1 // SPDX-License-Identifier: GPL-2.0-only
3 * Framework for buffer objects that can be shared across devices/subsystems.
5 * Copyright(C) 2011 Linaro Limited. All rights reserved.
6 * Author: Sumit Semwal <sumit.semwal@ti.com>
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.
15 #include <linux/slab.h>
16 #include <linux/dma-buf.h>
17 #include <linux/dma-fence.h>
18 #include <linux/dma-fence-unwrap.h>
19 #include <linux/anon_inodes.h>
20 #include <linux/export.h>
21 #include <linux/debugfs.h>
22 #include <linux/module.h>
23 #include <linux/seq_file.h>
24 #include <linux/sync_file.h>
25 #include <linux/poll.h>
26 #include <linux/dma-resv.h>
28 #include <linux/mount.h>
29 #include <linux/pseudo_fs.h>
31 #include <uapi/linux/dma-buf.h>
32 #include <uapi/linux/magic.h>
34 #include "dma-buf-sysfs-stats.h"
36 static inline int is_dma_buf_file(struct file *);
39 struct list_head head;
43 static struct dma_buf_list db_list;
45 static char *dmabuffs_dname(struct dentry *dentry, char *buffer, int buflen)
47 struct dma_buf *dmabuf;
48 char name[DMA_BUF_NAME_LEN];
51 dmabuf = dentry->d_fsdata;
52 spin_lock(&dmabuf->name_lock);
54 ret = strlcpy(name, dmabuf->name, DMA_BUF_NAME_LEN);
55 spin_unlock(&dmabuf->name_lock);
57 return dynamic_dname(buffer, buflen, "/%s:%s",
58 dentry->d_name.name, ret > 0 ? name : "");
61 static void dma_buf_release(struct dentry *dentry)
63 struct dma_buf *dmabuf;
65 dmabuf = dentry->d_fsdata;
66 if (unlikely(!dmabuf))
69 BUG_ON(dmabuf->vmapping_counter);
72 * If you hit this BUG() it could mean:
73 * * There's a file reference imbalance in dma_buf_poll / dma_buf_poll_cb or somewhere else
74 * * dmabuf->cb_in/out.active are non-0 despite no pending fence callback
76 BUG_ON(dmabuf->cb_in.active || dmabuf->cb_out.active);
78 dma_buf_stats_teardown(dmabuf);
79 dmabuf->ops->release(dmabuf);
81 if (dmabuf->resv == (struct dma_resv *)&dmabuf[1])
82 dma_resv_fini(dmabuf->resv);
84 WARN_ON(!list_empty(&dmabuf->attachments));
85 module_put(dmabuf->owner);
90 static int dma_buf_file_release(struct inode *inode, struct file *file)
92 struct dma_buf *dmabuf;
94 if (!is_dma_buf_file(file))
97 dmabuf = file->private_data;
99 mutex_lock(&db_list.lock);
100 list_del(&dmabuf->list_node);
101 mutex_unlock(&db_list.lock);
106 static const struct dentry_operations dma_buf_dentry_ops = {
107 .d_dname = dmabuffs_dname,
108 .d_release = dma_buf_release,
111 static struct vfsmount *dma_buf_mnt;
113 static int dma_buf_fs_init_context(struct fs_context *fc)
115 struct pseudo_fs_context *ctx;
117 ctx = init_pseudo(fc, DMA_BUF_MAGIC);
120 ctx->dops = &dma_buf_dentry_ops;
124 static struct file_system_type dma_buf_fs_type = {
126 .init_fs_context = dma_buf_fs_init_context,
127 .kill_sb = kill_anon_super,
130 static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
132 struct dma_buf *dmabuf;
135 if (!is_dma_buf_file(file))
138 dmabuf = file->private_data;
140 /* check if buffer supports mmap */
141 if (!dmabuf->ops->mmap)
144 /* check for overflowing the buffer's size */
145 if (vma->vm_pgoff + vma_pages(vma) >
146 dmabuf->size >> PAGE_SHIFT)
149 dma_resv_lock(dmabuf->resv, NULL);
150 ret = dmabuf->ops->mmap(dmabuf, vma);
151 dma_resv_unlock(dmabuf->resv);
156 static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
158 struct dma_buf *dmabuf;
161 if (!is_dma_buf_file(file))
164 dmabuf = file->private_data;
166 /* only support discovering the end of the buffer,
167 but also allow SEEK_SET to maintain the idiomatic
168 SEEK_END(0), SEEK_CUR(0) pattern */
169 if (whence == SEEK_END)
171 else if (whence == SEEK_SET)
179 return base + offset;
183 * DOC: implicit fence polling
185 * To support cross-device and cross-driver synchronization of buffer access
186 * implicit fences (represented internally in the kernel with &struct dma_fence)
187 * can be attached to a &dma_buf. The glue for that and a few related things are
188 * provided in the &dma_resv structure.
190 * Userspace can query the state of these implicitly tracked fences using poll()
191 * and related system calls:
193 * - Checking for EPOLLIN, i.e. read access, can be use to query the state of the
194 * most recent write or exclusive fence.
196 * - Checking for EPOLLOUT, i.e. write access, can be used to query the state of
197 * all attached fences, shared and exclusive ones.
199 * Note that this only signals the completion of the respective fences, i.e. the
200 * DMA transfers are complete. Cache flushing and any other necessary
201 * preparations before CPU access can begin still need to happen.
203 * As an alternative to poll(), the set of fences on DMA buffer can be
204 * exported as a &sync_file using &dma_buf_sync_file_export.
