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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; | |
6348dd29 | 48 | spin_lock(&dmabuf->name_lock); |
bb2bb903 GH |
49 | if (dmabuf->name) |
50 | ret = strlcpy(name, dmabuf->name, DMA_BUF_NAME_LEN); | |
6348dd29 | 51 | spin_unlock(&dmabuf->name_lock); |
bb2bb903 GH |
52 | |
53 | return dynamic_dname(dentry, buffer, buflen, "/%s:%s", | |
54 | dentry->d_name.name, ret > 0 ? name : ""); | |
55 | } | |
56 | ||
4ab59c3c | 57 | static void dma_buf_release(struct dentry *dentry) |
d15bd7ee SS |
58 | { |
59 | struct dma_buf *dmabuf; | |
60 | ||
4ab59c3c | 61 | dmabuf = dentry->d_fsdata; |
19a508bd CTR |
62 | if (unlikely(!dmabuf)) |
63 | return; | |
d15bd7ee | 64 | |
f00b4dad DV |
65 | BUG_ON(dmabuf->vmapping_counter); |
66 | ||
9b495a58 ML |
67 | /* |
68 | * Any fences that a dma-buf poll can wait on should be signaled | |
69 | * before releasing dma-buf. This is the responsibility of each | |
70 | * driver that uses the reservation objects. | |
71 | * | |
72 | * If you hit this BUG() it means someone dropped their ref to the | |
73 | * dma-buf while still having pending operation to the buffer. | |
74 | */ | |
75 | BUG_ON(dmabuf->cb_shared.active || dmabuf->cb_excl.active); | |
76 | ||
d15bd7ee | 77 | dmabuf->ops->release(dmabuf); |
b89e3563 SS |
78 | |
79 | mutex_lock(&db_list.lock); | |
80 | list_del(&dmabuf->list_node); | |
81 | mutex_unlock(&db_list.lock); | |
82 | ||
52791eee CK |
83 | if (dmabuf->resv == (struct dma_resv *)&dmabuf[1]) |
84 | dma_resv_fini(dmabuf->resv); | |
3aac4502 | 85 | |
9abdffe2 | 86 | module_put(dmabuf->owner); |
d1f37226 | 87 | kfree(dmabuf->name); |
d15bd7ee | 88 | kfree(dmabuf); |
4ab59c3c SS |
89 | } |
90 | ||
91 | static const struct dentry_operations dma_buf_dentry_ops = { | |
92 | .d_dname = dmabuffs_dname, | |
93 | .d_release = dma_buf_release, | |
94 | }; | |
95 | ||
96 | static struct vfsmount *dma_buf_mnt; | |
97 | ||
98 | static int dma_buf_fs_init_context(struct fs_context *fc) | |
99 | { | |
100 | struct pseudo_fs_context *ctx; | |
101 | ||
102 | ctx = init_pseudo(fc, DMA_BUF_MAGIC); | |
103 | if (!ctx) | |
104 | return -ENOMEM; | |
105 | ctx->dops = &dma_buf_dentry_ops; | |
d15bd7ee SS |
106 | return 0; |
107 | } | |
108 | ||
4ab59c3c SS |
109 | static struct file_system_type dma_buf_fs_type = { |
110 | .name = "dmabuf", | |
111 | .init_fs_context = dma_buf_fs_init_context, | |
112 | .kill_sb = kill_anon_super, | |
113 | }; | |
114 | ||
4c78513e DV |
115 | static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) |
116 | { | |
117 | struct dma_buf *dmabuf; | |
118 | ||
119 | if (!is_dma_buf_file(file)) | |
120 | return -EINVAL; | |
121 | ||
122 | dmabuf = file->private_data; | |
123 | ||
e3a9d6c5 AD |
124 | /* check if buffer supports mmap */ |
125 | if (!dmabuf->ops->mmap) | |
126 | return -EINVAL; | |
127 | ||
4c78513e | 128 | /* check for overflowing the buffer's size */ |
b02da6f8 | 129 | if (vma->vm_pgoff + vma_pages(vma) > |
4c78513e DV |
130 | dmabuf->size >> PAGE_SHIFT) |
131 | return -EINVAL; | |
132 | ||
133 | return dmabuf->ops->mmap(dmabuf, vma); | |
134 | } | |
135 | ||
19e8697b CJHR |
136 | static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence) |
137 | { | |
138 | struct dma_buf *dmabuf; | |
139 | loff_t base; | |
140 | ||
141 | if (!is_dma_buf_file(file)) | |
142 | return -EBADF; | |
143 | ||
144 | dmabuf = file->private_data; | |
145 | ||
146 | /* only support discovering the end of the buffer, | |
147 | but also allow SEEK_SET to maintain the idiomatic | |
148 | SEEK_END(0), SEEK_CUR(0) pattern */ | |
149 | if (whence == SEEK_END) | |
150 | base = dmabuf->size; | |
151 | else if (whence == SEEK_SET) | |
152 | base = 0; | |
153 | else | |
154 | return -EINVAL; | |
155 | ||
156 | if (offset != 0) | |
157 | return -EINVAL; | |
158 | ||
159 | return base + offset; | |
160 | } | |
161 | ||
e7e21c72 | 162 | /** |
102514ec | 163 | * DOC: implicit fence polling |
e7e21c72 DV |
164 | * |
165 | * To support cross-device and cross-driver synchronization of buffer access | |
102514ec DV |
166 | * implicit fences (represented internally in the kernel with &struct dma_fence) |
167 | * can be attached to a &dma_buf. The glue for that and a few related things are | |
52791eee | 168 | * provided in the &dma_resv structure. |
e7e21c72 DV |
169 | * |
170 | * Userspace can query the state of these implicitly tracked fences using poll() | |
171 | * and related system calls: | |
172 | * | |
a9a08845 | 173 | * - Checking for EPOLLIN, i.e. read access, can be use to query the state of the |
e7e21c72 DV |
174 | * most recent write or exclusive fence. |
175 | * | |
a9a08845 | 176 | * - Checking for EPOLLOUT, i.e. write access, can be used to query the state of |
e7e21c72 DV |
177 | * all attached fences, shared and exclusive ones. |
178 | * | |
179 | * Note that this only signals the completion of the respective fences, i.e. the | |
180 | * DMA transfers are complete. Cache flushing and any other necessary | |
181 | * preparations before CPU access can begin still need to happen. | |
182 | */ | |
183 | ||
f54d1867 | 184 | static void dma_buf_poll_cb(struct dma_fence *fence, struct dma_fence_cb *cb) |
9b495a58 ML |
185 | { |
186 | struct dma_buf_poll_cb_t *dcb = (struct dma_buf_poll_cb_t *)cb; | |
187 | unsigned long flags; | |
188 | ||
189 | spin_lock_irqsave(&dcb->poll->lock, flags); | |
190 | wake_up_locked_poll(dcb->poll, dcb->active); | |
191 | dcb->active = 0; | |
192 | spin_unlock_irqrestore(&dcb->poll->lock, flags); | |
193 | } | |
194 | ||
afc9a42b | 195 | static __poll_t dma_buf_poll(struct file *file, poll_table *poll) |
9b495a58 ML |
196 | { |
197 | struct dma_buf *dmabuf; | |
52791eee CK |
198 | struct dma_resv *resv; |
199 | struct dma_resv_list *fobj; | |
f54d1867 | 200 | struct dma_fence *fence_excl; |
01699437 | 201 | __poll_t events; |
b016cd6e | 202 | unsigned shared_count, seq; |
9b495a58 ML |
203 | |
204 | dmabuf = file->private_data; | |
205 | if (!dmabuf || !dmabuf->resv) | |
a9a08845 | 206 | return EPOLLERR; |
9b495a58 ML |
207 | |
208 | resv = dmabuf->resv; | |
209 | ||
210 | poll_wait(file, &dmabuf->poll, poll); | |
211 | ||
a9a08845 | 212 | events = poll_requested_events(poll) & (EPOLLIN | EPOLLOUT); |
9b495a58 ML |
213 | if (!events) |
214 | return 0; | |
215 | ||
b016cd6e CW |
216 | retry: |
217 | seq = read_seqcount_begin(&resv->seq); | |
3c3b177a | 218 | rcu_read_lock(); |
b016cd6e CW |
219 | |
220 | fobj = rcu_dereference(resv->fence); | |
221 | if (fobj) | |
222 | shared_count = fobj->shared_count; | |
223 | else | |
224 | shared_count = 0; | |
225 | fence_excl = rcu_dereference(resv->fence_excl); | |
226 | if (read_seqcount_retry(&resv->seq, seq)) { | |
227 | rcu_read_unlock(); | |
