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caab277b | 1 | // SPDX-License-Identifier: GPL-2.0-only |
d15bd7ee SS |
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. | |
d15bd7ee SS |
12 | */ |
13 | ||
14 | #include <linux/fs.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/dma-buf.h> | |
f54d1867 | 17 | #include <linux/dma-fence.h> |
d15bd7ee SS |
18 | #include <linux/anon_inodes.h> |
19 | #include <linux/export.h> | |
b89e3563 | 20 | #include <linux/debugfs.h> |
9abdffe2 | 21 | #include <linux/module.h> |
b89e3563 | 22 | #include <linux/seq_file.h> |
9b495a58 | 23 | #include <linux/poll.h> |
52791eee | 24 | #include <linux/dma-resv.h> |
b02da6f8 | 25 | #include <linux/mm.h> |
ed63bb1d | 26 | #include <linux/mount.h> |
933a90bf | 27 | #include <linux/pseudo_fs.h> |
d15bd7ee | 28 | |
c11e391d | 29 | #include <uapi/linux/dma-buf.h> |
ed63bb1d | 30 | #include <uapi/linux/magic.h> |
c11e391d | 31 | |
d15bd7ee SS |
32 | static inline int is_dma_buf_file(struct file *); |
33 | ||
b89e3563 SS |
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 | ||
bb2bb903 GH |
41 | 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 | dmabuf = dentry->d_fsdata; | |
15fd552d | 48 | dma_resv_lock(dmabuf->resv, NULL); |
bb2bb903 GH |
49 | if (dmabuf->name) |
50 | ret = strlcpy(name, dmabuf->name, DMA_BUF_NAME_LEN); | |
15fd552d | 51 | dma_resv_unlock(dmabuf->resv); |
bb2bb903 GH |
52 | |
53 | return dynamic_dname(dentry, buffer, buflen, "/%s:%s", | |
54 | dentry->d_name.name, ret > 0 ? name : ""); | |
55 | } | |
56 | ||
ed63bb1d | 57 | static const struct dentry_operations dma_buf_dentry_ops = { |
bb2bb903 | 58 | .d_dname = dmabuffs_dname, |
ed63bb1d GH |
59 | }; |
60 | ||
61 | static struct vfsmount *dma_buf_mnt; | |
62 | ||
933a90bf | 63 | static int dma_buf_fs_init_context(struct fs_context *fc) |
ed63bb1d | 64 | { |
933a90bf LT |
65 | struct pseudo_fs_context *ctx; |
66 | ||
67 | ctx = init_pseudo(fc, DMA_BUF_MAGIC); | |
68 | if (!ctx) | |
69 | return -ENOMEM; | |
70 | ctx->dops = &dma_buf_dentry_ops; | |
71 | return 0; | |
ed63bb1d GH |
72 | } |
73 | ||
74 | static struct file_system_type dma_buf_fs_type = { | |
75 | .name = "dmabuf", | |
933a90bf | 76 | .init_fs_context = dma_buf_fs_init_context, |
ed63bb1d GH |
77 | .kill_sb = kill_anon_super, |
78 | }; | |
79 | ||
d15bd7ee SS |
80 | static int dma_buf_release(struct inode *inode, struct file *file) |
81 | { | |
82 | struct dma_buf *dmabuf; | |
83 | ||
84 | if (!is_dma_buf_file(file)) | |
85 | return -EINVAL; | |
86 | ||
87 | dmabuf = file->private_data; | |
88 | ||
f00b4dad DV |
89 | BUG_ON(dmabuf->vmapping_counter); |
90 | ||
9b495a58 ML |
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 | BUG_ON(dmabuf->cb_shared.active || dmabuf->cb_excl.active); | |
100 | ||
d15bd7ee | 101 | dmabuf->ops->release(dmabuf); |
b89e3563 SS |
102 | |
103 | mutex_lock(&db_list.lock); | |
104 | list_del(&dmabuf->list_node); | |
105 | mutex_unlock(&db_list.lock); | |
106 | ||
52791eee CK |
107 | if (dmabuf->resv == (struct dma_resv *)&dmabuf[1]) |
108 | dma_resv_fini(dmabuf->resv); | |
3aac4502 | 109 | |
9abdffe2 | 110 | module_put(dmabuf->owner); |
d1f37226 | 111 | kfree(dmabuf->name); |
d15bd7ee SS |
112 | kfree(dmabuf); |
113 | return 0; | |
114 | } | |
115 | ||
4c78513e DV |
116 | static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) |
117 | { | |
118 | struct dma_buf *dmabuf; | |
119 | ||
120 | if (!is_dma_buf_file(file)) | |
121 | return -EINVAL; | |
122 | ||
123 | dmabuf = file->private_data; | |
124 | ||
e3a9d6c5 AD |
125 | /* check if buffer supports mmap */ |
126 | if (!dmabuf->ops->mmap) | |
127 | return -EINVAL; | |
128 | ||
4c78513e | 129 | /* check for overflowing the buffer's size */ |
b02da6f8 | 130 | if (vma->vm_pgoff + vma_pages(vma) > |
4c78513e DV |
131 | dmabuf->size >> PAGE_SHIFT) |
132 | return -EINVAL; | |
133 | ||
134 | return dmabuf->ops->mmap(dmabuf, vma); | |
135 | } | |
136 | ||
19e8697b CJHR |
137 | static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence) |
138 | { | |
139 | struct dma_buf *dmabuf; | |
140 | loff_t base; | |
141 | ||
142 | if (!is_dma_buf_file(file)) | |
143 | return -EBADF; | |
144 | ||
145 | 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 | if (whence == SEEK_END) | |
151 | base = dmabuf->size; | |
152 | else if (whence == SEEK_SET) | |
153 | base = 0; | |
154 | else | |
155 | return -EINVAL; | |
156 | ||
157 | if (offset != 0) | |
158 | return -EINVAL; | |
159 | ||
160 | return base + offset; | |
161 | } | |
162 | ||
e7e21c72 DV |
163 | /** |
164 | * DOC: fence polling | |
165 | * | |
166 | * To support cross-device and cross-driver synchronization of buffer access | |
f641d3b5 | 167 | * implicit fences (represented internally in the kernel with &struct fence) can |