207 static void dma_buf_poll_cb(struct dma_fence *fence, struct dma_fence_cb *cb)
209 struct dma_buf_poll_cb_t *dcb = (struct dma_buf_poll_cb_t *)cb;
210 struct dma_buf *dmabuf = container_of(dcb->poll, struct dma_buf, poll);
213 spin_lock_irqsave(&dcb->poll->lock, flags);
214 wake_up_locked_poll(dcb->poll, dcb->active);
216 spin_unlock_irqrestore(&dcb->poll->lock, flags);
217 dma_fence_put(fence);
218 /* Paired with get_file in dma_buf_poll */
222 static bool dma_buf_poll_add_cb(struct dma_resv *resv, bool write,
223 struct dma_buf_poll_cb_t *dcb)
225 struct dma_resv_iter cursor;
226 struct dma_fence *fence;
229 dma_resv_for_each_fence(&cursor, resv, dma_resv_usage_rw(write),
231 dma_fence_get(fence);
232 r = dma_fence_add_callback(fence, &dcb->cb, dma_buf_poll_cb);
235 dma_fence_put(fence);
241 static __poll_t dma_buf_poll(struct file *file, poll_table *poll)
243 struct dma_buf *dmabuf;
244 struct dma_resv *resv;
247 dmabuf = file->private_data;
248 if (!dmabuf || !dmabuf->resv)
253 poll_wait(file, &dmabuf->poll, poll);
255 events = poll_requested_events(poll) & (EPOLLIN | EPOLLOUT);
259 dma_resv_lock(resv, NULL);
261 if (events & EPOLLOUT) {
262 struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_out;
264 /* Check that callback isn't busy */
265 spin_lock_irq(&dmabuf->poll.lock);
269 dcb->active = EPOLLOUT;
270 spin_unlock_irq(&dmabuf->poll.lock);
272 if (events & EPOLLOUT) {
273 /* Paired with fput in dma_buf_poll_cb */
274 get_file(dmabuf->file);
276 if (!dma_buf_poll_add_cb(resv, true, dcb))
277 /* No callback queued, wake up any other waiters */
278 dma_buf_poll_cb(NULL, &dcb->cb);
284 if (events & EPOLLIN) {
285 struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_in;
287 /* Check that callback isn't busy */
288 spin_lock_irq(&dmabuf->poll.lock);
292 dcb->active = EPOLLIN;
293 spin_unlock_irq(&dmabuf->poll.lock);
295 if (events & EPOLLIN) {
296 /* Paired with fput in dma_buf_poll_cb */
297 get_file(dmabuf->file);
299 if (!dma_buf_poll_add_cb(resv, false, dcb))
300 /* No callback queued, wake up any other waiters */
301 dma_buf_poll_cb(NULL, &dcb->cb);
307 dma_resv_unlock(resv);
312 * dma_buf_set_name - Set a name to a specific dma_buf to track the usage.
313 * It could support changing the name of the dma-buf if the same
314 * piece of memory is used for multiple purpose between different devices.
316 * @dmabuf: [in] dmabuf buffer that will be renamed.
317 * @buf: [in] A piece of userspace memory that contains the name of
320 * Returns 0 on success. If the dma-buf buffer is already attached to
321 * devices, return -EBUSY.
324 static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf)
326 char *name = strndup_user(buf, DMA_BUF_NAME_LEN);
329 return PTR_ERR(name);
331 spin_lock(&dmabuf->name_lock);
334 spin_unlock(&dmabuf->name_lock);
339 #if IS_ENABLED(CONFIG_SYNC_FILE)
340 static long dma_buf_export_sync_file(struct dma_buf *dmabuf,
341 void __user *user_data)
343 struct dma_buf_export_sync_file arg;
344 enum dma_resv_usage usage;
345 struct dma_fence *fence = NULL;
346 struct sync_file *sync_file;
349 if (copy_from_user(&arg, user_data, sizeof(arg)))
352 if (arg.flags & ~DMA_BUF_SYNC_RW)
355 if ((arg.flags & DMA_BUF_SYNC_RW) == 0)
358 fd = get_unused_fd_flags(O_CLOEXEC);
362 usage = dma_resv_usage_rw(arg.flags & DMA_BUF_SYNC_WRITE);
363 ret = dma_resv_get_singleton(dmabuf->resv, usage, &fence);
368 fence = dma_fence_get_stub();
370 sync_file = sync_file_create(fence);
372 dma_fence_put(fence);
380 if (copy_to_user(user_data, &arg, sizeof(arg))) {
385 fd_install(fd, sync_file->file);
390 fput(sync_file->file);
396 static long dma_buf_import_sync_file(struct dma_buf *dmabuf,
397 const void __user *user_data)
399 struct dma_buf_import_sync_file arg;
400 struct dma_fence *fence, *f;
401 enum dma_resv_usage usage;
402 struct dma_fence_unwrap iter;
403 unsigned int num_fences;
406 if (copy_from_user(&arg, user_data, sizeof(arg)))
409 if (arg.flags & ~DMA_BUF_SYNC_RW)
412 if ((arg.flags & DMA_BUF_SYNC_RW) == 0)
415 fence = sync_file_get_fence(arg.fd);
419 usage = (arg.flags & DMA_BUF_SYNC_WRITE) ? DMA_RESV_USAGE_WRITE :
423 dma_fence_unwrap_for_each(f, &iter, fence)
426 if (num_fences > 0) {
427 dma_resv_lock(dmabuf->resv, NULL);
429 ret = dma_resv_reserve_fences(dmabuf->resv, num_fences);
431 dma_fence_unwrap_for_each(f, &iter, fence)
432 dma_resv_add_fence(dmabuf->resv, f, usage);
435 dma_resv_unlock(dmabuf->resv);
438 dma_fence_put(fence);
444 static long dma_buf_ioctl(struct file *file,
445 unsigned int cmd, unsigned long arg)
447 struct dma_buf *dmabuf;
448 struct dma_buf_sync sync;
449 enum dma_data_direction direction;
452 dmabuf = file->private_data;
455 case DMA_BUF_IOCTL_SYNC:
456 if (copy_from_user(&sync, (void __user *) arg, sizeof(sync)))
459 if (sync.flags & ~DMA_BUF_SYNC_VALID_FLAGS_MASK)
462 switch (sync.flags & DMA_BUF_SYNC_RW) {
463 case DMA_BUF_SYNC_READ:
464 direction = DMA_FROM_DEVICE;
466 case DMA_BUF_SYNC_WRITE:
467 direction = DMA_TO_DEVICE;
469 case DMA_BUF_SYNC_RW:
470 direction = DMA_BIDIRECTIONAL;
476 if (sync.flags & DMA_BUF_SYNC_END)
477 ret = dma_buf_end_cpu_access(dmabuf, direction);
479 ret = dma_buf_begin_cpu_access(dmabuf, direction);
483 case DMA_BUF_SET_NAME_A:
484 case DMA_BUF_SET_NAME_B:
485 return dma_buf_set_name(dmabuf, (const char __user *)arg);
487 #if IS_ENABLED(CONFIG_SYNC_FILE)
488 case DMA_BUF_IOCTL_EXPORT_SYNC_FILE:
489 return dma_buf_export_sync_file(dmabuf, (void __user *)arg);