228 | goto retry; | |
229 | } | |
230 | ||
a9a08845 | 231 | if (fence_excl && (!(events & EPOLLOUT) || shared_count == 0)) { |
9b495a58 | 232 | struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_excl; |
a9a08845 | 233 | __poll_t pevents = EPOLLIN; |
9b495a58 | 234 | |
04a5faa8 | 235 | if (shared_count == 0) |
a9a08845 | 236 | pevents |= EPOLLOUT; |
9b495a58 ML |
237 | |
238 | spin_lock_irq(&dmabuf->poll.lock); | |
239 | if (dcb->active) { | |
240 | dcb->active |= pevents; | |
241 | events &= ~pevents; | |
242 | } else | |
243 | dcb->active = pevents; | |
244 | spin_unlock_irq(&dmabuf->poll.lock); | |
245 | ||
246 | if (events & pevents) { | |
f54d1867 | 247 | if (!dma_fence_get_rcu(fence_excl)) { |
3c3b177a ML |
248 | /* force a recheck */ |
249 | events &= ~pevents; | |
250 | dma_buf_poll_cb(NULL, &dcb->cb); | |
f54d1867 CW |
251 | } else if (!dma_fence_add_callback(fence_excl, &dcb->cb, |
252 | dma_buf_poll_cb)) { | |
9b495a58 | 253 | events &= ~pevents; |
f54d1867 | 254 | dma_fence_put(fence_excl); |
04a5faa8 | 255 | } else { |
9b495a58 ML |
256 | /* |
257 | * No callback queued, wake up any additional | |
258 | * waiters. | |
259 | */ | |
f54d1867 | 260 | dma_fence_put(fence_excl); |
9b495a58 | 261 | dma_buf_poll_cb(NULL, &dcb->cb); |
04a5faa8 | 262 | } |
9b495a58 ML |
263 | } |
264 | } | |
265 | ||
a9a08845 | 266 | if ((events & EPOLLOUT) && shared_count > 0) { |
9b495a58 ML |
267 | struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_shared; |
268 | int i; | |
269 | ||
270 | /* Only queue a new callback if no event has fired yet */ | |
271 | spin_lock_irq(&dmabuf->poll.lock); | |
272 | if (dcb->active) | |
a9a08845 | 273 | events &= ~EPOLLOUT; |
9b495a58 | 274 | else |
a9a08845 | 275 | dcb->active = EPOLLOUT; |
9b495a58 ML |
276 | spin_unlock_irq(&dmabuf->poll.lock); |
277 | ||
a9a08845 | 278 | if (!(events & EPOLLOUT)) |
9b495a58 ML |
279 | goto out; |
280 | ||
04a5faa8 | 281 | for (i = 0; i < shared_count; ++i) { |
f54d1867 | 282 | struct dma_fence *fence = rcu_dereference(fobj->shared[i]); |
04a5faa8 | 283 | |
f54d1867 | 284 | if (!dma_fence_get_rcu(fence)) { |
3c3b177a ML |
285 | /* |
286 | * fence refcount dropped to zero, this means | |
287 | * that fobj has been freed | |
288 | * | |
289 | * call dma_buf_poll_cb and force a recheck! | |
290 | */ | |
a9a08845 | 291 | events &= ~EPOLLOUT; |
3c3b177a ML |
292 | dma_buf_poll_cb(NULL, &dcb->cb); |
293 | break; | |
294 | } | |
f54d1867 CW |
295 | if (!dma_fence_add_callback(fence, &dcb->cb, |
296 | dma_buf_poll_cb)) { | |
297 | dma_fence_put(fence); | |
a9a08845 | 298 | events &= ~EPOLLOUT; |
9b495a58 ML |
299 | break; |
300 | } | |
f54d1867 | 301 | dma_fence_put(fence); |
04a5faa8 | 302 | } |
9b495a58 ML |
303 | |
304 | /* No callback queued, wake up any additional waiters. */ | |
04a5faa8 | 305 | if (i == shared_count) |
9b495a58 ML |
306 | dma_buf_poll_cb(NULL, &dcb->cb); |
307 | } | |
308 | ||
309 | out: | |
3c3b177a | 310 | rcu_read_unlock(); |
9b495a58 ML |
311 | return events; |
312 | } | |
313 | ||
bb2bb903 GH |
314 | /** |
315 | * dma_buf_set_name - Set a name to a specific dma_buf to track the usage. | |
316 | * The name of the dma-buf buffer can only be set when the dma-buf is not | |
317 | * attached to any devices. It could theoritically support changing the | |
318 | * name of the dma-buf if the same piece of memory is used for multiple | |
319 | * purpose between different devices. | |
320 | * | |
6d3ba803 KK |
321 | * @dmabuf: [in] dmabuf buffer that will be renamed. |
322 | * @buf: [in] A piece of userspace memory that contains the name of | |
323 | * the dma-buf. | |
bb2bb903 GH |
324 | * |
325 | * Returns 0 on success. If the dma-buf buffer is already attached to | |
326 | * devices, return -EBUSY. | |
327 | * | |
328 | */ | |
329 | static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf) | |
330 | { | |
331 | char *name = strndup_user(buf, DMA_BUF_NAME_LEN); | |
332 | long ret = 0; | |
333 | ||
334 | if (IS_ERR(name)) | |
335 | return PTR_ERR(name); | |
336 | ||
15fd552d | 337 | dma_resv_lock(dmabuf->resv, NULL); |
bb2bb903 GH |
338 | if (!list_empty(&dmabuf->attachments)) { |
339 | ret = -EBUSY; | |
340 | kfree(name); | |
341 | goto out_unlock; | |
342 | } | |
6348dd29 | 343 | spin_lock(&dmabuf->name_lock); |
bb2bb903 GH |
344 | kfree(dmabuf->name); |
345 | dmabuf->name = name; | |
6348dd29 | 346 | spin_unlock(&dmabuf->name_lock); |
bb2bb903 GH |
347 | |
348 | out_unlock: | |
15fd552d | 349 | dma_resv_unlock(dmabuf->resv); |
bb2bb903 GH |
350 | return ret; |
351 | } | |
352 | ||
c11e391d DV |
353 | static long dma_buf_ioctl(struct file *file, |
354 | unsigned int cmd, unsigned long arg) | |
355 | { | |
356 | struct dma_buf *dmabuf; | |
357 | struct dma_buf_sync sync; | |
358 | enum dma_data_direction direction; | |
18b862dc | 359 | int ret; |
c11e391d DV |
360 | |
361 | dmabuf = file->private_data; | |
362 | ||
363 | switch (cmd) { | |
364 | case DMA_BUF_IOCTL_SYNC: | |
365 | if (copy_from_user(&sync, (void __user *) arg, sizeof(sync))) | |
366 | return -EFAULT; | |
367 | ||
368 | if (sync.flags & ~DMA_BUF_SYNC_VALID_FLAGS_MASK) | |
369 | return -EINVAL; | |
370 | ||
371 | switch (sync.flags & DMA_BUF_SYNC_RW) { | |
372 | case DMA_BUF_SYNC_READ: | |
373 | direction = DMA_FROM_DEVICE; | |
374 | break; | |
375 | case DMA_BUF_SYNC_WRITE: | |
376 | direction = DMA_TO_DEVICE; | |
377 | break; | |
378 | case DMA_BUF_SYNC_RW: | |
379 | direction = DMA_BIDIRECTIONAL; | |
380 | break; | |
381 | default: | |
382 | return -EINVAL; | |
383 | } | |
384 | ||
385 | if (sync.flags & DMA_BUF_SYNC_END) | |
18b862dc | 386 | ret = dma_buf_end_cpu_access(dmabuf, direction); |
c11e391d | 387 | else |
18b862dc | 388 | ret = dma_buf_begin_cpu_access(dmabuf, direction); |
c11e391d | 389 | |
18b862dc | 390 | return ret; |
bb2bb903 | 391 | |
a5bff92e DV |
392 | case DMA_BUF_SET_NAME_A: |
393 | case DMA_BUF_SET_NAME_B: | |
bb2bb903 GH |
394 | return dma_buf_set_name(dmabuf, (const char __user *)arg); |
395 | ||
c11e391d DV |
396 | default: |
397 | return -ENOTTY; | |
398 | } | |
399 | } | |
400 | ||
bcc07111 GH |
401 | static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file) |
402 | { | |
403 | struct dma_buf *dmabuf = file->private_data; | |
404 | ||
405 | seq_printf(m, "size:\t%zu\n", dmabuf->size); | |
406 | /* Don't count the temporary reference taken inside procfs seq_show */ | |
407 | seq_printf(m, "count:\t%ld\n", file_count(dmabuf->file) - 1); | |
408 | seq_printf(m, "exp_name:\t%s\n", dmabuf->exp_name); | |
6348dd29 | 409 | spin_lock(&dmabuf->name_lock); |
bcc07111 GH |
410 | if (dmabuf->name) |
411 | seq_printf(m, "name:\t%s\n", dmabuf->name); | |
6348dd29 | 412 | spin_unlock(&dmabuf->name_lock); |
bcc07111 GH |
413 | } |
414 | ||