e7e21c72 | 168 | * be attached to a &dma_buf. The glue for that and a few related things are |
52791eee | 169 | * provided in the &dma_resv structure. |
e7e21c72 DV |
170 | * |
171 | * Userspace can query the state of these implicitly tracked fences using poll() | |
172 | * and related system calls: | |
173 | * | |
a9a08845 | 174 | * - Checking for EPOLLIN, i.e. read access, can be use to query the state of the |
e7e21c72 DV |
175 | * most recent write or exclusive fence. |
176 | * | |
a9a08845 | 177 | * - Checking for EPOLLOUT, i.e. write access, can be used to query the state of |
e7e21c72 DV |
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 | ||
f54d1867 | 185 | static void dma_buf_poll_cb(struct dma_fence *fence, struct dma_fence_cb *cb) |
9b495a58 ML |
186 | { |
187 | struct dma_buf_poll_cb_t *dcb = (struct dma_buf_poll_cb_t *)cb; | |
188 | unsigned long flags; | |
189 | ||
190 | spin_lock_irqsave(&dcb->poll->lock, flags); | |
191 | wake_up_locked_poll(dcb->poll, dcb->active); | |
192 | dcb->active = 0; | |
193 | spin_unlock_irqrestore(&dcb->poll->lock, flags); | |
194 | } | |
195 | ||
afc9a42b | 196 | static __poll_t dma_buf_poll(struct file *file, poll_table *poll) |
9b495a58 ML |
197 | { |
198 | struct dma_buf *dmabuf; | |
52791eee CK |
199 | struct dma_resv *resv; |
200 | struct dma_resv_list *fobj; | |
f54d1867 | 201 | struct dma_fence *fence_excl; |
01699437 | 202 | __poll_t events; |
b016cd6e | 203 | unsigned shared_count, seq; |
9b495a58 ML |
204 | |
205 | dmabuf = file->private_data; | |
206 | if (!dmabuf || !dmabuf->resv) | |
a9a08845 | 207 | return EPOLLERR; |
9b495a58 ML |
208 | |
209 | resv = dmabuf->resv; | |
210 | ||
211 | poll_wait(file, &dmabuf->poll, poll); | |
212 | ||
a9a08845 | 213 | events = poll_requested_events(poll) & (EPOLLIN | EPOLLOUT); |
9b495a58 ML |
214 | if (!events) |
215 | return 0; | |
216 | ||
b016cd6e CW |
217 | retry: |
218 | seq = read_seqcount_begin(&resv->seq); | |
3c3b177a | 219 | rcu_read_lock(); |
b016cd6e CW |
220 | |
221 | fobj = rcu_dereference(resv->fence); | |
222 | if (fobj) | |
223 | shared_count = fobj->shared_count; | |
224 | else | |
225 | shared_count = 0; | |
226 | fence_excl = rcu_dereference(resv->fence_excl); | |
227 | if (read_seqcount_retry(&resv->seq, seq)) { | |
228 | rcu_read_unlock(); | |
229 | goto retry; | |
230 | } | |
231 | ||
a9a08845 | 232 | if (fence_excl && (!(events & EPOLLOUT) || shared_count == 0)) { |
9b495a58 | 233 | struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_excl; |
a9a08845 | 234 | __poll_t pevents = EPOLLIN; |
9b495a58 | 235 | |
04a5faa8 | 236 | if (shared_count == 0) |
a9a08845 | 237 | pevents |= EPOLLOUT; |
9b495a58 ML |
238 | |
239 | spin_lock_irq(&dmabuf->poll.lock); | |
240 | if (dcb->active) { | |
241 | dcb->active |= pevents; | |
242 | events &= ~pevents; | |
243 | } else | |
244 | dcb->active = pevents; | |
245 | spin_unlock_irq(&dmabuf->poll.lock); | |
246 | ||
247 | if (events & pevents) { | |
f54d1867 | 248 | if (!dma_fence_get_rcu(fence_excl)) { |
3c3b177a ML |
249 | /* force a recheck */ |
250 | events &= ~pevents; | |
251 | dma_buf_poll_cb(NULL, &dcb->cb); | |
f54d1867 CW |
252 | } else if (!dma_fence_add_callback(fence_excl, &dcb->cb, |
253 | dma_buf_poll_cb)) { | |
9b495a58 | 254 | events &= ~pevents; |
f54d1867 | 255 | dma_fence_put(fence_excl); |
04a5faa8 | 256 | } else { |
9b495a58 ML |
257 | /* |
258 | * No callback queued, wake up any additional | |
259 | * waiters. | |
260 | */ | |
f54d1867 | 261 | dma_fence_put(fence_excl); |
9b495a58 | 262 | dma_buf_poll_cb(NULL, &dcb->cb); |
04a5faa8 | 263 | } |
9b495a58 ML |
264 | } |
265 | } | |
266 | ||
a9a08845 | 267 | if ((events & EPOLLOUT) && shared_count > 0) { |
9b495a58 ML |
268 | struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_shared; |
269 | int i; | |
270 | ||
271 | /* Only queue a new callback if no event has fired yet */ | |
272 | spin_lock_irq(&dmabuf->poll.lock); | |
273 | if (dcb->active) | |
a9a08845 | 274 | events &= ~EPOLLOUT; |
9b495a58 | 275 | else |
a9a08845 | 276 | dcb->active = EPOLLOUT; |
9b495a58 ML |
277 | spin_unlock_irq(&dmabuf->poll.lock); |
278 | ||
a9a08845 | 279 | if (!(events & EPOLLOUT)) |
9b495a58 ML |
280 | goto out; |
281 | ||
04a5faa8 | 282 | for (i = 0; i < shared_count; ++i) { |
f54d1867 | 283 | struct dma_fence *fence = rcu_dereference(fobj->shared[i]); |
04a5faa8 | 284 | |
f54d1867 | 285 | if (!dma_fence_get_rcu(fence)) { |
3c3b177a ML |
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 | */ | |
a9a08845 | 292 | events &= ~EPOLLOUT; |
3c3b177a ML |
293 | dma_buf_poll_cb(NULL, &dcb->cb); |
294 | break; | |
295 | } | |
f54d1867 CW |
296 | if (!dma_fence_add_callback(fence, &dcb->cb, |
297 | dma_buf_poll_cb)) { | |
298 | dma_fence_put(fence); | |
a9a08845 | 299 | events &= ~EPOLLOUT; |
9b495a58 ML |
300 | break; |
301 | } | |
f54d1867 | 302 | dma_fence_put(fence); |