490 case DMA_BUF_IOCTL_IMPORT_SYNC_FILE:
491 return dma_buf_import_sync_file(dmabuf, (const void __user *)arg);
499 static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file)
501 struct dma_buf *dmabuf = file->private_data;
503 seq_printf(m, "size:\t%zu\n", dmabuf->size);
504 /* Don't count the temporary reference taken inside procfs seq_show */
505 seq_printf(m, "count:\t%ld\n", file_count(dmabuf->file) - 1);
506 seq_printf(m, "exp_name:\t%s\n", dmabuf->exp_name);
507 spin_lock(&dmabuf->name_lock);
509 seq_printf(m, "name:\t%s\n", dmabuf->name);
510 spin_unlock(&dmabuf->name_lock);
513 static const struct file_operations dma_buf_fops = {
514 .release = dma_buf_file_release,
515 .mmap = dma_buf_mmap_internal,
516 .llseek = dma_buf_llseek,
517 .poll = dma_buf_poll,
518 .unlocked_ioctl = dma_buf_ioctl,
519 .compat_ioctl = compat_ptr_ioctl,
520 .show_fdinfo = dma_buf_show_fdinfo,
524 * is_dma_buf_file - Check if struct file* is associated with dma_buf
526 static inline int is_dma_buf_file(struct file *file)
528 return file->f_op == &dma_buf_fops;
531 static struct file *dma_buf_getfile(struct dma_buf *dmabuf, int flags)
533 static atomic64_t dmabuf_inode = ATOMIC64_INIT(0);
535 struct inode *inode = alloc_anon_inode(dma_buf_mnt->mnt_sb);
538 return ERR_CAST(inode);
540 inode->i_size = dmabuf->size;
541 inode_set_bytes(inode, dmabuf->size);
544 * The ->i_ino acquired from get_next_ino() is not unique thus
545 * not suitable for using it as dentry name by dmabuf stats.
546 * Override ->i_ino with the unique and dmabuffs specific
549 inode->i_ino = atomic64_add_return(1, &dmabuf_inode);
550 flags &= O_ACCMODE | O_NONBLOCK;
551 file = alloc_file_pseudo(inode, dma_buf_mnt, "dmabuf",
552 flags, &dma_buf_fops);
555 file->private_data = dmabuf;
556 file->f_path.dentry->d_fsdata = dmabuf;
566 * DOC: dma buf device access
568 * For device DMA access to a shared DMA buffer the usual sequence of operations
571 * 1. The exporter defines his exporter instance using
572 * DEFINE_DMA_BUF_EXPORT_INFO() and calls dma_buf_export() to wrap a private
573 * buffer object into a &dma_buf. It then exports that &dma_buf to userspace
574 * as a file descriptor by calling dma_buf_fd().
576 * 2. Userspace passes this file-descriptors to all drivers it wants this buffer
577 * to share with: First the file descriptor is converted to a &dma_buf using
578 * dma_buf_get(). Then the buffer is attached to the device using
581 * Up to this stage the exporter is still free to migrate or reallocate the
584 * 3. Once the buffer is attached to all devices userspace can initiate DMA
585 * access to the shared buffer. In the kernel this is done by calling
586 * dma_buf_map_attachment() and dma_buf_unmap_attachment().
588 * 4. Once a driver is done with a shared buffer it needs to call
589 * dma_buf_detach() (after cleaning up any mappings) and then release the
590 * reference acquired with dma_buf_get() by calling dma_buf_put().
592 * For the detailed semantics exporters are expected to implement see
597 * dma_buf_export - Creates a new dma_buf, and associates an anon file
598 * with this buffer, so it can be exported.
599 * Also connect the allocator specific data and ops to the buffer.
600 * Additionally, provide a name string for exporter; useful in debugging.
602 * @exp_info: [in] holds all the export related information provided
603 * by the exporter. see &struct dma_buf_export_info
604 * for further details.
606 * Returns, on success, a newly created struct dma_buf object, which wraps the
607 * supplied private data and operations for struct dma_buf_ops. On either
608 * missing ops, or error in allocating struct dma_buf, will return negative
611 * For most cases the easiest way to create @exp_info is through the
612 * %DEFINE_DMA_BUF_EXPORT_INFO macro.
614 struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
616 struct dma_buf *dmabuf;
617 struct dma_resv *resv = exp_info->resv;
619 size_t alloc_size = sizeof(struct dma_buf);
623 alloc_size += sizeof(struct dma_resv);
625 /* prevent &dma_buf[1] == dma_buf->resv */
628 if (WARN_ON(!exp_info->priv
630 || !exp_info->ops->map_dma_buf
631 || !exp_info->ops->unmap_dma_buf
632 || !exp_info->ops->release)) {
633 return ERR_PTR(-EINVAL);
636 if (WARN_ON(exp_info->ops->cache_sgt_mapping &&
637 (exp_info->ops->pin || exp_info->ops->unpin)))
638 return ERR_PTR(-EINVAL);
640 if (WARN_ON(!exp_info->ops->pin != !exp_info->ops->unpin))
641 return ERR_PTR(-EINVAL);
643 if (!try_module_get(exp_info->owner))
644 return ERR_PTR(-ENOENT);
646 dmabuf = kzalloc(alloc_size, GFP_KERNEL);
652 dmabuf->priv = exp_info->priv;
653 dmabuf->ops = exp_info->ops;
654 dmabuf->size = exp_info->size;
655 dmabuf->exp_name = exp_info->exp_name;
656 dmabuf->owner = exp_info->owner;
657 spin_lock_init(&dmabuf->name_lock);
658 init_waitqueue_head(&dmabuf->poll);
659 dmabuf->cb_in.poll = dmabuf->cb_out.poll = &dmabuf->poll;
660 dmabuf->cb_in.active = dmabuf->cb_out.active = 0;
663 resv = (struct dma_resv *)&dmabuf[1];
668 file = dma_buf_getfile(dmabuf, exp_info->flags);
676 INIT_LIST_HEAD(&dmabuf->attachments);
678 mutex_lock(&db_list.lock);
679 list_add(&dmabuf->list_node, &db_list.head);
680 mutex_unlock(&db_list.lock);
682 ret = dma_buf_stats_setup(dmabuf);
690 * Set file->f_path.dentry->d_fsdata to NULL so that when
691 * dma_buf_release() gets invoked by dentry_ops, it exits
692 * early before calling the release() dma_buf op.