d15bd7ee | 415 | static const struct file_operations dma_buf_fops = { |
4c78513e | 416 | .mmap = dma_buf_mmap_internal, |
19e8697b | 417 | .llseek = dma_buf_llseek, |
9b495a58 | 418 | .poll = dma_buf_poll, |
c11e391d | 419 | .unlocked_ioctl = dma_buf_ioctl, |
1832f2d8 | 420 | .compat_ioctl = compat_ptr_ioctl, |
bcc07111 | 421 | .show_fdinfo = dma_buf_show_fdinfo, |
d15bd7ee SS |
422 | }; |
423 | ||
424 | /* | |
425 | * is_dma_buf_file - Check if struct file* is associated with dma_buf | |
426 | */ | |
427 | static inline int is_dma_buf_file(struct file *file) | |
428 | { | |
429 | return file->f_op == &dma_buf_fops; | |
430 | } | |
431 | ||
ed63bb1d GH |
432 | static struct file *dma_buf_getfile(struct dma_buf *dmabuf, int flags) |
433 | { | |
434 | struct file *file; | |
435 | struct inode *inode = alloc_anon_inode(dma_buf_mnt->mnt_sb); | |
436 | ||
437 | if (IS_ERR(inode)) | |
438 | return ERR_CAST(inode); | |
439 | ||
440 | inode->i_size = dmabuf->size; | |
441 | inode_set_bytes(inode, dmabuf->size); | |
442 | ||
443 | file = alloc_file_pseudo(inode, dma_buf_mnt, "dmabuf", | |
444 | flags, &dma_buf_fops); | |
445 | if (IS_ERR(file)) | |
446 | goto err_alloc_file; | |
447 | file->f_flags = flags & (O_ACCMODE | O_NONBLOCK); | |
448 | file->private_data = dmabuf; | |
bb2bb903 | 449 | file->f_path.dentry->d_fsdata = dmabuf; |
ed63bb1d GH |
450 | |
451 | return file; | |
452 | ||
453 | err_alloc_file: | |
454 | iput(inode); | |
455 | return file; | |
456 | } | |
457 | ||
2904a8c1 DV |
458 | /** |
459 | * DOC: dma buf device access | |
460 | * | |
461 | * For device DMA access to a shared DMA buffer the usual sequence of operations | |
462 | * is fairly simple: | |
463 | * | |
464 | * 1. The exporter defines his exporter instance using | |
465 | * DEFINE_DMA_BUF_EXPORT_INFO() and calls dma_buf_export() to wrap a private | |
466 | * buffer object into a &dma_buf. It then exports that &dma_buf to userspace | |
467 | * as a file descriptor by calling dma_buf_fd(). | |
468 | * | |
469 | * 2. Userspace passes this file-descriptors to all drivers it wants this buffer | |
470 | * to share with: First the filedescriptor is converted to a &dma_buf using | |
c138782d | 471 | * dma_buf_get(). Then the buffer is attached to the device using |
2904a8c1 DV |
472 | * dma_buf_attach(). |
473 | * | |
474 | * Up to this stage the exporter is still free to migrate or reallocate the | |
475 | * backing storage. | |
476 | * | |
c138782d | 477 | * 3. Once the buffer is attached to all devices userspace can initiate DMA |
2904a8c1 DV |
478 | * access to the shared buffer. In the kernel this is done by calling |
479 | * dma_buf_map_attachment() and dma_buf_unmap_attachment(). | |
480 | * | |
481 | * 4. Once a driver is done with a shared buffer it needs to call | |
482 | * dma_buf_detach() (after cleaning up any mappings) and then release the | |
483 | * reference acquired with dma_buf_get by calling dma_buf_put(). | |
484 | * | |
485 | * For the detailed semantics exporters are expected to implement see | |
486 | * &dma_buf_ops. | |
487 | */ | |
488 | ||
d15bd7ee | 489 | /** |
d8fbe341 | 490 | * dma_buf_export - Creates a new dma_buf, and associates an anon file |
d15bd7ee SS |
491 | * with this buffer, so it can be exported. |
492 | * Also connect the allocator specific data and ops to the buffer. | |
78df9695 | 493 | * Additionally, provide a name string for exporter; useful in debugging. |
d15bd7ee | 494 | * |
d8fbe341 | 495 | * @exp_info: [in] holds all the export related information provided |
f641d3b5 | 496 | * by the exporter. see &struct dma_buf_export_info |
d8fbe341 | 497 | * for further details. |
d15bd7ee SS |
498 | * |
499 | * Returns, on success, a newly created dma_buf object, which wraps the | |
500 | * supplied private data and operations for dma_buf_ops. On either missing | |
501 | * ops, or error in allocating struct dma_buf, will return negative error. | |
502 | * | |
2904a8c1 DV |
503 | * For most cases the easiest way to create @exp_info is through the |
504 | * %DEFINE_DMA_BUF_EXPORT_INFO macro. | |
d15bd7ee | 505 | */ |
d8fbe341 | 506 | struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) |
d15bd7ee SS |
507 | { |
508 | struct dma_buf *dmabuf; | |
52791eee | 509 | struct dma_resv *resv = exp_info->resv; |
d15bd7ee | 510 | struct file *file; |
3aac4502 | 511 | size_t alloc_size = sizeof(struct dma_buf); |
a026df4c | 512 | int ret; |
5136629d | 513 | |
d8fbe341 | 514 | if (!exp_info->resv) |
52791eee | 515 | alloc_size += sizeof(struct dma_resv); |
3aac4502 ML |
516 | else |
517 | /* prevent &dma_buf[1] == dma_buf->resv */ | |
518 | alloc_size += 1; | |
d15bd7ee | 519 | |
d8fbe341 SS |
520 | if (WARN_ON(!exp_info->priv |
521 | || !exp_info->ops | |
522 | || !exp_info->ops->map_dma_buf | |
523 | || !exp_info->ops->unmap_dma_buf | |
e3a9d6c5 | 524 | || !exp_info->ops->release)) { |
d15bd7ee SS |
525 | return ERR_PTR(-EINVAL); |
526 | } | |
527 | ||
15fd552d | 528 | if (WARN_ON(exp_info->ops->cache_sgt_mapping && |
bd2275ee | 529 | (exp_info->ops->pin || exp_info->ops->unpin))) |
15fd552d CK |
530 | return ERR_PTR(-EINVAL); |
531 | ||
bd2275ee | 532 | if (WARN_ON(!exp_info->ops->pin != !exp_info->ops->unpin)) |
15fd552d CK |
533 | return ERR_PTR(-EINVAL); |
534 | ||
9abdffe2 SS |
535 | if (!try_module_get(exp_info->owner)) |
536 | return ERR_PTR(-ENOENT); | |
537 | ||
3aac4502 | 538 | dmabuf = kzalloc(alloc_size, GFP_KERNEL); |
9abdffe2 | 539 | if (!dmabuf) { |
a026df4c CW |
540 | ret = -ENOMEM; |
541 | goto err_module; | |
9abdffe2 | 542 | } |
d15bd7ee | 543 | |
d8fbe341 SS |
544 | dmabuf->priv = exp_info->priv; |
545 | dmabuf->ops = exp_info->ops; | |
546 | dmabuf->size = exp_info->size; | |
547 | dmabuf->exp_name = exp_info->exp_name; | |
9abdffe2 | 548 | dmabuf->owner = exp_info->owner; |
6348dd29 | 549 | spin_lock_init(&dmabuf->name_lock); |
9b495a58 ML |
550 | init_waitqueue_head(&dmabuf->poll); |
551 | dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll; | |
552 | dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0; | |
553 | ||
3aac4502 | 554 | if (!resv) { |
52791eee CK |
555 | resv = (struct dma_resv *)&dmabuf[1]; |
556 | dma_resv_init(resv); | |
3aac4502 ML |
557 | } |
558 | dmabuf->resv = resv; | |
d15bd7ee | 559 | |
ed63bb1d | 560 | file = dma_buf_getfile(dmabuf, exp_info->flags); |
9022e24e | 561 | if (IS_ERR(file)) { |
a026df4c CW |
562 | ret = PTR_ERR(file); |
563 | goto err_dmabuf; | |
9022e24e | 564 | } |
19e8697b CJHR |
565 | |
566 | file->f_mode |= FMODE_LSEEK; | |
d15bd7ee SS |
567 | dmabuf->file = file; |
568 | ||
569 | mutex_init(&dmabuf->lock); | |
570 | INIT_LIST_HEAD(&dmabuf->attachments); | |
571 | ||
b89e3563 SS |
572 | mutex_lock(&db_list.lock); |
573 | list_add(&dmabuf->list_node, &db_list.head); | |