04a5faa8 | 303 | } |
9b495a58 ML |
304 | |
305 | /* No callback queued, wake up any additional waiters. */ | |
04a5faa8 | 306 | if (i == shared_count) |
9b495a58 ML |
307 | dma_buf_poll_cb(NULL, &dcb->cb); |
308 | } | |
309 | ||
310 | out: | |
3c3b177a | 311 | rcu_read_unlock(); |
9b495a58 ML |
312 | return events; |
313 | } | |
314 | ||
bb2bb903 GH |
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 | static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf) | |
331 | { | |
332 | char *name = strndup_user(buf, DMA_BUF_NAME_LEN); | |
333 | long ret = 0; | |
334 | ||
335 | if (IS_ERR(name)) | |
336 | return PTR_ERR(name); | |
337 | ||
15fd552d | 338 | dma_resv_lock(dmabuf->resv, NULL); |
bb2bb903 GH |
339 | if (!list_empty(&dmabuf->attachments)) { |
340 | ret = -EBUSY; | |
341 | kfree(name); | |
342 | goto out_unlock; | |
343 | } | |
344 | kfree(dmabuf->name); | |
345 | dmabuf->name = name; | |
346 | ||
347 | out_unlock: | |
15fd552d | 348 | dma_resv_unlock(dmabuf->resv); |
bb2bb903 GH |
349 | return ret; |
350 | } | |
351 | ||
c11e391d DV |
352 | static long dma_buf_ioctl(struct file *file, |
353 | unsigned int cmd, unsigned long arg) | |
354 | { | |
355 | struct dma_buf *dmabuf; | |
356 | struct dma_buf_sync sync; | |
357 | enum dma_data_direction direction; | |
18b862dc | 358 | int ret; |
c11e391d DV |
359 | |
360 | dmabuf = file->private_data; | |
361 | ||
362 | switch (cmd) { | |
363 | case DMA_BUF_IOCTL_SYNC: | |
364 | if (copy_from_user(&sync, (void __user *) arg, sizeof(sync))) | |
365 | return -EFAULT; | |
366 | ||
367 | if (sync.flags & ~DMA_BUF_SYNC_VALID_FLAGS_MASK) | |
368 | return -EINVAL; | |
369 | ||
370 | 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 | if (sync.flags & DMA_BUF_SYNC_END) | |
18b862dc | 385 | ret = dma_buf_end_cpu_access(dmabuf, direction); |
c11e391d | 386 | else |
18b862dc | 387 | ret = dma_buf_begin_cpu_access(dmabuf, direction); |
c11e391d | 388 | |
18b862dc | 389 | return ret; |
bb2bb903 GH |
390 | |
391 | case DMA_BUF_SET_NAME: | |
392 | return dma_buf_set_name(dmabuf, (const char __user *)arg); | |
393 | ||
c11e391d DV |
394 | default: |
395 | return -ENOTTY; | |
396 | } | |
397 | } | |
398 | ||
bcc07111 GH |
399 | static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file) |
400 | { | |
401 | struct dma_buf *dmabuf = file->private_data; | |
402 | ||
403 | seq_printf(m, "size:\t%zu\n", dmabuf->size); | |
404 | /* Don't count the temporary reference taken inside procfs seq_show */ | |
405 | seq_printf(m, "count:\t%ld\n", file_count(dmabuf->file) - 1); | |
406 | seq_printf(m, "exp_name:\t%s\n", dmabuf->exp_name); | |
15fd552d | 407 | dma_resv_lock(dmabuf->resv, NULL); |
bcc07111 GH |
408 | if (dmabuf->name) |
409 | seq_printf(m, "name:\t%s\n", dmabuf->name); | |
15fd552d | 410 | dma_resv_unlock(dmabuf->resv); |
bcc07111 GH |
411 | } |
412 | ||
d15bd7ee SS |
413 | static const struct file_operations dma_buf_fops = { |
414 | .release = dma_buf_release, | |
4c78513e | 415 | .mmap = dma_buf_mmap_internal, |
19e8697b | 416 | .llseek = dma_buf_llseek, |
9b495a58 | 417 | .poll = dma_buf_poll, |
c11e391d | 418 | .unlocked_ioctl = dma_buf_ioctl, |
1832f2d8 | 419 | .compat_ioctl = compat_ptr_ioctl, |
bcc07111 | 420 | .show_fdinfo = dma_buf_show_fdinfo, |
d15bd7ee SS |
421 | }; |
422 | ||
423 | /* | |
424 | * is_dma_buf_file - Check if struct file* is associated with dma_buf | |
425 | */ | |
426 | static inline int is_dma_buf_file(struct file *file) | |
427 | { | |
428 | return file->f_op == &dma_buf_fops; | |
429 | } | |
430 | ||
ed63bb1d GH |
431 | static struct file *dma_buf_getfile(struct dma_buf *dmabuf, int flags) |
432 | { | |
433 | struct file *file; | |
434 | struct inode *inode = alloc_anon_inode(dma_buf_mnt->mnt_sb); | |
435 | ||
436 | if (IS_ERR(inode)) | |
437 | return ERR_CAST(inode); | |
438 | ||
439 | inode->i_size = dmabuf->size; | |
440 | inode_set_bytes(inode, dmabuf->size); | |
441 | ||
442 | file = alloc_file_pseudo(inode, dma_buf_mnt, "dmabuf", | |
443 | flags, &dma_buf_fops); | |
444 | if (IS_ERR(file)) | |
445 | goto err_alloc_file; | |
446 | file->f_flags = flags & (O_ACCMODE | O_NONBLOCK); | |
447 | file->private_data = dmabuf; | |
bb2bb903 | 448 | file->f_path.dentry->d_fsdata = dmabuf; |
ed63bb1d GH |
449 | |
450 | return file; | |
451 | ||
452 | err_alloc_file: | |
453 | iput(inode); | |
454 | return file; | |
455 | } | |
456 | ||
2904a8c1 DV |
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 | |
c138782d | 470 | * dma_buf_get(). Then the buffer is attached to the device using |
2904a8c1 DV |
471 | * dma_buf_attach(). |
472 | * | |
473 | * Up to this stage the exporter is still free to migrate or reallocate the | |
474 | * backing storage. | |
475 | * | |
c138782d | 476 | * 3. Once the buffer is attached to all devices userspace can initiate DMA |