694 file->f_path.dentry->d_fsdata = NULL;
699 module_put(exp_info->owner);
702 EXPORT_SYMBOL_NS_GPL(dma_buf_export, DMA_BUF);
705 * dma_buf_fd - returns a file descriptor for the given struct dma_buf
706 * @dmabuf: [in] pointer to dma_buf for which fd is required.
707 * @flags: [in] flags to give to fd
709 * On success, returns an associated 'fd'. Else, returns error.
711 int dma_buf_fd(struct dma_buf *dmabuf, int flags)
715 if (!dmabuf || !dmabuf->file)
718 fd = get_unused_fd_flags(flags);
722 fd_install(fd, dmabuf->file);
726 EXPORT_SYMBOL_NS_GPL(dma_buf_fd, DMA_BUF);
729 * dma_buf_get - returns the struct dma_buf related to an fd
730 * @fd: [in] fd associated with the struct dma_buf to be returned
732 * On success, returns the struct dma_buf associated with an fd; uses
733 * file's refcounting done by fget to increase refcount. returns ERR_PTR
736 struct dma_buf *dma_buf_get(int fd)
743 return ERR_PTR(-EBADF);
745 if (!is_dma_buf_file(file)) {
747 return ERR_PTR(-EINVAL);
750 return file->private_data;
752 EXPORT_SYMBOL_NS_GPL(dma_buf_get, DMA_BUF);
755 * dma_buf_put - decreases refcount of the buffer
756 * @dmabuf: [in] buffer to reduce refcount of
758 * Uses file's refcounting done implicitly by fput().
760 * If, as a result of this call, the refcount becomes 0, the 'release' file
761 * operation related to this fd is called. It calls &dma_buf_ops.release vfunc
762 * in turn, and frees the memory allocated for dmabuf when exported.
764 void dma_buf_put(struct dma_buf *dmabuf)
766 if (WARN_ON(!dmabuf || !dmabuf->file))
771 EXPORT_SYMBOL_NS_GPL(dma_buf_put, DMA_BUF);
773 static void mangle_sg_table(struct sg_table *sg_table)
775 #ifdef CONFIG_DMABUF_DEBUG
777 struct scatterlist *sg;
779 /* To catch abuse of the underlying struct page by importers mix
780 * up the bits, but take care to preserve the low SG_ bits to
781 * not corrupt the sgt. The mixing is undone in __unmap_dma_buf
782 * before passing the sgt back to the exporter. */
783 for_each_sgtable_sg(sg_table, sg, i)
784 sg->page_link ^= ~0xffUL;
788 static struct sg_table * __map_dma_buf(struct dma_buf_attachment *attach,
789 enum dma_data_direction direction)
791 struct sg_table *sg_table;
794 sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
795 if (IS_ERR_OR_NULL(sg_table))
798 if (!dma_buf_attachment_is_dynamic(attach)) {
799 ret = dma_resv_wait_timeout(attach->dmabuf->resv,
800 DMA_RESV_USAGE_KERNEL, true,
801 MAX_SCHEDULE_TIMEOUT);
803 attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
809 mangle_sg_table(sg_table);
814 * DOC: locking convention
816 * In order to avoid deadlock situations between dma-buf exports and importers,
817 * all dma-buf API users must follow the common dma-buf locking convention.
819 * Convention for importers
821 * 1. Importers must hold the dma-buf reservation lock when calling these
826 * - dma_buf_map_attachment()
827 * - dma_buf_unmap_attachment()
831 * 2. Importers must not hold the dma-buf reservation lock when calling these
835 * - dma_buf_dynamic_attach()
842 * - dma_buf_begin_cpu_access()
843 * - dma_buf_end_cpu_access()
844 * - dma_buf_map_attachment_unlocked()
845 * - dma_buf_unmap_attachment_unlocked()
846 * - dma_buf_vmap_unlocked()
847 * - dma_buf_vunmap_unlocked()
849 * Convention for exporters
851 * 1. These &dma_buf_ops callbacks are invoked with unlocked dma-buf
852 * reservation and exporter can take the lock:
854 * - &dma_buf_ops.attach()
855 * - &dma_buf_ops.detach()
856 * - &dma_buf_ops.release()
857 * - &dma_buf_ops.begin_cpu_access()
858 * - &dma_buf_ops.end_cpu_access()
860 * 2. These &dma_buf_ops callbacks are invoked with locked dma-buf
861 * reservation and exporter can't take the lock:
863 * - &dma_buf_ops.pin()
864 * - &dma_buf_ops.unpin()
865 * - &dma_buf_ops.map_dma_buf()
866 * - &dma_buf_ops.unmap_dma_buf()
867 * - &dma_buf_ops.mmap()
868 * - &dma_buf_ops.vmap()
869 * - &dma_buf_ops.vunmap()
871 * 3. Exporters must hold the dma-buf reservation lock when calling these
874 * - dma_buf_move_notify()
878 * dma_buf_dynamic_attach - Add the device to dma_buf's attachments list
879 * @dmabuf: [in] buffer to attach device to.
880 * @dev: [in] device to be attached.
881 * @importer_ops: [in] importer operations for the attachment
882 * @importer_priv: [in] importer private pointer for the attachment
884 * Returns struct dma_buf_attachment pointer for this attachment. Attachments
885 * must be cleaned up by calling dma_buf_detach().
887 * Optionally this calls &dma_buf_ops.attach to allow device-specific attach
892 * A pointer to newly created &dma_buf_attachment on success, or a negative
893 * error code wrapped into a pointer on failure.
895 * Note that this can fail if the backing storage of @dmabuf is in a place not
896 * accessible to @dev, and cannot be moved to a more suitable place. This is
897 * indicated with the error code -EBUSY.