574 | mutex_unlock(&db_list.lock); | |
575 | ||
d15bd7ee | 576 | return dmabuf; |
a026df4c CW |
577 | |
578 | err_dmabuf: | |
579 | kfree(dmabuf); | |
580 | err_module: | |
581 | module_put(exp_info->owner); | |
582 | return ERR_PTR(ret); | |
d15bd7ee | 583 | } |
d8fbe341 | 584 | EXPORT_SYMBOL_GPL(dma_buf_export); |
d15bd7ee SS |
585 | |
586 | /** | |
587 | * dma_buf_fd - returns a file descriptor for the given dma_buf | |
588 | * @dmabuf: [in] pointer to dma_buf for which fd is required. | |
55c1c4ca | 589 | * @flags: [in] flags to give to fd |
d15bd7ee SS |
590 | * |
591 | * On success, returns an associated 'fd'. Else, returns error. | |
592 | */ | |
55c1c4ca | 593 | int dma_buf_fd(struct dma_buf *dmabuf, int flags) |
d15bd7ee | 594 | { |
f5e097f0 | 595 | int fd; |
d15bd7ee SS |
596 | |
597 | if (!dmabuf || !dmabuf->file) | |
598 | return -EINVAL; | |
599 | ||
f5e097f0 BP |
600 | fd = get_unused_fd_flags(flags); |
601 | if (fd < 0) | |
602 | return fd; | |
d15bd7ee SS |
603 | |
604 | fd_install(fd, dmabuf->file); | |
605 | ||
606 | return fd; | |
607 | } | |
608 | EXPORT_SYMBOL_GPL(dma_buf_fd); | |
609 | ||
610 | /** | |
611 | * dma_buf_get - returns the dma_buf structure related to an fd | |
612 | * @fd: [in] fd associated with the dma_buf to be returned | |
613 | * | |
614 | * On success, returns the dma_buf structure associated with an fd; uses | |
615 | * file's refcounting done by fget to increase refcount. returns ERR_PTR | |
616 | * otherwise. | |
617 | */ | |
618 | struct dma_buf *dma_buf_get(int fd) | |
619 | { | |
620 | struct file *file; | |
621 | ||
622 | file = fget(fd); | |
623 | ||
624 | if (!file) | |
625 | return ERR_PTR(-EBADF); | |
626 | ||
627 | if (!is_dma_buf_file(file)) { | |
628 | fput(file); | |
629 | return ERR_PTR(-EINVAL); | |
630 | } | |
631 | ||
632 | return file->private_data; | |
633 | } | |
634 | EXPORT_SYMBOL_GPL(dma_buf_get); | |
635 | ||
636 | /** | |
637 | * dma_buf_put - decreases refcount of the buffer | |
638 | * @dmabuf: [in] buffer to reduce refcount of | |
639 | * | |
2904a8c1 DV |
640 | * Uses file's refcounting done implicitly by fput(). |
641 | * | |
642 | * If, as a result of this call, the refcount becomes 0, the 'release' file | |
e9b4d7b5 DV |
643 | * operation related to this fd is called. It calls &dma_buf_ops.release vfunc |
644 | * in turn, and frees the memory allocated for dmabuf when exported. | |
d15bd7ee SS |
645 | */ |
646 | void dma_buf_put(struct dma_buf *dmabuf) | |
647 | { | |
648 | if (WARN_ON(!dmabuf || !dmabuf->file)) | |
649 | return; | |
650 | ||
651 | fput(dmabuf->file); | |
652 | } | |
653 | EXPORT_SYMBOL_GPL(dma_buf_put); | |
654 | ||
655 | /** | |
15fd552d | 656 | * dma_buf_dynamic_attach - Add the device to dma_buf's attachments list; optionally, |
d15bd7ee | 657 | * calls attach() of dma_buf_ops to allow device-specific attach functionality |
15fd552d CK |
658 | * @dmabuf: [in] buffer to attach device to. |
659 | * @dev: [in] device to be attached. | |
6f49c251 RD |
660 | * @importer_ops: [in] importer operations for the attachment |
661 | * @importer_priv: [in] importer private pointer for the attachment | |
d15bd7ee | 662 | * |
2904a8c1 DV |
663 | * Returns struct dma_buf_attachment pointer for this attachment. Attachments |
664 | * must be cleaned up by calling dma_buf_detach(). | |
665 | * | |
666 | * Returns: | |
667 | * | |
668 | * A pointer to newly created &dma_buf_attachment on success, or a negative | |
669 | * error code wrapped into a pointer on failure. | |
670 | * | |
671 | * Note that this can fail if the backing storage of @dmabuf is in a place not | |
672 | * accessible to @dev, and cannot be moved to a more suitable place. This is | |
673 | * indicated with the error code -EBUSY. | |
d15bd7ee | 674 | */ |
15fd552d CK |
675 | struct dma_buf_attachment * |
676 | dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, | |
bb42df46 CK |
677 | const struct dma_buf_attach_ops *importer_ops, |
678 | void *importer_priv) | |
d15bd7ee SS |
679 | { |
680 | struct dma_buf_attachment *attach; | |
681 | int ret; | |
682 | ||
d1aa06a1 | 683 | if (WARN_ON(!dmabuf || !dev)) |
d15bd7ee SS |
684 | return ERR_PTR(-EINVAL); |
685 | ||
4981cdb0 CK |
686 | if (WARN_ON(importer_ops && !importer_ops->move_notify)) |
687 | return ERR_PTR(-EINVAL); | |
688 | ||
db7942b6 | 689 | attach = kzalloc(sizeof(*attach), GFP_KERNEL); |
34d84ec4 | 690 | if (!attach) |
a9fbc3b7 | 691 | return ERR_PTR(-ENOMEM); |
d15bd7ee | 692 | |
d15bd7ee SS |
693 | attach->dev = dev; |
694 | attach->dmabuf = dmabuf; | |
09606b54 CK |
695 | if (importer_ops) |
696 | attach->peer2peer = importer_ops->allow_peer2peer; | |
bb42df46 CK |
697 | attach->importer_ops = importer_ops; |
698 | attach->importer_priv = importer_priv; | |
2ed9201b | 699 | |
d15bd7ee | 700 | if (dmabuf->ops->attach) { |
a19741e5 | 701 | ret = dmabuf->ops->attach(dmabuf, attach); |
d15bd7ee SS |
702 | if (ret) |
703 | goto err_attach; | |
704 | } | |
15fd552d | 705 | dma_resv_lock(dmabuf->resv, NULL); |
d15bd7ee | 706 | list_add(&attach->node, &dmabuf->attachments); |
15fd552d | 707 | dma_resv_unlock(dmabuf->resv); |
d15bd7ee | 708 | |
15fd552d CK |
709 | /* When either the importer or the exporter can't handle dynamic |
710 | * mappings we cache the mapping here to avoid issues with the | |
711 | * reservation object lock. | |
712 | */ | |
713 | if (dma_buf_attachment_is_dynamic(attach) != | |
714 | dma_buf_is_dynamic(dmabuf)) { | |
715 | struct sg_table *sgt; | |
716 | ||
bb42df46 | 717 | if (dma_buf_is_dynamic(attach->dmabuf)) { |
15fd552d | 718 | dma_resv_lock(attach->dmabuf->resv, NULL); |
bb42df46 CK |
719 | ret = dma_buf_pin(attach); |
720 | if (ret) | |
721 | goto err_unlock; | |
722 | } | |
15fd552d CK |
723 | |
724 | sgt = dmabuf->ops->map_dma_buf(attach, DMA_BIDIRECTIONAL); | |
725 | if (!sgt) | |
726 | sgt = ERR_PTR(-ENOMEM); | |
727 | if (IS_ERR(sgt)) { | |
728 | ret = PTR_ERR(sgt); | |
bb42df46 | 729 | goto err_unpin; |
15fd552d CK |
730 | } |
731 | if (dma_buf_is_dynamic(attach->dmabuf)) | |
732 | dma_resv_unlock(attach->dmabuf->resv); | |
733 | attach->sgt = sgt; | |
734 | attach->dir = DMA_BIDIRECTIONAL; | |
735 | } | |
736 | ||
d15bd7ee SS |
737 | return attach; |
738 | ||
d15bd7ee SS |
739 | err_attach: |
740 | kfree(attach); | |
d15bd7ee | 741 | return ERR_PTR(ret); |
15fd552d | 742 | |
bb42df46 CK |
743 | err_unpin: |
744 | if (dma_buf_is_dynamic(attach->dmabuf)) | |
745 | dma_buf_unpin(attach); | |
746 | ||
15fd552d CK |
747 | err_unlock: |
748 | if (dma_buf_is_dynamic(attach->dmabuf)) | |
749 | dma_resv_unlock(attach->dmabuf->resv); | |
750 | ||
751 | dma_buf_detach(dmabuf, attach); | |
752 | return ERR_PTR(ret); | |
753 | } | |
754 | EXPORT_SYMBOL_GPL(dma_buf_dynamic_attach); | |