2904a8c1 DV |
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 | ||
d15bd7ee | 488 | /** |
d8fbe341 | 489 | * dma_buf_export - Creates a new dma_buf, and associates an anon file |
d15bd7ee SS |
490 | * with this buffer, so it can be exported. |
491 | * Also connect the allocator specific data and ops to the buffer. | |
78df9695 | 492 | * Additionally, provide a name string for exporter; useful in debugging. |
d15bd7ee | 493 | * |
d8fbe341 | 494 | * @exp_info: [in] holds all the export related information provided |
f641d3b5 | 495 | * by the exporter. see &struct dma_buf_export_info |
d8fbe341 | 496 | * for further details. |
d15bd7ee SS |
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 | * | |
2904a8c1 DV |
502 | * For most cases the easiest way to create @exp_info is through the |
503 | * %DEFINE_DMA_BUF_EXPORT_INFO macro. | |
d15bd7ee | 504 | */ |
d8fbe341 | 505 | struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) |
d15bd7ee SS |
506 | { |
507 | struct dma_buf *dmabuf; | |
52791eee | 508 | struct dma_resv *resv = exp_info->resv; |
d15bd7ee | 509 | struct file *file; |
3aac4502 | 510 | size_t alloc_size = sizeof(struct dma_buf); |
a026df4c | 511 | int ret; |
5136629d | 512 | |
d8fbe341 | 513 | if (!exp_info->resv) |
52791eee | 514 | alloc_size += sizeof(struct dma_resv); |
3aac4502 ML |
515 | else |
516 | /* prevent &dma_buf[1] == dma_buf->resv */ | |
517 | alloc_size += 1; | |
d15bd7ee | 518 | |
d8fbe341 SS |
519 | if (WARN_ON(!exp_info->priv |
520 | || !exp_info->ops | |
521 | || !exp_info->ops->map_dma_buf | |
522 | || !exp_info->ops->unmap_dma_buf | |
e3a9d6c5 | 523 | || !exp_info->ops->release)) { |
d15bd7ee SS |
524 | return ERR_PTR(-EINVAL); |
525 | } | |
526 | ||
15fd552d CK |
527 | if (WARN_ON(exp_info->ops->cache_sgt_mapping && |
528 | exp_info->ops->dynamic_mapping)) | |
529 | return ERR_PTR(-EINVAL); | |
530 | ||
9abdffe2 SS |
531 | if (!try_module_get(exp_info->owner)) |
532 | return ERR_PTR(-ENOENT); | |
533 | ||
3aac4502 | 534 | dmabuf = kzalloc(alloc_size, GFP_KERNEL); |
9abdffe2 | 535 | if (!dmabuf) { |
a026df4c CW |
536 | ret = -ENOMEM; |
537 | goto err_module; | |
9abdffe2 | 538 | } |
d15bd7ee | 539 | |
d8fbe341 SS |
540 | dmabuf->priv = exp_info->priv; |
541 | dmabuf->ops = exp_info->ops; | |
542 | dmabuf->size = exp_info->size; | |
543 | dmabuf->exp_name = exp_info->exp_name; | |
9abdffe2 | 544 | dmabuf->owner = exp_info->owner; |
9b495a58 ML |
545 | init_waitqueue_head(&dmabuf->poll); |
546 | dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll; | |
547 | dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0; | |
548 | ||
3aac4502 | 549 | if (!resv) { |
52791eee CK |
550 | resv = (struct dma_resv *)&dmabuf[1]; |
551 | dma_resv_init(resv); | |
3aac4502 ML |
552 | } |
553 | dmabuf->resv = resv; | |
d15bd7ee | 554 | |
ed63bb1d | 555 | file = dma_buf_getfile(dmabuf, exp_info->flags); |
9022e24e | 556 | if (IS_ERR(file)) { |
a026df4c CW |
557 | ret = PTR_ERR(file); |
558 | goto err_dmabuf; | |
9022e24e | 559 | } |
19e8697b CJHR |
560 | |
561 | file->f_mode |= FMODE_LSEEK; | |
d15bd7ee SS |
562 | dmabuf->file = file; |
563 | ||
564 | mutex_init(&dmabuf->lock); | |
565 | INIT_LIST_HEAD(&dmabuf->attachments); | |
566 | ||
b89e3563 SS |
567 | mutex_lock(&db_list.lock); |
568 | list_add(&dmabuf->list_node, &db_list.head); | |
569 | mutex_unlock(&db_list.lock); | |
570 | ||
d15bd7ee | 571 | return dmabuf; |
a026df4c CW |
572 | |
573 | err_dmabuf: | |
574 | kfree(dmabuf); | |
575 | err_module: | |
576 | module_put(exp_info->owner); | |
577 | return ERR_PTR(ret); | |
d15bd7ee | 578 | } |
d8fbe341 | 579 | EXPORT_SYMBOL_GPL(dma_buf_export); |
d15bd7ee SS |
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. | |
55c1c4ca | 584 | * @flags: [in] flags to give to fd |
d15bd7ee SS |
585 | * |
586 | * On success, returns an associated 'fd'. Else, returns error. | |
587 | */ | |
55c1c4ca | 588 | int dma_buf_fd(struct dma_buf *dmabuf, int flags) |
d15bd7ee | 589 | { |
f5e097f0 | 590 | int fd; |
d15bd7ee SS |
591 | |
592 | if (!dmabuf || !dmabuf->file) | |
593 | return -EINVAL; | |
594 | ||
f5e097f0 BP |
595 | fd = get_unused_fd_flags(flags); |
596 | if (fd < 0) | |
597 | return fd; | |
d15bd7ee SS |
598 | |
599 | fd_install(fd, dmabuf->file); | |
600 | ||
601 | 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 | struct dma_buf *dma_buf_get(int fd) | |
614 | { | |
615 | struct file *file; | |
616 | ||
617 | file = fget(fd); | |
618 | ||
619 | if (!file) | |
620 | return ERR_PTR(-EBADF); | |
621 | ||
622 | if (!is_dma_buf_file(file)) { | |
623 | fput(file); | |
624 | return ERR_PTR(-EINVAL); | |
625 | } | |
626 | ||
627 | 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 | * | |
2904a8c1 DV |
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 | |
e9b4d7b5 DV |
