
1164 : : {
1165 : 0 : int ret;
1166 : 0 : struct dma_buf *buf_obj;
1167 : 0 : struct dma_buf_attachment *attach_obj;
1168 : 0 : struct dma_resv *robj;
1169 : 0 : struct dma_resv_list *fobj;
1170 : 0 : struct dma_fence *fence;
1171 : 0 : unsigned seq;
1172 : 0 : int count = 0, attach_count, shared_count, i;
1173 : 0 : size_t size = 0;
1174 : :
1175 : 0 : ret = mutex_lock_interruptible(&db_list.lock);
1176 : :
1177 [ # # ]: 0 : if (ret)
1178 : : return ret;
1179 : :
1180 : 0 : seq_puts(s, "\nDma-buf Objects:\n");
1181 : 0 : seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\t%-8s\n",
1182 : : "size", "flags", "mode", "count", "ino");
1183 : :
1184 [ # # ]: 0 : list_for_each_entry(buf_obj, &db_list.head, list_node) {
1185 : :
1186 : 0 : ret = dma_resv_lock_interruptible(buf_obj->resv, NULL);
1187 [ # # ]: 0 : if (ret)
1188 : 0 : goto error_unlock;
1189 : :
1190 : 0 : seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\n",
1191 : : buf_obj->size,
1192 : 0 : buf_obj->file->f_flags, buf_obj->file->f_mode,
1193 : 0 : file_count(buf_obj->file),
1194 : : buf_obj->exp_name,
1195 : 0 : file_inode(buf_obj->file)->i_ino,
1196 [ # # ]: 0 : buf_obj->name ?: "");
1197 : :
1198 : 0 : robj = buf_obj->resv;
1199 : 0 : while (true) {
1200 : 0 : seq = read_seqcount_begin(&robj->seq);
1201 : 0 : rcu_read_lock();
1202 [ # # ]: 0 : fobj = rcu_dereference(robj->fence);
1203 [ # # ]: 0 : shared_count = fobj ? fobj->shared_count : 0;
1204 : 0 : fence = rcu_dereference(robj->fence_excl);
1205 [ # # ]: 0 : if (!read_seqcount_retry(&robj->seq, seq))
1206 : : break;
1207 : 0 : rcu_read_unlock();
1208 : : }
1209 : :
1210 [ # # ]: 0 : if (fence)
1211 [ # # ]: 0 : seq_printf(s, "\tExclusive fence: %s %s %ssignalled\n",
1212 : 0 : fence->ops->get_driver_name(fence),
1213 : 0 : fence->ops->get_timeline_name(fence),
1214 : 0 : dma_fence_is_signaled(fence) ? "" : "un");
1215 [ # # ]: 0 : for (i = 0; i < shared_count; i++) {
1216 : 0 : fence = rcu_dereference(fobj->shared[i]);
1217 [ # # ]: 0 : if (!dma_fence_get_rcu(fence))
1218 : 0 : continue;
1219 [ # # ]: 0 : seq_printf(s, "\tShared fence: %s %s %ssignalled\n",
1220 : 0 : fence->ops->get_driver_name(fence),
1221 : 0 : fence->ops->get_timeline_name(fence),
1222 : 0 : dma_fence_is_signaled(fence) ? "" : "un");
1223 : 0 : dma_fence_put(fence);
1224 : : }
1225 : 0 : rcu_read_unlock();
1226 : :
1227 : 0 : seq_puts(s, "\tAttached Devices:\n");
1228 : 0 : attach_count = 0;
1229 : :
1230 [ # # ]: 0 : list_for_each_entry(attach_obj, &buf_obj->attachments, node) {
1231 [ # # ]: 0 : seq_printf(s, "\t%s\n", dev_name(attach_obj->dev));
1232 : 0 : attach_count++;
1233 : : }
1234 : 0 : dma_resv_unlock(buf_obj->resv);
1235 : :
1236 : 0 : seq_printf(s, "Total %d devices attached\n\n",
1237 : : attach_count);
1238 : :
1239 : 0 : count++;
1240 : 0 : size += buf_obj->size;
1241 : : }
1242 : :
1243 : 0 : seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size);
1244 : :
1245 : 0 : mutex_unlock(&db_list.lock);
1246 : 0 : return 0;
1247 : :
1248 : : error_unlock:
1249 : 0 : mutex_unlock(&db_list.lock);
1250 : 0 : return ret;
1251 : : }
1252 : :
1253 : 0 : DEFINE_SHOW_ATTRIBUTE(dma_buf_debug);
1254 : :
1255 : : static struct dentry *dma_buf_debugfs_dir;
1256 : :
1257 : 28 : static int dma_buf_init_debugfs(void)
1258 : : {
1259 : 28 : struct dentry *d;
1260 : 28 : int err = 0;
1261 : :
1262 : 28 : d = debugfs_create_dir("dma_buf", NULL);
1263 [ - + ]: 28 : if (IS_ERR(d))
1264 : 0 : return PTR_ERR(d);
1265 : :
1266 : 28 : dma_buf_debugfs_dir = d;
1267 : :
1268 : 28 : d = debugfs_create_file("bufinfo", S_IRUGO, dma_buf_debugfs_dir,
1269 : : NULL, &dma_buf_debug_fops);
1270 [ - + ]: 28 : if (IS_ERR(d)) {
1271 : 0 : pr_debug("dma_buf: debugfs: failed to create node bufinfo\n");
1272 : 0 : debugfs_remove_recursive(dma_buf_debugfs_dir);
1273 : 0 : dma_buf_debugfs_dir = NULL;
1274 : 0 : err = PTR_ERR(d);
1275 : : }
1276 : :
1277 : : return err;
1278 : : }
1279 : :
1280 : 0 : static void dma_buf_uninit_debugfs(void)
1281 : : {
1282 : 0 : debugfs_remove_recursive(dma_buf_debugfs_dir);
1283 : : }
1284 : : #else
1285 : : static inline int dma_buf_init_debugfs(void)
1286 : : {
1287 : : return 0;
1288 : : }
1289 : : static inline void dma_buf_uninit_debugfs(void)
1290 : : {
1291 : : }
1292 : : #endif
1293 : :
1294 : 28 : static int __init dma_buf_init(void)
1295 : : {
1296 : 28 : dma_buf_mnt = kern_mount(&dma_buf_fs_type);
1297 [ - + ]: 28 : if (IS_ERR(dma_buf_mnt))
1298 : 0 : return PTR_ERR(dma_buf_mnt);
1299 : :
1300 : 28 : mutex_init(&db_list.lock);
1301 : 28 : INIT_LIST_HEAD(&db_list.head);
1302 : 28 : dma_buf_init_debugfs();
1303 : 28 : return 0;
1304 : : }
1305 : : subsys_initcall(dma_buf_init);
1306 : :
1307 : 0 : static void __exit dma_buf_deinit(void)
1308 : : {
1309 : 0 : dma_buf_uninit_debugfs();
1310 : 0 : kern_unmount(dma_buf_mnt);
1311 : 0 : }
1312 : : __exitcall(dma_buf_deinit);
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