899 struct dma_buf_attachment *
900 dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
901 const struct dma_buf_attach_ops *importer_ops,
904 struct dma_buf_attachment *attach;
907 if (WARN_ON(!dmabuf || !dev))
908 return ERR_PTR(-EINVAL);
910 if (WARN_ON(importer_ops && !importer_ops->move_notify))
911 return ERR_PTR(-EINVAL);
913 attach = kzalloc(sizeof(*attach), GFP_KERNEL);
915 return ERR_PTR(-ENOMEM);
918 attach->dmabuf = dmabuf;
920 attach->peer2peer = importer_ops->allow_peer2peer;
921 attach->importer_ops = importer_ops;
922 attach->importer_priv = importer_priv;
924 if (dmabuf->ops->attach) {
925 ret = dmabuf->ops->attach(dmabuf, attach);
929 dma_resv_lock(dmabuf->resv, NULL);
930 list_add(&attach->node, &dmabuf->attachments);
931 dma_resv_unlock(dmabuf->resv);
933 /* When either the importer or the exporter can't handle dynamic
934 * mappings we cache the mapping here to avoid issues with the
935 * reservation object lock.
937 if (dma_buf_attachment_is_dynamic(attach) !=
938 dma_buf_is_dynamic(dmabuf)) {
939 struct sg_table *sgt;
941 dma_resv_lock(attach->dmabuf->resv, NULL);
942 if (dma_buf_is_dynamic(attach->dmabuf)) {
943 ret = dmabuf->ops->pin(attach);
948 sgt = __map_dma_buf(attach, DMA_BIDIRECTIONAL);
950 sgt = ERR_PTR(-ENOMEM);
955 dma_resv_unlock(attach->dmabuf->resv);
957 attach->dir = DMA_BIDIRECTIONAL;
967 if (dma_buf_is_dynamic(attach->dmabuf))
968 dmabuf->ops->unpin(attach);
971 dma_resv_unlock(attach->dmabuf->resv);
973 dma_buf_detach(dmabuf, attach);
976 EXPORT_SYMBOL_NS_GPL(dma_buf_dynamic_attach, DMA_BUF);
979 * dma_buf_attach - Wrapper for dma_buf_dynamic_attach
980 * @dmabuf: [in] buffer to attach device to.
981 * @dev: [in] device to be attached.
983 * Wrapper to call dma_buf_dynamic_attach() for drivers which still use a static
986 struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
989 return dma_buf_dynamic_attach(dmabuf, dev, NULL, NULL);
991 EXPORT_SYMBOL_NS_GPL(dma_buf_attach, DMA_BUF);
993 static void __unmap_dma_buf(struct dma_buf_attachment *attach,
994 struct sg_table *sg_table,
995 enum dma_data_direction direction)
997 /* uses XOR, hence this unmangles */
998 mangle_sg_table(sg_table);
1000 attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction);
1004 * dma_buf_detach - Remove the given attachment from dmabuf's attachments list
1005 * @dmabuf: [in] buffer to detach from.
1006 * @attach: [in] attachment to be detached; is free'd after this call.
1008 * Clean up a device attachment obtained by calling dma_buf_attach().
1010 * Optionally this calls &dma_buf_ops.detach for device-specific detach.
1012 void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
1014 if (WARN_ON(!dmabuf || !attach || dmabuf != attach->dmabuf))
1017 dma_resv_lock(dmabuf->resv, NULL);
1021 __unmap_dma_buf(attach, attach->sgt, attach->dir);
1023 if (dma_buf_is_dynamic(attach->dmabuf))
1024 dmabuf->ops->unpin(attach);
1026 list_del(&attach->node);
1028 dma_resv_unlock(dmabuf->resv);
1030 if (dmabuf->ops->detach)
1031 dmabuf->ops->detach(dmabuf, attach);
1035 EXPORT_SYMBOL_NS_GPL(dma_buf_detach, DMA_BUF);
1038 * dma_buf_pin - Lock down the DMA-buf
1039 * @attach: [in] attachment which should be pinned
1041 * Only dynamic importers (who set up @attach with dma_buf_dynamic_attach()) may
1042 * call this, and only for limited use cases like scanout and not for temporary
1043 * pin operations. It is not permitted to allow userspace to pin arbitrary
1044 * amounts of buffers through this interface.
1046 * Buffers must be unpinned by calling dma_buf_unpin().
1049 * 0 on success, negative error code on failure.
1051 int dma_buf_pin(struct dma_buf_attachment *attach)
1053 struct dma_buf *dmabuf = attach->dmabuf;
1056 WARN_ON(!dma_buf_attachment_is_dynamic(attach));
1058 dma_resv_assert_held(dmabuf->resv);
1060 if (dmabuf->ops->pin)
1061 ret = dmabuf->ops->pin(attach);
1065 EXPORT_SYMBOL_NS_GPL(dma_buf_pin, DMA_BUF);
1068 * dma_buf_unpin - Unpin a DMA-buf
1069 * @attach: [in] attachment which should be unpinned
1071 * This unpins a buffer pinned by dma_buf_pin() and allows the exporter to move
1072 * any mapping of @attach again and inform the importer through
1073 * &dma_buf_attach_ops.move_notify.
1075 void dma_buf_unpin(struct dma_buf_attachment *attach)
1077 struct dma_buf *dmabuf = attach->dmabuf;
1079 WARN_ON(!dma_buf_attachment_is_dynamic(attach));
1081 dma_resv_assert_held(dmabuf->resv);
1083 if (dmabuf->ops->unpin)
1084 dmabuf->ops->unpin(attach);
1086 EXPORT_SYMBOL_NS_GPL(dma_buf_unpin, DMA_BUF);
1089 * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
1090 * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
1092 * @attach: [in] attachment whose scatterlist is to be returned
1093 * @direction: [in] direction of DMA transfer
1095 * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR
1096 * on error. May return -EINTR if it is interrupted by a signal.
1098 * On success, the DMA addresses and lengths in the returned scatterlist are
1099 * PAGE_SIZE aligned.
1101 * A mapping must be unmapped by using dma_buf_unmap_attachment(). Note that
1102 * the underlying backing storage is pinned for as long as a mapping exists,
1103 * therefore users/importers should not hold onto a mapping for undue amounts of
1106 * Important: Dynamic importers must wait for the exclusive fence of the struct
1107 * dma_resv attached to the DMA-BUF first.
1109 struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
1110 enum dma_data_direction direction)
1112 struct sg_table *sg_table;
1117 if (WARN_ON(!attach || !attach->dmabuf))
1118 return ERR_PTR(-EINVAL);
1120 dma_resv_assert_held(attach->dmabuf->resv);
1124 * Two mappings with different directions for the same
1125 * attachment are not allowed.