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. | |
d15bd7ee SS |
640 | */ |
641 | void dma_buf_put(struct dma_buf *dmabuf) | |
642 | { | |
643 | if (WARN_ON(!dmabuf || !dmabuf->file)) | |
644 | return; | |
645 | ||
646 | fput(dmabuf->file); | |
647 | } | |
648 | EXPORT_SYMBOL_GPL(dma_buf_put); | |
649 | ||
650 | /** | |
15fd552d | 651 | * dma_buf_dynamic_attach - Add the device to dma_buf's attachments list; optionally, |
d15bd7ee | 652 | * calls attach() of dma_buf_ops to allow device-specific attach functionality |
15fd552d CK |
653 | * @dmabuf: [in] buffer to attach device to. |
654 | * @dev: [in] device to be attached. | |
655 | * @dynamic_mapping: [in] calling convention for map/unmap | |
d15bd7ee | 656 | * |
2904a8c1 DV |
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. | |
d15bd7ee | 668 | */ |
15fd552d CK |
669 | struct dma_buf_attachment * |
670 | dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, | |
671 | bool dynamic_mapping) | |
d15bd7ee SS |
672 | { |
673 | struct dma_buf_attachment *attach; | |
674 | int ret; | |
675 | ||
d1aa06a1 | 676 | if (WARN_ON(!dmabuf || !dev)) |
d15bd7ee SS |
677 | return ERR_PTR(-EINVAL); |
678 | ||
db7942b6 | 679 | attach = kzalloc(sizeof(*attach), GFP_KERNEL); |
34d84ec4 | 680 | if (!attach) |
a9fbc3b7 | 681 | return ERR_PTR(-ENOMEM); |
d15bd7ee | 682 | |
d15bd7ee SS |
683 | attach->dev = dev; |
684 | attach->dmabuf = dmabuf; | |
15fd552d | 685 | attach->dynamic_mapping = dynamic_mapping; |
2ed9201b | 686 | |
d15bd7ee | 687 | if (dmabuf->ops->attach) { |
a19741e5 | 688 | ret = dmabuf->ops->attach(dmabuf, attach); |
d15bd7ee SS |
689 | if (ret) |
690 | goto err_attach; | |
691 | } | |
15fd552d | 692 | dma_resv_lock(dmabuf->resv, NULL); |
d15bd7ee | 693 | list_add(&attach->node, &dmabuf->attachments); |
15fd552d | 694 | dma_resv_unlock(dmabuf->resv); |
d15bd7ee | 695 | |
15fd552d CK |
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 | if (dma_buf_attachment_is_dynamic(attach) != | |
701 | dma_buf_is_dynamic(dmabuf)) { | |
702 | struct sg_table *sgt; | |
703 | ||
704 | if (dma_buf_is_dynamic(attach->dmabuf)) | |
705 | dma_resv_lock(attach->dmabuf->resv, NULL); | |
706 | ||
707 | sgt = dmabuf->ops->map_dma_buf(attach, DMA_BIDIRECTIONAL); | |
708 | if (!sgt) | |
709 | sgt = ERR_PTR(-ENOMEM); | |
710 | if (IS_ERR(sgt)) { | |
711 | ret = PTR_ERR(sgt); | |
712 | goto err_unlock; | |
713 | } | |
714 | if (dma_buf_is_dynamic(attach->dmabuf)) | |
715 | dma_resv_unlock(attach->dmabuf->resv); | |
716 | attach->sgt = sgt; | |
717 | attach->dir = DMA_BIDIRECTIONAL; | |
718 | } | |
719 | ||
d15bd7ee SS |
720 | return attach; |
721 | ||
d15bd7ee SS |
722 | err_attach: |
723 | kfree(attach); | |
d15bd7ee | 724 | return ERR_PTR(ret); |
15fd552d CK |
725 | |
726 | err_unlock: | |
727 | if (dma_buf_is_dynamic(attach->dmabuf)) | |
728 | dma_resv_unlock(attach->dmabuf->resv); | |
729 | ||
730 | dma_buf_detach(dmabuf, attach); | |
731 | 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 | struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, | |
744 | struct device *dev) | |
745 | { | |
746 | return dma_buf_dynamic_attach(dmabuf, dev, false); | |
d15bd7ee SS |
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 | * | |
2904a8c1 | 756 | * Clean up a device attachment obtained by calling dma_buf_attach(). |
d15bd7ee SS |
757 | */ |
758 | void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) | |
759 | { | |
d1aa06a1 | 760 | if (WARN_ON(!dmabuf || !attach)) |
d15bd7ee SS |
761 | return; |
762 | ||
15fd552d CK |
763 | if (attach->sgt) { |
764 | if (dma_buf_is_dynamic(attach->dmabuf)) | |
765 | dma_resv_lock(attach->dmabuf->resv, NULL); | |
766 | ||
f13e143e CK |
767 | dmabuf->ops->unmap_dma_buf(attach, attach->sgt, attach->dir); |
768 | ||
15fd552d CK |
769 | if (dma_buf_is_dynamic(attach->dmabuf)) |
770 | dma_resv_unlock(attach->dmabuf->resv); | |
771 | } | |
772 | ||
15fd552d | 773 | dma_resv_lock(dmabuf->resv, NULL); |
d15bd7ee | 774 | list_del(&attach->node); |
15fd552d | 775 | dma_resv_unlock(dmabuf->resv); |
d15bd7ee SS |
776 | if (dmabuf->ops->detach) |
777 | dmabuf->ops->detach(dmabuf, attach); | |
778 | ||
d15bd7ee SS |
779 | 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 | * | |
fee0c54e | 790 | * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR |
2904a8c1 DV |
791 | * on error. May return -EINTR if it is interrupted by a signal. |
792 | * | |
c138782d | 793 | * A mapping must be unmapped by using dma_buf_unmap_attachment(). Note that |
2904a8c1 DV |
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. | |
d15bd7ee SS |
797 | */ |
798 | struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, | |
799 | enum dma_data_direction direction) | |
800 | { | |
531beb06 | 801 | struct sg_table *sg_table; |
d15bd7ee SS |
802 | |
803 | might_sleep(); | |
804 | ||