755 | ||
756 | /** | |
757 | * dma_buf_attach - Wrapper for dma_buf_dynamic_attach | |
758 | * @dmabuf: [in] buffer to attach device to. | |
759 | * @dev: [in] device to be attached. | |
760 | * | |
761 | * Wrapper to call dma_buf_dynamic_attach() for drivers which still use a static | |
762 | * mapping. | |
763 | */ | |
764 | struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, | |
765 | struct device *dev) | |
766 | { | |
bb42df46 | 767 | return dma_buf_dynamic_attach(dmabuf, dev, NULL, NULL); |
d15bd7ee SS |
768 | } |
769 | EXPORT_SYMBOL_GPL(dma_buf_attach); | |
770 | ||
771 | /** | |
772 | * dma_buf_detach - Remove the given attachment from dmabuf's attachments list; | |
773 | * optionally calls detach() of dma_buf_ops for device-specific detach | |
774 | * @dmabuf: [in] buffer to detach from. | |
775 | * @attach: [in] attachment to be detached; is free'd after this call. | |
776 | * | |
2904a8c1 | 777 | * Clean up a device attachment obtained by calling dma_buf_attach(). |
d15bd7ee SS |
778 | */ |
779 | void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) | |
780 | { | |
d1aa06a1 | 781 | if (WARN_ON(!dmabuf || !attach)) |
d15bd7ee SS |
782 | return; |
783 | ||
15fd552d CK |
784 | if (attach->sgt) { |
785 | if (dma_buf_is_dynamic(attach->dmabuf)) | |
786 | dma_resv_lock(attach->dmabuf->resv, NULL); | |
787 | ||
f13e143e CK |
788 | dmabuf->ops->unmap_dma_buf(attach, attach->sgt, attach->dir); |
789 | ||
bb42df46 CK |
790 | if (dma_buf_is_dynamic(attach->dmabuf)) { |
791 | dma_buf_unpin(attach); | |
15fd552d | 792 | dma_resv_unlock(attach->dmabuf->resv); |
bb42df46 | 793 | } |
15fd552d CK |
794 | } |
795 | ||
15fd552d | 796 | dma_resv_lock(dmabuf->resv, NULL); |
d15bd7ee | 797 | list_del(&attach->node); |
15fd552d | 798 | dma_resv_unlock(dmabuf->resv); |
d15bd7ee SS |
799 | if (dmabuf->ops->detach) |
800 | dmabuf->ops->detach(dmabuf, attach); | |
801 | ||
d15bd7ee SS |
802 | kfree(attach); |
803 | } | |
804 | EXPORT_SYMBOL_GPL(dma_buf_detach); | |
805 | ||
bb42df46 CK |
806 | /** |
807 | * dma_buf_pin - Lock down the DMA-buf | |
808 | * | |
809 | * @attach: [in] attachment which should be pinned | |
810 | * | |
811 | * Returns: | |
812 | * 0 on success, negative error code on failure. | |
813 | */ | |
814 | int dma_buf_pin(struct dma_buf_attachment *attach) | |
815 | { | |
816 | struct dma_buf *dmabuf = attach->dmabuf; | |
817 | int ret = 0; | |
818 | ||
819 | dma_resv_assert_held(dmabuf->resv); | |
820 | ||
821 | if (dmabuf->ops->pin) | |
822 | ret = dmabuf->ops->pin(attach); | |
823 | ||
824 | return ret; | |
825 | } | |
826 | EXPORT_SYMBOL_GPL(dma_buf_pin); | |
827 | ||
828 | /** | |
829 | * dma_buf_unpin - Remove lock from DMA-buf | |
830 | * | |
831 | * @attach: [in] attachment which should be unpinned | |
832 | */ | |
833 | void dma_buf_unpin(struct dma_buf_attachment *attach) | |
834 | { | |
835 | struct dma_buf *dmabuf = attach->dmabuf; | |
836 | ||
837 | dma_resv_assert_held(dmabuf->resv); | |
838 | ||
839 | if (dmabuf->ops->unpin) | |
840 | dmabuf->ops->unpin(attach); | |
841 | } | |
842 | EXPORT_SYMBOL_GPL(dma_buf_unpin); | |
843 | ||
d15bd7ee SS |
844 | /** |
845 | * dma_buf_map_attachment - Returns the scatterlist table of the attachment; | |
846 | * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the | |
847 | * dma_buf_ops. | |
848 | * @attach: [in] attachment whose scatterlist is to be returned | |
849 | * @direction: [in] direction of DMA transfer | |
850 | * | |
fee0c54e | 851 | * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR |
2904a8c1 DV |
852 | * on error. May return -EINTR if it is interrupted by a signal. |
853 | * | |
c138782d | 854 | * A mapping must be unmapped by using dma_buf_unmap_attachment(). Note that |
2904a8c1 DV |
855 | * the underlying backing storage is pinned for as long as a mapping exists, |
856 | * therefore users/importers should not hold onto a mapping for undue amounts of | |
857 | * time. | |
d15bd7ee SS |
858 | */ |
859 | struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, | |
860 | enum dma_data_direction direction) | |
861 | { | |
531beb06 | 862 | struct sg_table *sg_table; |
bb42df46 | 863 | int r; |
d15bd7ee SS |
864 | |
865 | might_sleep(); | |
866 | ||
d1aa06a1 | 867 | if (WARN_ON(!attach || !attach->dmabuf)) |
d15bd7ee SS |
868 | return ERR_PTR(-EINVAL); |
869 | ||
15fd552d CK |
870 | if (dma_buf_attachment_is_dynamic(attach)) |
871 | dma_resv_assert_held(attach->dmabuf->resv); | |
872 | ||
f13e143e CK |
873 | if (attach->sgt) { |
874 | /* | |
875 | * Two mappings with different directions for the same | |
876 | * attachment are not allowed. | |
877 | */ | |
878 | if (attach->dir != direction && | |
879 | attach->dir != DMA_BIDIRECTIONAL) | |
880 | return ERR_PTR(-EBUSY); | |
881 | ||
882 | return attach->sgt; | |
883 | } | |
884 | ||
bb42df46 | 885 | if (dma_buf_is_dynamic(attach->dmabuf)) { |
15fd552d | 886 | dma_resv_assert_held(attach->dmabuf->resv); |
4981cdb0 | 887 | if (!IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY)) { |
bb42df46 CK |
888 | r = dma_buf_pin(attach); |
889 | if (r) | |
890 | return ERR_PTR(r); | |
891 | } | |
892 | } | |
15fd552d | 893 | |
d1aa06a1 | 894 | sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction); |
fee0c54e CC |
895 | if (!sg_table) |
896 | sg_table = ERR_PTR(-ENOMEM); | |
d15bd7ee | 897 | |
bb42df46 | 898 | if (IS_ERR(sg_table) && dma_buf_is_dynamic(attach->dmabuf) && |
4981cdb0 | 899 | !IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY)) |
bb42df46 CK |
900 | dma_buf_unpin(attach); |
901 | ||
f13e143e CK |
902 | if (!IS_ERR(sg_table) && attach->dmabuf->ops->cache_sgt_mapping) { |
903 | attach->sgt = sg_table; | |
904 | attach->dir = direction; | |
905 | } | |
906 | ||
d15bd7ee SS |
907 | return sg_table; |
908 | } | |
909 | EXPORT_SYMBOL_GPL(dma_buf_map_attachment); | |
910 | ||
911 | /** | |
912 | * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might | |
913 | * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of | |
914 | * dma_buf_ops. | |
915 | * @attach: [in] attachment to unmap buffer from | |
916 | * @sg_table: [in] scatterlist info of the buffer to unmap | |
33ea2dcb | 917 | * @direction: [in] direction of DMA transfer |
d15bd7ee | 918 | * |
2904a8c1 | 919 | * This unmaps a DMA mapping for @attached obtained by dma_buf_map_attachment(). |
d15bd7ee SS |
920 | */ |
921 | void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, | |
33ea2dcb SS |
922 | struct sg_table *sg_table, |
923 | enum dma_data_direction direction) | |
d15bd7ee | 924 | { |
b6fa0cd6 RC |
925 | might_sleep(); |
926 | ||
d1aa06a1 | 927 | if (WARN_ON(!attach || !attach->dmabuf || !sg_table)) |
d15bd7ee SS |
928 | return; |
929 | ||
15fd552d CK |
930 | if (dma_buf_attachment_is_dynamic(attach)) |