1127 if (attach->dir != direction &&
1128 attach->dir != DMA_BIDIRECTIONAL)
1129 return ERR_PTR(-EBUSY);
1134 if (dma_buf_is_dynamic(attach->dmabuf)) {
1135 if (!IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY)) {
1136 r = attach->dmabuf->ops->pin(attach);
1142 sg_table = __map_dma_buf(attach, direction);
1144 sg_table = ERR_PTR(-ENOMEM);
1146 if (IS_ERR(sg_table) && dma_buf_is_dynamic(attach->dmabuf) &&
1147 !IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY))
1148 attach->dmabuf->ops->unpin(attach);
1150 if (!IS_ERR(sg_table) && attach->dmabuf->ops->cache_sgt_mapping) {
1151 attach->sgt = sg_table;
1152 attach->dir = direction;
1155 #ifdef CONFIG_DMA_API_DEBUG
1156 if (!IS_ERR(sg_table)) {
1157 struct scatterlist *sg;
1162 for_each_sgtable_dma_sg(sg_table, sg, i) {
1163 addr = sg_dma_address(sg);
1164 len = sg_dma_len(sg);
1165 if (!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(len)) {
1166 pr_debug("%s: addr %llx or len %x is not page aligned!\n",
1167 __func__, addr, len);
1171 #endif /* CONFIG_DMA_API_DEBUG */
1174 EXPORT_SYMBOL_NS_GPL(dma_buf_map_attachment, DMA_BUF);
1177 * dma_buf_map_attachment_unlocked - Returns the scatterlist table of the attachment;
1178 * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
1180 * @attach: [in] attachment whose scatterlist is to be returned
1181 * @direction: [in] direction of DMA transfer
1183 * Unlocked variant of dma_buf_map_attachment().
1186 dma_buf_map_attachment_unlocked(struct dma_buf_attachment *attach,
1187 enum dma_data_direction direction)
1189 struct sg_table *sg_table;
1193 if (WARN_ON(!attach || !attach->dmabuf))
1194 return ERR_PTR(-EINVAL);
1196 dma_resv_lock(attach->dmabuf->resv, NULL);
1197 sg_table = dma_buf_map_attachment(attach, direction);
1198 dma_resv_unlock(attach->dmabuf->resv);
1202 EXPORT_SYMBOL_NS_GPL(dma_buf_map_attachment_unlocked, DMA_BUF);
1205 * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
1206 * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
1208 * @attach: [in] attachment to unmap buffer from
1209 * @sg_table: [in] scatterlist info of the buffer to unmap
1210 * @direction: [in] direction of DMA transfer
1212 * This unmaps a DMA mapping for @attached obtained by dma_buf_map_attachment().
1214 void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
1215 struct sg_table *sg_table,
1216 enum dma_data_direction direction)
1220 if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
1223 dma_resv_assert_held(attach->dmabuf->resv);
1225 if (attach->sgt == sg_table)
1228 __unmap_dma_buf(attach, sg_table, direction);
1230 if (dma_buf_is_dynamic(attach->dmabuf) &&
1231 !IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY))
1232 dma_buf_unpin(attach);
1234 EXPORT_SYMBOL_NS_GPL(dma_buf_unmap_attachment, DMA_BUF);
1237 * dma_buf_unmap_attachment_unlocked - unmaps and decreases usecount of the buffer;might
1238 * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
1240 * @attach: [in] attachment to unmap buffer from
1241 * @sg_table: [in] scatterlist info of the buffer to unmap
1242 * @direction: [in] direction of DMA transfer
1244 * Unlocked variant of dma_buf_unmap_attachment().
1246 void dma_buf_unmap_attachment_unlocked(struct dma_buf_attachment *attach,
1247 struct sg_table *sg_table,
1248 enum dma_data_direction direction)
1252 if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
1255 dma_resv_lock(attach->dmabuf->resv, NULL);
1256 dma_buf_unmap_attachment(attach, sg_table, direction);
1257 dma_resv_unlock(attach->dmabuf->resv);
1259 EXPORT_SYMBOL_NS_GPL(dma_buf_unmap_attachment_unlocked, DMA_BUF);
1262 * dma_buf_move_notify - notify attachments that DMA-buf is moving
1264 * @dmabuf: [in] buffer which is moving
1266 * Informs all attachmenst that they need to destroy and recreated all their
1269 void dma_buf_move_notify(struct dma_buf *dmabuf)
1271 struct dma_buf_attachment *attach;
1273 dma_resv_assert_held(dmabuf->resv);
1275 list_for_each_entry(attach, &dmabuf->attachments, node)
1276 if (attach->importer_ops)
1277 attach->importer_ops->move_notify(attach);
1279 EXPORT_SYMBOL_NS_GPL(dma_buf_move_notify, DMA_BUF);
1284 * There are mutliple reasons for supporting CPU access to a dma buffer object:
1286 * - Fallback operations in the kernel, for example when a device is connected
1287 * over USB and the kernel needs to shuffle the data around first before
1288 * sending it away. Cache coherency is handled by braketing any transactions
1289 * with calls to dma_buf_begin_cpu_access() and dma_buf_end_cpu_access()
1292 * Since for most kernel internal dma-buf accesses need the entire buffer, a
1293 * vmap interface is introduced. Note that on very old 32-bit architectures
1294 * vmalloc space might be limited and result in vmap calls failing.
1298 * void \*dma_buf_vmap(struct dma_buf \*dmabuf, struct iosys_map \*map)
1299 * void dma_buf_vunmap(struct dma_buf \*dmabuf, struct iosys_map \*map)
1301 * The vmap call can fail if there is no vmap support in the exporter, or if
1302 * it runs out of vmalloc space. Note that the dma-buf layer keeps a reference
1303 * count for all vmap access and calls down into the exporter's vmap function
1304 * only when no vmapping exists, and only unmaps it once. Protection against
1305 * concurrent vmap/vunmap calls is provided by taking the &dma_buf.lock mutex.
1307 * - For full compatibility on the importer side with existing userspace
1308 * interfaces, which might already support mmap'ing buffers. This is needed in
1309 * many processing pipelines (e.g. feeding a software rendered image into a
1310 * hardware pipeline, thumbnail creation, snapshots, ...). Also, Android's ION
1311 * framework already supported this and for DMA buffer file descriptors to
1312 * replace ION buffers mmap support was needed.