d1aa06a1 | 805 | if (WARN_ON(!attach || !attach->dmabuf)) |
d15bd7ee SS |
806 | return ERR_PTR(-EINVAL); |
807 | ||
15fd552d CK |
808 | if (dma_buf_attachment_is_dynamic(attach)) |
809 | dma_resv_assert_held(attach->dmabuf->resv); | |
810 | ||
f13e143e CK |
811 | if (attach->sgt) { |
812 | /* | |
813 | * Two mappings with different directions for the same | |
814 | * attachment are not allowed. | |
815 | */ | |
816 | if (attach->dir != direction && | |
817 | attach->dir != DMA_BIDIRECTIONAL) | |
818 | return ERR_PTR(-EBUSY); | |
819 | ||
820 | return attach->sgt; | |
821 | } | |
822 | ||
15fd552d CK |
823 | if (dma_buf_is_dynamic(attach->dmabuf)) |
824 | dma_resv_assert_held(attach->dmabuf->resv); | |
825 | ||
d1aa06a1 | 826 | sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction); |
fee0c54e CC |
827 | if (!sg_table) |
828 | sg_table = ERR_PTR(-ENOMEM); | |
d15bd7ee | 829 | |
f13e143e CK |
830 | if (!IS_ERR(sg_table) && attach->dmabuf->ops->cache_sgt_mapping) { |
831 | attach->sgt = sg_table; | |
832 | attach->dir = direction; | |
833 | } | |
834 | ||
d15bd7ee SS |
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 | |
33ea2dcb | 845 | * @direction: [in] direction of DMA transfer |
d15bd7ee | 846 | * |
2904a8c1 | 847 | * This unmaps a DMA mapping for @attached obtained by dma_buf_map_attachment(). |
d15bd7ee SS |
848 | */ |
849 | void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, | |
33ea2dcb SS |
850 | struct sg_table *sg_table, |
851 | enum dma_data_direction direction) | |
d15bd7ee | 852 | { |
b6fa0cd6 RC |
853 | might_sleep(); |
854 | ||
d1aa06a1 | 855 | if (WARN_ON(!attach || !attach->dmabuf || !sg_table)) |
d15bd7ee SS |
856 | return; |
857 | ||
15fd552d CK |
858 | if (dma_buf_attachment_is_dynamic(attach)) |
859 | dma_resv_assert_held(attach->dmabuf->resv); | |
860 | ||
f13e143e CK |
861 | if (attach->sgt == sg_table) |
862 | return; | |
863 | ||
15fd552d CK |
864 | if (dma_buf_is_dynamic(attach->dmabuf)) |
865 | dma_resv_assert_held(attach->dmabuf->resv); | |
866 | ||
f13e143e | 867 | attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction); |
d15bd7ee SS |
868 | } |
869 | EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment); | |
fc13020e | 870 | |
0959a168 DV |
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 | * | |
7f0de8d8 DV |
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. | |
0959a168 DV |
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 | ||
ae4e46b1 CW |
955 | static int __dma_buf_begin_cpu_access(struct dma_buf *dmabuf, |
956 | enum dma_data_direction direction) | |
957 | { | |
958 | bool write = (direction == DMA_BIDIRECTIONAL || | |
959 | direction == DMA_TO_DEVICE); | |
52791eee | 960 | struct dma_resv *resv = dmabuf->resv; |
ae4e46b1 CW |
961 | long ret; |
962 | ||
963 | /* Wait on any implicit rendering fences */ | |
52791eee | 964 | ret = dma_resv_wait_timeout_rcu(resv, write, true, |
ae4e46b1 CW |
965 | MAX_SCHEDULE_TIMEOUT); |
966 | if (ret < 0) | |
967 | return ret; | |
968 | ||
969 | return 0; | |
970 | } | |
fc13020e DV |
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. | |
efb4df82 | 977 | * @dmabuf: [in] buffer to prepare cpu access for. |
fc13020e DV |
978 | * @direction: [in] length of range for cpu access. |
979 | * | |
0959a168 DV |
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 | * | |
fc13020e DV |
984 | * Can return negative error values, returns 0 on success. |
985 | */ | |
831e9da7 | 986 | int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, |
fc13020e DV |
987 | enum dma_data_direction direction) |
988 | { | |
989 | int ret = 0; | |
990 | ||
991 | if (WARN_ON(!dmabuf)) | |
992 | return -EINVAL; | |
993 | ||
994 | if (dmabuf->ops->begin_cpu_access) | |
831e9da7 | 995 | ret = dmabuf->ops->begin_cpu_access(dmabuf, direction); |
fc13020e | 996 | |
ae4e46b1 CW |
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 | if (ret == 0) | |
1002 | ret = __dma_buf_begin_cpu_access(dmabuf, direction); | |
1003 | ||
fc13020e DV |
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. | |
efb4df82 | 1013 | * @dmabuf: [in] buffer to complete cpu access for. |
fc13020e DV |
1014 | * @direction: [in] length of range for cpu access. |
1015 | * | |
0959a168 DV |
1016 | * This terminates CPU access started with dma_buf_begin_cpu_access(). |
1017 | * | |
87e332d5 | 1018 | * Can return negative error values, returns 0 on success. |
fc13020e | 1019 | */ |
18b862dc CW |
1020 | int dma_buf_end_cpu_access(struct dma_buf *dmabuf, |
1021 | enum dma_data_direction direction) | |
fc13020e | 1022 | { |
18b862dc CW |
1023 | int ret = 0; |
1024 | ||
fc13020e DV |
1025 | WARN_ON(!dmabuf); |
1026 | ||
1027 | if (dmabuf->ops->end_cpu_access) | |
18b862dc CW |
1028 | ret = dmabuf->ops->end_cpu_access(dmabuf, direction); |
1029 | ||
1030 | return ret; | |