931 | dma_resv_assert_held(attach->dmabuf->resv); | |
932 | ||
f13e143e CK |
933 | if (attach->sgt == sg_table) |
934 | return; | |
935 | ||
15fd552d CK |
936 | if (dma_buf_is_dynamic(attach->dmabuf)) |
937 | dma_resv_assert_held(attach->dmabuf->resv); | |
938 | ||
f13e143e | 939 | attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction); |
bb42df46 CK |
940 | |
941 | if (dma_buf_is_dynamic(attach->dmabuf) && | |
4981cdb0 | 942 | !IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY)) |
bb42df46 | 943 | dma_buf_unpin(attach); |
d15bd7ee SS |
944 | } |
945 | EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment); | |
fc13020e | 946 | |
bb42df46 CK |
947 | /** |
948 | * dma_buf_move_notify - notify attachments that DMA-buf is moving | |
949 | * | |
950 | * @dmabuf: [in] buffer which is moving | |
951 | * | |
952 | * Informs all attachmenst that they need to destroy and recreated all their | |
953 | * mappings. | |
954 | */ | |
955 | void dma_buf_move_notify(struct dma_buf *dmabuf) | |
956 | { | |
957 | struct dma_buf_attachment *attach; | |
958 | ||
959 | dma_resv_assert_held(dmabuf->resv); | |
960 | ||
961 | list_for_each_entry(attach, &dmabuf->attachments, node) | |
4981cdb0 | 962 | if (attach->importer_ops) |
bb42df46 CK |
963 | attach->importer_ops->move_notify(attach); |
964 | } | |
965 | EXPORT_SYMBOL_GPL(dma_buf_move_notify); | |
966 | ||
0959a168 DV |
967 | /** |
968 | * DOC: cpu access | |
969 | * | |
970 | * There are mutliple reasons for supporting CPU access to a dma buffer object: | |
971 | * | |
972 | * - Fallback operations in the kernel, for example when a device is connected | |
973 | * over USB and the kernel needs to shuffle the data around first before | |
974 | * sending it away. Cache coherency is handled by braketing any transactions | |
975 | * with calls to dma_buf_begin_cpu_access() and dma_buf_end_cpu_access() | |
976 | * access. | |
977 | * | |
7f0de8d8 DV |
978 | * Since for most kernel internal dma-buf accesses need the entire buffer, a |
979 | * vmap interface is introduced. Note that on very old 32-bit architectures | |
980 | * vmalloc space might be limited and result in vmap calls failing. | |
0959a168 DV |
981 | * |
982 | * Interfaces:: | |
983 | * void \*dma_buf_vmap(struct dma_buf \*dmabuf) | |
984 | * void dma_buf_vunmap(struct dma_buf \*dmabuf, void \*vaddr) | |
985 | * | |
986 | * The vmap call can fail if there is no vmap support in the exporter, or if | |
987 | * it runs out of vmalloc space. Fallback to kmap should be implemented. Note | |
988 | * that the dma-buf layer keeps a reference count for all vmap access and | |
989 | * calls down into the exporter's vmap function only when no vmapping exists, | |
990 | * and only unmaps it once. Protection against concurrent vmap/vunmap calls is | |
991 | * provided by taking the dma_buf->lock mutex. | |
992 | * | |
993 | * - For full compatibility on the importer side with existing userspace | |
994 | * interfaces, which might already support mmap'ing buffers. This is needed in | |
995 | * many processing pipelines (e.g. feeding a software rendered image into a | |
996 | * hardware pipeline, thumbnail creation, snapshots, ...). Also, Android's ION | |
997 | * framework already supported this and for DMA buffer file descriptors to | |
998 | * replace ION buffers mmap support was needed. | |
999 | * | |
1000 | * There is no special interfaces, userspace simply calls mmap on the dma-buf | |
1001 | * fd. But like for CPU access there's a need to braket the actual access, | |
1002 | * which is handled by the ioctl (DMA_BUF_IOCTL_SYNC). Note that | |
1003 | * DMA_BUF_IOCTL_SYNC can fail with -EAGAIN or -EINTR, in which case it must | |
1004 | * be restarted. | |
1005 | * | |
1006 | * Some systems might need some sort of cache coherency management e.g. when | |
1007 | * CPU and GPU domains are being accessed through dma-buf at the same time. | |
1008 | * To circumvent this problem there are begin/end coherency markers, that | |
1009 | * forward directly to existing dma-buf device drivers vfunc hooks. Userspace | |
1010 | * can make use of those markers through the DMA_BUF_IOCTL_SYNC ioctl. The | |
1011 | * sequence would be used like following: | |
1012 | * | |
1013 | * - mmap dma-buf fd | |
1014 | * - for each drawing/upload cycle in CPU 1. SYNC_START ioctl, 2. read/write | |
1015 | * to mmap area 3. SYNC_END ioctl. This can be repeated as often as you | |
1016 | * want (with the new data being consumed by say the GPU or the scanout | |
1017 | * device) | |
1018 | * - munmap once you don't need the buffer any more | |
1019 | * | |
1020 | * For correctness and optimal performance, it is always required to use | |
1021 | * SYNC_START and SYNC_END before and after, respectively, when accessing the | |
1022 | * mapped address. Userspace cannot rely on coherent access, even when there | |
1023 | * are systems where it just works without calling these ioctls. | |
1024 | * | |
1025 | * - And as a CPU fallback in userspace processing pipelines. | |
1026 | * | |
1027 | * Similar to the motivation for kernel cpu access it is again important that | |
1028 | * the userspace code of a given importing subsystem can use the same | |
1029 | * interfaces with a imported dma-buf buffer object as with a native buffer | |
1030 | * object. This is especially important for drm where the userspace part of | |
1031 | * contemporary OpenGL, X, and other drivers is huge, and reworking them to | |
1032 | * use a different way to mmap a buffer rather invasive. | |
1033 | * | |
1034 | * The assumption in the current dma-buf interfaces is that redirecting the | |
1035 | * initial mmap is all that's needed. A survey of some of the existing | |
1036 | * subsystems shows that no driver seems to do any nefarious thing like | |
1037 | * syncing up with outstanding asynchronous processing on the device or | |
1038 | * allocating special resources at fault time. So hopefully this is good | |
1039 | * enough, since adding interfaces to intercept pagefaults and allow pte | |
1040 | * shootdowns would increase the complexity quite a bit. | |
1041 | * | |
1042 | * Interface:: | |
1043 | * int dma_buf_mmap(struct dma_buf \*, struct vm_area_struct \*, | |
1044 | * unsigned long); | |
1045 | * | |
1046 | * If the importing subsystem simply provides a special-purpose mmap call to | |
1047 | * set up a mapping in userspace, calling do_mmap with dma_buf->file will | |
1048 | * equally achieve that for a dma-buf object. | |
1049 | */ | |
1050 | ||
ae4e46b1 CW |
1051 | static int __dma_buf_begin_cpu_access(struct dma_buf *dmabuf, |
1052 | enum dma_data_direction direction) | |
1053 | { | |
1054 | bool write = (direction == DMA_BIDIRECTIONAL || | |
1055 | direction == DMA_TO_DEVICE); | |