1314 * There is no special interfaces, userspace simply calls mmap on the dma-buf
1315 * fd. But like for CPU access there's a need to braket the actual access,
1316 * which is handled by the ioctl (DMA_BUF_IOCTL_SYNC). Note that
1317 * DMA_BUF_IOCTL_SYNC can fail with -EAGAIN or -EINTR, in which case it must
1320 * Some systems might need some sort of cache coherency management e.g. when
1321 * CPU and GPU domains are being accessed through dma-buf at the same time.
1322 * To circumvent this problem there are begin/end coherency markers, that
1323 * forward directly to existing dma-buf device drivers vfunc hooks. Userspace
1324 * can make use of those markers through the DMA_BUF_IOCTL_SYNC ioctl. The
1325 * sequence would be used like following:
1328 * - for each drawing/upload cycle in CPU 1. SYNC_START ioctl, 2. read/write
1329 * to mmap area 3. SYNC_END ioctl. This can be repeated as often as you
1330 * want (with the new data being consumed by say the GPU or the scanout
1332 * - munmap once you don't need the buffer any more
1334 * For correctness and optimal performance, it is always required to use
1335 * SYNC_START and SYNC_END before and after, respectively, when accessing the
1336 * mapped address. Userspace cannot rely on coherent access, even when there
1337 * are systems where it just works without calling these ioctls.
1339 * - And as a CPU fallback in userspace processing pipelines.
1341 * Similar to the motivation for kernel cpu access it is again important that
1342 * the userspace code of a given importing subsystem can use the same
1343 * interfaces with a imported dma-buf buffer object as with a native buffer
1344 * object. This is especially important for drm where the userspace part of
1345 * contemporary OpenGL, X, and other drivers is huge, and reworking them to
1346 * use a different way to mmap a buffer rather invasive.
1348 * The assumption in the current dma-buf interfaces is that redirecting the
1349 * initial mmap is all that's needed. A survey of some of the existing
1350 * subsystems shows that no driver seems to do any nefarious thing like
1351 * syncing up with outstanding asynchronous processing on the device or
1352 * allocating special resources at fault time. So hopefully this is good
1353 * enough, since adding interfaces to intercept pagefaults and allow pte
1354 * shootdowns would increase the complexity quite a bit.
1358 * int dma_buf_mmap(struct dma_buf \*, struct vm_area_struct \*,
1361 * If the importing subsystem simply provides a special-purpose mmap call to
1362 * set up a mapping in userspace, calling do_mmap with &dma_buf.file will
1363 * equally achieve that for a dma-buf object.
1366 static int __dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
1367 enum dma_data_direction direction)
1369 bool write = (direction == DMA_BIDIRECTIONAL ||
1370 direction == DMA_TO_DEVICE);
1371 struct dma_resv *resv = dmabuf->resv;
1374 /* Wait on any implicit rendering fences */
1375 ret = dma_resv_wait_timeout(resv, dma_resv_usage_rw(write),
1376 true, MAX_SCHEDULE_TIMEOUT);
1384 * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
1385 * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
1386 * preparations. Coherency is only guaranteed in the specified range for the
1387 * specified access direction.
1388 * @dmabuf: [in] buffer to prepare cpu access for.
1389 * @direction: [in] length of range for cpu access.
1391 * After the cpu access is complete the caller should call
1392 * dma_buf_end_cpu_access(). Only when cpu access is braketed by both calls is
1393 * it guaranteed to be coherent with other DMA access.
1395 * This function will also wait for any DMA transactions tracked through
1396 * implicit synchronization in &dma_buf.resv. For DMA transactions with explicit
1397 * synchronization this function will only ensure cache coherency, callers must
1398 * ensure synchronization with such DMA transactions on their own.
1400 * Can return negative error values, returns 0 on success.
1402 int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
1403 enum dma_data_direction direction)
1407 if (WARN_ON(!dmabuf))
1410 might_lock(&dmabuf->resv->lock.base);
1412 if (dmabuf->ops->begin_cpu_access)
1413 ret = dmabuf->ops->begin_cpu_access(dmabuf, direction);
1415 /* Ensure that all fences are waited upon - but we first allow
1416 * the native handler the chance to do so more efficiently if it
1417 * chooses. A double invocation here will be reasonably cheap no-op.
1420 ret = __dma_buf_begin_cpu_access(dmabuf, direction);
1424 EXPORT_SYMBOL_NS_GPL(dma_buf_begin_cpu_access, DMA_BUF);
1427 * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
1428 * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
1429 * actions. Coherency is only guaranteed in the specified range for the
1430 * specified access direction.
1431 * @dmabuf: [in] buffer to complete cpu access for.
1432 * @direction: [in] length of range for cpu access.
1434 * This terminates CPU access started with dma_buf_begin_cpu_access().
1436 * Can return negative error values, returns 0 on success.
1438 int dma_buf_end_cpu_access(struct dma_buf *dmabuf,
1439 enum dma_data_direction direction)
1445 might_lock(&dmabuf->resv->lock.base);
1447 if (dmabuf->ops->end_cpu_access)
1448 ret = dmabuf->ops->end_cpu_access(dmabuf, direction);
1452 EXPORT_SYMBOL_NS_GPL(dma_buf_end_cpu_access, DMA_BUF);
1456 * dma_buf_mmap - Setup up a userspace mmap with the given vma
1457 * @dmabuf: [in] buffer that should back the vma
1458 * @vma: [in] vma for the mmap
1459 * @pgoff: [in] offset in pages where this mmap should start within the
1462 * This function adjusts the passed in vma so that it points at the file of the
1463 * dma_buf operation. It also adjusts the starting pgoff and does bounds
1464 * checking on the size of the vma. Then it calls the exporters mmap function to
1465 * set up the mapping.
1467 * Can return negative error values, returns 0 on success.
1469 int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
1470 unsigned long pgoff)
1474 if (WARN_ON(!dmabuf || !vma))
1477 /* check if buffer supports mmap */
1478 if (!dmabuf->ops->mmap)
1481 /* check for offset overflow */
1482 if (pgoff + vma_pages(vma) < pgoff)
1485 /* check for overflowing the buffer's size */
1486 if (pgoff + vma_pages(vma) >
1487 dmabuf->size >> PAGE_SHIFT)
1490 /* readjust the vma */
1491 vma_set_file(vma, dmabuf->file);
1492 vma->vm_pgoff = pgoff;
1494 dma_resv_lock(dmabuf->resv, NULL);
1495 ret = dmabuf->ops->mmap(dmabuf, vma);
1496 dma_resv_unlock(dmabuf->resv);
1500 EXPORT_SYMBOL_NS_GPL(dma_buf_mmap, DMA_BUF);
1503 * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
1504 * address space. Same restrictions as for vmap and friends apply.