fc13020e DV |
1031 | } |
1032 | EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access); | |
1033 | ||
4c78513e DV |
1034 | |
1035 | /** | |
1036 | * dma_buf_mmap - Setup up a userspace mmap with the given vma | |
12c4727e | 1037 | * @dmabuf: [in] buffer that should back the vma |
4c78513e DV |
1038 | * @vma: [in] vma for the mmap |
1039 | * @pgoff: [in] offset in pages where this mmap should start within the | |
5136629d | 1040 | * dma-buf buffer. |
4c78513e DV |
1041 | * |
1042 | * This function adjusts the passed in vma so that it points at the file of the | |
ecf1dbac | 1043 | * dma_buf operation. It also adjusts the starting pgoff and does bounds |
4c78513e DV |
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 | int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, | |
1050 | unsigned long pgoff) | |
1051 | { | |
495c10cc JS |
1052 | struct file *oldfile; |
1053 | int ret; | |
1054 | ||
4c78513e DV |
1055 | if (WARN_ON(!dmabuf || !vma)) |
1056 | return -EINVAL; | |
1057 | ||
e3a9d6c5 AD |
1058 | /* check if buffer supports mmap */ |
1059 | if (!dmabuf->ops->mmap) | |
1060 | return -EINVAL; | |
1061 | ||
4c78513e | 1062 | /* check for offset overflow */ |
b02da6f8 | 1063 | if (pgoff + vma_pages(vma) < pgoff) |
4c78513e DV |
1064 | return -EOVERFLOW; |
1065 | ||
1066 | /* check for overflowing the buffer's size */ | |
b02da6f8 | 1067 | if (pgoff + vma_pages(vma) > |
4c78513e DV |
1068 | dmabuf->size >> PAGE_SHIFT) |
1069 | return -EINVAL; | |
1070 | ||
1071 | /* readjust the vma */ | |
495c10cc JS |
1072 | get_file(dmabuf->file); |
1073 | oldfile = vma->vm_file; | |
1074 | vma->vm_file = dmabuf->file; | |
4c78513e DV |
1075 | vma->vm_pgoff = pgoff; |
1076 | ||
495c10cc JS |
1077 | ret = dmabuf->ops->mmap(dmabuf, vma); |
1078 | if (ret) { | |
1079 | /* restore old parameters on failure */ | |
1080 | vma->vm_file = oldfile; | |
1081 | fput(dmabuf->file); | |
1082 | } else { | |
1083 | if (oldfile) | |
1084 | fput(oldfile); | |
1085 | } | |
1086 | return ret; | |
1087 | ||
4c78513e DV |
1088 | } |
1089 | EXPORT_SYMBOL_GPL(dma_buf_mmap); | |
98f86c9e DA |
1090 | |
1091 | /** | |
12c4727e SS |
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 | |
98f86c9e DA |
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. | |
fee0c54e CC |
1100 | * |
1101 | * Returns NULL on error. | |
98f86c9e DA |
1102 | */ |
1103 | void *dma_buf_vmap(struct dma_buf *dmabuf) | |
1104 | { | |
f00b4dad DV |
1105 | void *ptr; |
1106 | ||
98f86c9e DA |
1107 | if (WARN_ON(!dmabuf)) |
1108 | return NULL; | |
1109 | ||
f00b4dad DV |
1110 | if (!dmabuf->ops->vmap) |
1111 | return NULL; | |
1112 | ||
1113 | mutex_lock(&dmabuf->lock); | |
1114 | if (dmabuf->vmapping_counter) { | |
1115 | dmabuf->vmapping_counter++; | |
1116 | BUG_ON(!dmabuf->vmap_ptr); | |
1117 | ptr = dmabuf->vmap_ptr; | |
1118 | goto out_unlock; | |
1119 | } | |
1120 | ||
1121 | BUG_ON(dmabuf->vmap_ptr); | |
1122 | ||
1123 | ptr = dmabuf->ops->vmap(dmabuf); | |
fee0c54e CC |
1124 | if (WARN_ON_ONCE(IS_ERR(ptr))) |
1125 | ptr = NULL; | |
1126 | if (!ptr) | |
f00b4dad DV |
1127 | goto out_unlock; |
1128 | ||
1129 | dmabuf->vmap_ptr = ptr; | |
1130 | dmabuf->vmapping_counter = 1; | |
1131 | ||
1132 | out_unlock: | |
1133 | mutex_unlock(&dmabuf->lock); | |
1134 | return ptr; | |
98f86c9e DA |
1135 | } |
1136 | EXPORT_SYMBOL_GPL(dma_buf_vmap); | |
1137 | ||
1138 | /** | |
1139 | * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap. | |
12c4727e | 1140 | * @dmabuf: [in] buffer to vunmap |
6e7b4a59 | 1141 | * @vaddr: [in] vmap to vunmap |
98f86c9e DA |
1142 | */ |
1143 | void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr) | |
1144 | { | |
1145 | if (WARN_ON(!dmabuf)) | |
1146 | return; | |
1147 | ||
f00b4dad DV |
1148 | BUG_ON(!dmabuf->vmap_ptr); |
1149 | BUG_ON(dmabuf->vmapping_counter == 0); | |
1150 | BUG_ON(dmabuf->vmap_ptr != vaddr); | |
1151 | ||
1152 | mutex_lock(&dmabuf->lock); | |
1153 | if (--dmabuf->vmapping_counter == 0) { | |
1154 | if (dmabuf->ops->vunmap) | |
1155 | dmabuf->ops->vunmap(dmabuf, vaddr); | |
1156 | dmabuf->vmap_ptr = NULL; | |
1157 | } | |
1158 | mutex_unlock(&dmabuf->lock); | |
98f86c9e DA |
1159 | } |
1160 | EXPORT_SYMBOL_GPL(dma_buf_vunmap); | |
b89e3563 SS |
1161 | |
1162 | #ifdef CONFIG_DEBUG_FS | |
eb0b947e | 1163 | static int dma_buf_debug_show(struct seq_file *s, void *unused) |
b89e3563 SS |
1164 | { |
1165 | int ret; | |
1166 | struct dma_buf *buf_obj; | |
1167 | struct dma_buf_attachment *attach_obj; | |
52791eee CK |
1168 | struct dma_resv *robj; |
1169 | struct dma_resv_list *fobj; | |
5eb2c72c | 1170 | struct dma_fence *fence; |
b016cd6e | 1171 | unsigned seq; |
5eb2c72c | 1172 | int count = 0, attach_count, shared_count, i; |
b89e3563 SS |
1173 | size_t size = 0; |
1174 | ||
1175 | ret = mutex_lock_interruptible(&db_list.lock); | |