52791eee | 1056 | struct dma_resv *resv = dmabuf->resv; |
ae4e46b1 CW |
1057 | long ret; |
1058 | ||
1059 | /* Wait on any implicit rendering fences */ | |
52791eee | 1060 | ret = dma_resv_wait_timeout_rcu(resv, write, true, |
ae4e46b1 CW |
1061 | MAX_SCHEDULE_TIMEOUT); |
1062 | if (ret < 0) | |
1063 | return ret; | |
1064 | ||
1065 | return 0; | |
1066 | } | |
fc13020e DV |
1067 | |
1068 | /** | |
1069 | * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the | |
1070 | * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific | |
1071 | * preparations. Coherency is only guaranteed in the specified range for the | |
1072 | * specified access direction. | |
efb4df82 | 1073 | * @dmabuf: [in] buffer to prepare cpu access for. |
fc13020e DV |
1074 | * @direction: [in] length of range for cpu access. |
1075 | * | |
0959a168 DV |
1076 | * After the cpu access is complete the caller should call |
1077 | * dma_buf_end_cpu_access(). Only when cpu access is braketed by both calls is | |
1078 | * it guaranteed to be coherent with other DMA access. | |
1079 | * | |
fc13020e DV |
1080 | * Can return negative error values, returns 0 on success. |
1081 | */ | |
831e9da7 | 1082 | int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, |
fc13020e DV |
1083 | enum dma_data_direction direction) |
1084 | { | |
1085 | int ret = 0; | |
1086 | ||
1087 | if (WARN_ON(!dmabuf)) | |
1088 | return -EINVAL; | |
1089 | ||
1090 | if (dmabuf->ops->begin_cpu_access) | |
831e9da7 | 1091 | ret = dmabuf->ops->begin_cpu_access(dmabuf, direction); |
fc13020e | 1092 | |
ae4e46b1 CW |
1093 | /* Ensure that all fences are waited upon - but we first allow |
1094 | * the native handler the chance to do so more efficiently if it | |
1095 | * chooses. A double invocation here will be reasonably cheap no-op. | |
1096 | */ | |
1097 | if (ret == 0) | |
1098 | ret = __dma_buf_begin_cpu_access(dmabuf, direction); | |
1099 | ||
fc13020e DV |
1100 | return ret; |
1101 | } | |
1102 | EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access); | |
1103 | ||
1104 | /** | |
1105 | * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the | |
1106 | * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific | |
1107 | * actions. Coherency is only guaranteed in the specified range for the | |
1108 | * specified access direction. | |
efb4df82 | 1109 | * @dmabuf: [in] buffer to complete cpu access for. |
fc13020e DV |
1110 | * @direction: [in] length of range for cpu access. |
1111 | * | |
0959a168 DV |
1112 | * This terminates CPU access started with dma_buf_begin_cpu_access(). |
1113 | * | |
87e332d5 | 1114 | * Can return negative error values, returns 0 on success. |
fc13020e | 1115 | */ |
18b862dc CW |
1116 | int dma_buf_end_cpu_access(struct dma_buf *dmabuf, |
1117 | enum dma_data_direction direction) | |
fc13020e | 1118 | { |
18b862dc CW |
1119 | int ret = 0; |
1120 | ||
fc13020e DV |
1121 | WARN_ON(!dmabuf); |
1122 | ||
1123 | if (dmabuf->ops->end_cpu_access) | |
18b862dc CW |
1124 | ret = dmabuf->ops->end_cpu_access(dmabuf, direction); |
1125 | ||
1126 | return ret; | |
fc13020e DV |
1127 | } |
1128 | EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access); | |
1129 | ||
4c78513e DV |
1130 | |
1131 | /** | |
1132 | * dma_buf_mmap - Setup up a userspace mmap with the given vma | |
12c4727e | 1133 | * @dmabuf: [in] buffer that should back the vma |
4c78513e DV |
1134 | * @vma: [in] vma for the mmap |
1135 | * @pgoff: [in] offset in pages where this mmap should start within the | |
5136629d | 1136 | * dma-buf buffer. |
4c78513e DV |
1137 | * |
1138 | * This function adjusts the passed in vma so that it points at the file of the | |
ecf1dbac | 1139 | * dma_buf operation. It also adjusts the starting pgoff and does bounds |
4c78513e DV |
1140 | * checking on the size of the vma. Then it calls the exporters mmap function to |
1141 | * set up the mapping. | |
1142 | * | |
1143 | * Can return negative error values, returns 0 on success. | |
1144 | */ | |
1145 | int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, | |
1146 | unsigned long pgoff) | |
1147 | { | |
495c10cc JS |
1148 | struct file *oldfile; |
1149 | int ret; | |
1150 | ||
4c78513e DV |
1151 | if (WARN_ON(!dmabuf || !vma)) |
1152 | return -EINVAL; | |
1153 | ||
e3a9d6c5 AD |
1154 | /* check if buffer supports mmap */ |
1155 | if (!dmabuf->ops->mmap) | |
1156 | return -EINVAL; | |
1157 | ||
4c78513e | 1158 | /* check for offset overflow */ |
b02da6f8 | 1159 | if (pgoff + vma_pages(vma) < pgoff) |
4c78513e DV |
1160 | return -EOVERFLOW; |
1161 | ||
1162 | /* check for overflowing the buffer's size */ | |
b02da6f8 | 1163 | if (pgoff + vma_pages(vma) > |
4c78513e DV |
1164 | dmabuf->size >> PAGE_SHIFT) |
1165 | return -EINVAL; | |
1166 | ||
1167 | /* readjust the vma */ | |
495c10cc JS |
1168 | get_file(dmabuf->file); |
1169 | oldfile = vma->vm_file; | |
1170 | vma->vm_file = dmabuf->file; | |
4c78513e DV |
1171 | vma->vm_pgoff = pgoff; |
1172 | ||
495c10cc JS |
1173 | ret = dmabuf->ops->mmap(dmabuf, vma); |
1174 | if (ret) { | |
1175 | /* restore old parameters on failure */ | |
1176 | vma->vm_file = oldfile; | |
1177 | fput(dmabuf->file); | |
1178 | } else { | |
1179 | if (oldfile) | |
1180 | fput(oldfile); | |
1181 | } | |
1182 | return ret; | |
1183 | ||
4c78513e DV |
1184 | } |
1185 | EXPORT_SYMBOL_GPL(dma_buf_mmap); | |
98f86c9e DA |
1186 | |
1187 | /** | |
12c4727e SS |
1188 | * dma_buf_vmap - Create virtual mapping for the buffer object into kernel |
1189 | * address space. Same restrictions as for vmap and friends apply. | |
1190 | * @dmabuf: [in] buffer to vmap | |
98f86c9e DA |
1191 | * |
1192 | * This call may fail due to lack of virtual mapping address space. | |
1193 | * These calls are optional in drivers. The intended use for them | |
1194 | * is for mapping objects linear in kernel space for high use objects. | |
1195 | * Please attempt to use kmap/kunmap before thinking about these interfaces. | |
fee0c54e CC |
1196 | * |
1197 | * Returns NULL on error. | |
98f86c9e DA |
1198 | */ |
1199 | void *dma_buf_vmap(struct dma_buf *dmabuf) | |
1200 | { | |
f00b4dad DV |
1201 | void *ptr; |
1202 | ||
98f86c9e DA |
1203 | if (WARN_ON(!dmabuf)) |
1204 | return NULL; | |
1205 | ||
f00b4dad DV |
1206 | if (!dmabuf->ops->vmap) |
1207 | return NULL; | |
1208 | ||
1209 | mutex_lock(&dmabuf->lock); | |
1210 | if (dmabuf->vmapping_counter) { | |
1211 | dmabuf->vmapping_counter++; | |
1212 | BUG_ON(!dmabuf->vmap_ptr); | |
1213 | ptr = dmabuf->vmap_ptr; | |
1214 | goto out_unlock; | |
1215 | } | |
1216 | ||
1217 | BUG_ON(dmabuf->vmap_ptr); | |
1218 | ||
1219 | ptr = dmabuf->ops->vmap(dmabuf); | |
fee0c54e CC |
1220 | if (WARN_ON_ONCE(IS_ERR(ptr))) |
1221 | ptr = NULL; | |
1222 | if (!ptr) | |
f00b4dad DV |
1223 | goto out_unlock; |
1224 | ||
1225 | dmabuf->vmap_ptr = ptr; | |
1226 | dmabuf->vmapping_counter = 1; | |
1227 | ||
1228 | out_unlock: | |
1229 | mutex_unlock(&dmabuf->lock); | |
1230 | return ptr; | |
98f86c9e DA |
1231 | } |
1232 | EXPORT_SYMBOL_GPL(dma_buf_vmap); | |
1233 | ||
1234 | /** | |
1235 | * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap. | |
12c4727e | 1236 | * @dmabuf: [in] buffer to vunmap |
6e7b4a59 | 1237 | * @vaddr: [in] vmap to vunmap |
98f86c9e DA |
1238 | */ |
1239 | void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr) | |
1240 | { | |
1241 | if (WARN_ON(!dmabuf)) | |
1242 | return; | |
1243 | ||
f00b4dad DV |
1244 | BUG_ON(!dmabuf->vmap_ptr); |
1245 | BUG_ON(dmabuf->vmapping_counter == 0); | |
1246 | BUG_ON(dmabuf->vmap_ptr != vaddr); | |
1247 | ||
1248 | mutex_lock(&dmabuf->lock); | |
1249 | if (--dmabuf->vmapping_counter == 0) { | |
1250 | if (dmabuf->ops->vunmap) | |
1251 | dmabuf->ops->vunmap(dmabuf, vaddr); | |
1252 | dmabuf->vmap_ptr = NULL; | |
1253 | } | |
1254 | mutex_unlock(&dmabuf->lock); | |
98f86c9e DA |
1255 | } |
1256 | EXPORT_SYMBOL_GPL(dma_buf_vunmap); | |
b89e3563 SS |
1257 | |
1258 | #ifdef CONFIG_DEBUG_FS | |
eb0b947e | 1259 | static int dma_buf_debug_show(struct seq_file *s, void *unused) |
b89e3563 SS |
1260 | { |
1261 | int ret; | |
1262 | struct dma_buf *buf_obj; | |
1263 | struct dma_buf_attachment *attach_obj; | |
52791eee CK |
1264 | struct dma_resv *robj; |
1265 | struct dma_resv_list *fobj; | |
5eb2c72c | 1266 | struct dma_fence *fence; |
b016cd6e | 1267 | unsigned seq; |
5eb2c72c | 1268 | int count = 0, attach_count, shared_count, i; |
b89e3563 SS |
1269 | size_t size = 0; |
1270 | ||
1271 | ret = mutex_lock_interruptible(&db_list.lock); | |
1272 | ||
1273 | if (ret) | |
1274 | return ret; | |
1275 | ||
c0b00a52 | 1276 | seq_puts(s, "\nDma-buf Objects:\n"); |
ed63bb1d GH |
1277 | seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\t%-8s\n", |
1278 | "size", "flags", "mode", "count", "ino"); | |
b89e3563 SS |
1279 | |
1280 | list_for_each_entry(buf_obj, &db_list.head, list_node) { | |
15fd552d | 1281 | |
15fd552d CK |
1282 | ret = dma_resv_lock_interruptible(buf_obj->resv, NULL); |
1283 | if (ret) | |
f45f57cc | 1284 | goto error_unlock; |
b89e3563 | 1285 | |
bb2bb903 | 1286 | seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\n", |
c0b00a52 | 1287 | buf_obj->size, |
b89e3563 | 1288 | buf_obj->file->f_flags, buf_obj->file->f_mode, |
a1f6dbac | 1289 | file_count(buf_obj->file), |
ed63bb1d | 1290 | buf_obj->exp_name, |
bb2bb903 GH |
1291 | file_inode(buf_obj->file)->i_ino, |
1292 | buf_obj->name ?: ""); | |
b89e3563 | 1293 | |
5eb2c72c | 1294 | robj = buf_obj->resv; |
b016cd6e CW |
1295 | while (true) { |
1296 | seq = read_seqcount_begin(&robj->seq); | |
1297 | rcu_read_lock(); | |
1298 | fobj = rcu_dereference(robj->fence); | |
1299 | shared_count = fobj ? fobj->shared_count : 0; | |
1300 | fence = rcu_dereference(robj->fence_excl); | |
1301 | if (!read_seqcount_retry(&robj->seq, seq)) | |
1302 | break; | |
1303 | rcu_read_unlock(); | |
1304 | } | |
5eb2c72c RK |
1305 | |
1306 | if (fence) | |
1307 | seq_printf(s, "\tExclusive fence: %s %s %ssignalled\n", | |
1308 | fence->ops->get_driver_name(fence), | |
1309 | fence->ops->get_timeline_name(fence), | |
1310 | dma_fence_is_signaled(fence) ? "" : "un"); | |
1311 | for (i = 0; i < shared_count; i++) { | |
1312 | fence = rcu_dereference(fobj->shared[i]); | |
1313 | if (!dma_fence_get_rcu(fence)) | |
1314 | continue; | |
1315 | seq_printf(s, "\tShared fence: %s %s %ssignalled\n", | |
1316 | fence->ops->get_driver_name(fence), | |
1317 | fence->ops->get_timeline_name(fence), | |
1318 | dma_fence_is_signaled(fence) ? "" : "un"); | |
5e383a97 | 1319 | dma_fence_put(fence); |
5eb2c72c RK |
1320 | } |
1321 | rcu_read_unlock(); | |
1322 | ||
c0b00a52 | 1323 | seq_puts(s, "\tAttached Devices:\n"); |
b89e3563 SS |
1324 | attach_count = 0; |
1325 | ||
1326 | list_for_each_entry(attach_obj, &buf_obj->attachments, node) { | |
9eddb41d | 1327 | seq_printf(s, "\t%s\n", dev_name(attach_obj->dev)); |
b89e3563 SS |
1328 | attach_count++; |
1329 | } | |
15fd552d | 1330 | dma_resv_unlock(buf_obj->resv); |
b89e3563 | 1331 | |
c0b00a52 | 1332 | seq_printf(s, "Total %d devices attached\n\n", |
b89e3563 SS |
1333 | attach_count); |
1334 | ||
1335 | count++; | |
1336 | size += buf_obj->size; | |
b89e3563 SS |
1337 | } |
1338 | ||
1339 | seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size); | |
1340 | ||
1341 | mutex_unlock(&db_list.lock); | |
1342 | return 0; | |
15fd552d | 1343 | |
f45f57cc | 1344 | error_unlock: |
15fd552d CK |
1345 | mutex_unlock(&db_list.lock); |
1346 | return ret; | |
b89e3563 SS |
1347 | } |
1348 | ||
2674305a | 1349 | DEFINE_SHOW_ATTRIBUTE(dma_buf_debug); |
b89e3563 SS |
1350 | |
1351 | static struct dentry *dma_buf_debugfs_dir; | |
1352 | ||
1353 | static int dma_buf_init_debugfs(void) | |
1354 | { | |
bd3e2208 | 1355 | struct dentry *d; |
b89e3563 | 1356 | int err = 0; |
5136629d | 1357 | |
bd3e2208 MK |
1358 | d = debugfs_create_dir("dma_buf", NULL); |
1359 | if (IS_ERR(d)) | |
1360 | return PTR_ERR(d); | |
5136629d | 1361 | |
bd3e2208 | 1362 | dma_buf_debugfs_dir = d; |
b89e3563 | 1363 | |
bd3e2208 MK |
1364 | d = debugfs_create_file("bufinfo", S_IRUGO, dma_buf_debugfs_dir, |
1365 | NULL, &dma_buf_debug_fops); | |
1366 | if (IS_ERR(d)) { | |
b89e3563 | 1367 | pr_debug("dma_buf: debugfs: failed to create node bufinfo\n"); |
b7479990 MK |
1368 | debugfs_remove_recursive(dma_buf_debugfs_dir); |
1369 | dma_buf_debugfs_dir = NULL; | |
bd3e2208 | 1370 | err = PTR_ERR(d); |
b7479990 | 1371 | } |
b89e3563 SS |
1372 | |
1373 | return err; | |
1374 | } | |
1375 | ||
1376 | static void dma_buf_uninit_debugfs(void) | |
1377 | { | |
298b6a81 | 1378 | debugfs_remove_recursive(dma_buf_debugfs_dir); |
b89e3563 | 1379 | } |
b89e3563 SS |
1380 | #else |
1381 | static inline int dma_buf_init_debugfs(void) | |
1382 | { | |
1383 | return 0; | |
1384 | } | |
1385 | static inline void dma_buf_uninit_debugfs(void) | |
1386 | { | |
1387 | } | |
1388 | #endif | |
1389 | ||
1390 | static int __init dma_buf_init(void) | |
1391 | { | |
ed63bb1d GH |
1392 | dma_buf_mnt = kern_mount(&dma_buf_fs_type); |
1393 | if (IS_ERR(dma_buf_mnt)) | |
1394 | return PTR_ERR(dma_buf_mnt); | |
1395 | ||
b89e3563 SS |
1396 | mutex_init(&db_list.lock); |
1397 | INIT_LIST_HEAD(&db_list.head); | |
1398 | dma_buf_init_debugfs(); | |
1399 | return 0; | |
1400 | } | |
1401 | subsys_initcall(dma_buf_init); | |
1402 | ||
1403 | static void __exit dma_buf_deinit(void) | |
1404 | { | |
1405 | dma_buf_uninit_debugfs(); | |
ed63bb1d | 1406 | kern_unmount(dma_buf_mnt); |
b89e3563 SS |
1407 | } |
1408 | __exitcall(dma_buf_deinit); |