1176 | ||
1177 | if (ret) | |
1178 | return ret; | |
1179 | ||
c0b00a52 | 1180 | seq_puts(s, "\nDma-buf Objects:\n"); |
ed63bb1d GH |
1181 | seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\t%-8s\n", |
1182 | "size", "flags", "mode", "count", "ino"); | |
b89e3563 SS |
1183 | |
1184 | list_for_each_entry(buf_obj, &db_list.head, list_node) { | |
15fd552d | 1185 | |
15fd552d CK |
1186 | ret = dma_resv_lock_interruptible(buf_obj->resv, NULL); |
1187 | if (ret) | |
f45f57cc | 1188 | goto error_unlock; |
b89e3563 | 1189 | |
bb2bb903 | 1190 | seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\n", |
c0b00a52 | 1191 | buf_obj->size, |
b89e3563 | 1192 | buf_obj->file->f_flags, buf_obj->file->f_mode, |
a1f6dbac | 1193 | file_count(buf_obj->file), |
ed63bb1d | 1194 | buf_obj->exp_name, |
bb2bb903 GH |
1195 | file_inode(buf_obj->file)->i_ino, |
1196 | buf_obj->name ?: ""); | |
b89e3563 | 1197 | |
5eb2c72c | 1198 | robj = buf_obj->resv; |
b016cd6e CW |
1199 | while (true) { |
1200 | seq = read_seqcount_begin(&robj->seq); | |
1201 | rcu_read_lock(); | |
1202 | fobj = rcu_dereference(robj->fence); | |
1203 | shared_count = fobj ? fobj->shared_count : 0; | |
1204 | fence = rcu_dereference(robj->fence_excl); | |
1205 | if (!read_seqcount_retry(&robj->seq, seq)) | |
1206 | break; | |
1207 | rcu_read_unlock(); | |
1208 | } | |
5eb2c72c RK |
1209 | |
1210 | if (fence) | |
1211 | seq_printf(s, "\tExclusive fence: %s %s %ssignalled\n", | |
1212 | fence->ops->get_driver_name(fence), | |
1213 | fence->ops->get_timeline_name(fence), | |
1214 | dma_fence_is_signaled(fence) ? "" : "un"); | |
1215 | for (i = 0; i < shared_count; i++) { | |
1216 | fence = rcu_dereference(fobj->shared[i]); | |
1217 | if (!dma_fence_get_rcu(fence)) | |
1218 | continue; | |
1219 | seq_printf(s, "\tShared fence: %s %s %ssignalled\n", | |
1220 | fence->ops->get_driver_name(fence), | |
1221 | fence->ops->get_timeline_name(fence), | |
1222 | dma_fence_is_signaled(fence) ? "" : "un"); | |
5e383a97 | 1223 | dma_fence_put(fence); |
5eb2c72c RK |
1224 | } |
1225 | rcu_read_unlock(); | |
1226 | ||
c0b00a52 | 1227 | seq_puts(s, "\tAttached Devices:\n"); |
b89e3563 SS |
1228 | attach_count = 0; |
1229 | ||
1230 | list_for_each_entry(attach_obj, &buf_obj->attachments, node) { | |
9eddb41d | 1231 | seq_printf(s, "\t%s\n", dev_name(attach_obj->dev)); |
b89e3563 SS |
1232 | attach_count++; |
1233 | } | |
15fd552d | 1234 | dma_resv_unlock(buf_obj->resv); |
b89e3563 | 1235 | |
c0b00a52 | 1236 | seq_printf(s, "Total %d devices attached\n\n", |
b89e3563 SS |
1237 | attach_count); |
1238 | ||
1239 | count++; | |
1240 | size += buf_obj->size; | |
b89e3563 SS |
1241 | } |
1242 | ||
1243 | seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size); | |
1244 | ||
1245 | mutex_unlock(&db_list.lock); | |
1246 | return 0; | |
15fd552d | 1247 | |
f45f57cc | 1248 | error_unlock: |
15fd552d CK |
1249 | mutex_unlock(&db_list.lock); |
1250 | return ret; | |
b89e3563 SS |
1251 | } |
1252 | ||
2674305a | 1253 | DEFINE_SHOW_ATTRIBUTE(dma_buf_debug); |
b89e3563 SS |
1254 | |
1255 | static struct dentry *dma_buf_debugfs_dir; | |
1256 | ||
1257 | static int dma_buf_init_debugfs(void) | |
1258 | { | |
bd3e2208 | 1259 | struct dentry *d; |
b89e3563 | 1260 | int err = 0; |
5136629d | 1261 | |
bd3e2208 MK |
1262 | d = debugfs_create_dir("dma_buf", NULL); |
1263 | if (IS_ERR(d)) | |
1264 | return PTR_ERR(d); | |
5136629d | 1265 | |
bd3e2208 | 1266 | dma_buf_debugfs_dir = d; |
b89e3563 | 1267 | |
bd3e2208 MK |
1268 | d = debugfs_create_file("bufinfo", S_IRUGO, dma_buf_debugfs_dir, |
1269 | NULL, &dma_buf_debug_fops); | |
1270 | if (IS_ERR(d)) { | |
b89e3563 | 1271 | pr_debug("dma_buf: debugfs: failed to create node bufinfo\n"); |
b7479990 MK |
1272 | debugfs_remove_recursive(dma_buf_debugfs_dir); |
1273 | dma_buf_debugfs_dir = NULL; | |
bd3e2208 | 1274 | err = PTR_ERR(d); |
b7479990 | 1275 | } |
b89e3563 SS |
1276 | |
1277 | return err; | |
1278 | } | |
1279 | ||
1280 | static void dma_buf_uninit_debugfs(void) | |
1281 | { | |
298b6a81 | 1282 | debugfs_remove_recursive(dma_buf_debugfs_dir); |
b89e3563 | 1283 | } |
b89e3563 SS |
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 | static int __init dma_buf_init(void) | |
1295 | { | |
ed63bb1d GH |
1296 | dma_buf_mnt = kern_mount(&dma_buf_fs_type); |
1297 | if (IS_ERR(dma_buf_mnt)) | |
1298 | return PTR_ERR(dma_buf_mnt); | |
1299 | ||
b89e3563 SS |
1300 | mutex_init(&db_list.lock); |
1301 | INIT_LIST_HEAD(&db_list.head); | |
1302 | dma_buf_init_debugfs(); | |
1303 | return 0; | |
1304 | } | |
1305 | subsys_initcall(dma_buf_init); | |
1306 | ||
1307 | static void __exit dma_buf_deinit(void) | |
1308 | { | |
1309 | dma_buf_uninit_debugfs(); | |
ed63bb1d | 1310 | kern_unmount(dma_buf_mnt); |
b89e3563 SS |
1311 | } |
1312 | __exitcall(dma_buf_deinit); |