1505 * @dmabuf: [in] buffer to vmap
1506 * @map: [out] returns the vmap pointer
1508 * This call may fail due to lack of virtual mapping address space.
1509 * These calls are optional in drivers. The intended use for them
1510 * is for mapping objects linear in kernel space for high use objects.
1512 * To ensure coherency users must call dma_buf_begin_cpu_access() and
1513 * dma_buf_end_cpu_access() around any cpu access performed through this
1516 * Returns 0 on success, or a negative errno code otherwise.
1518 int dma_buf_vmap(struct dma_buf *dmabuf, struct iosys_map *map)
1520 struct iosys_map ptr;
1523 iosys_map_clear(map);
1525 if (WARN_ON(!dmabuf))
1528 dma_resv_assert_held(dmabuf->resv);
1530 if (!dmabuf->ops->vmap)
1533 if (dmabuf->vmapping_counter) {
1534 dmabuf->vmapping_counter++;
1535 BUG_ON(iosys_map_is_null(&dmabuf->vmap_ptr));
1536 *map = dmabuf->vmap_ptr;
1540 BUG_ON(iosys_map_is_set(&dmabuf->vmap_ptr));
1542 ret = dmabuf->ops->vmap(dmabuf, &ptr);
1543 if (WARN_ON_ONCE(ret))
1546 dmabuf->vmap_ptr = ptr;
1547 dmabuf->vmapping_counter = 1;
1549 *map = dmabuf->vmap_ptr;
1553 EXPORT_SYMBOL_NS_GPL(dma_buf_vmap, DMA_BUF);
1556 * dma_buf_vmap_unlocked - Create virtual mapping for the buffer object into kernel
1557 * address space. Same restrictions as for vmap and friends apply.
1558 * @dmabuf: [in] buffer to vmap
1559 * @map: [out] returns the vmap pointer
1561 * Unlocked version of dma_buf_vmap()
1563 * Returns 0 on success, or a negative errno code otherwise.
1565 int dma_buf_vmap_unlocked(struct dma_buf *dmabuf, struct iosys_map *map)
1569 iosys_map_clear(map);
1571 if (WARN_ON(!dmabuf))
1574 dma_resv_lock(dmabuf->resv, NULL);
1575 ret = dma_buf_vmap(dmabuf, map);
1576 dma_resv_unlock(dmabuf->resv);
1580 EXPORT_SYMBOL_NS_GPL(dma_buf_vmap_unlocked, DMA_BUF);
1583 * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
1584 * @dmabuf: [in] buffer to vunmap
1585 * @map: [in] vmap pointer to vunmap
1587 void dma_buf_vunmap(struct dma_buf *dmabuf, struct iosys_map *map)
1589 if (WARN_ON(!dmabuf))
1592 dma_resv_assert_held(dmabuf->resv);
1594 BUG_ON(iosys_map_is_null(&dmabuf->vmap_ptr));
1595 BUG_ON(dmabuf->vmapping_counter == 0);
1596 BUG_ON(!iosys_map_is_equal(&dmabuf->vmap_ptr, map));
1598 if (--dmabuf->vmapping_counter == 0) {
1599 if (dmabuf->ops->vunmap)
1600 dmabuf->ops->vunmap(dmabuf, map);
1601 iosys_map_clear(&dmabuf->vmap_ptr);
1604 EXPORT_SYMBOL_NS_GPL(dma_buf_vunmap, DMA_BUF);
1607 * dma_buf_vunmap_unlocked - Unmap a vmap obtained by dma_buf_vmap.
1608 * @dmabuf: [in] buffer to vunmap
1609 * @map: [in] vmap pointer to vunmap
1611 void dma_buf_vunmap_unlocked(struct dma_buf *dmabuf, struct iosys_map *map)
1613 if (WARN_ON(!dmabuf))
1616 dma_resv_lock(dmabuf->resv, NULL);
1617 dma_buf_vunmap(dmabuf, map);
1618 dma_resv_unlock(dmabuf->resv);
1620 EXPORT_SYMBOL_NS_GPL(dma_buf_vunmap_unlocked, DMA_BUF);
1622 #ifdef CONFIG_DEBUG_FS
1623 static int dma_buf_debug_show(struct seq_file *s, void *unused)
1625 struct dma_buf *buf_obj;
1626 struct dma_buf_attachment *attach_obj;
1627 int count = 0, attach_count;
1631 ret = mutex_lock_interruptible(&db_list.lock);
1636 seq_puts(s, "\nDma-buf Objects:\n");
1637 seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\t%-8s\tname\n",
1638 "size", "flags", "mode", "count", "ino");
1640 list_for_each_entry(buf_obj, &db_list.head, list_node) {
1642 ret = dma_resv_lock_interruptible(buf_obj->resv, NULL);
1647 spin_lock(&buf_obj->name_lock);
1648 seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\n",
1650 buf_obj->file->f_flags, buf_obj->file->f_mode,
1651 file_count(buf_obj->file),
1653 file_inode(buf_obj->file)->i_ino,
1654 buf_obj->name ?: "<none>");
1655 spin_unlock(&buf_obj->name_lock);
1657 dma_resv_describe(buf_obj->resv, s);
1659 seq_puts(s, "\tAttached Devices:\n");
1662 list_for_each_entry(attach_obj, &buf_obj->attachments, node) {
1663 seq_printf(s, "\t%s\n", dev_name(attach_obj->dev));
1666 dma_resv_unlock(buf_obj->resv);
1668 seq_printf(s, "Total %d devices attached\n\n",
1672 size += buf_obj->size;
1675 seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size);
1677 mutex_unlock(&db_list.lock);
1681 mutex_unlock(&db_list.lock);
1685 DEFINE_SHOW_ATTRIBUTE(dma_buf_debug);
1687 static struct dentry *dma_buf_debugfs_dir;
1689 static int dma_buf_init_debugfs(void)
1694 d = debugfs_create_dir("dma_buf", NULL);
1698 dma_buf_debugfs_dir = d;
1700 d = debugfs_create_file("bufinfo", S_IRUGO, dma_buf_debugfs_dir,
1701 NULL, &dma_buf_debug_fops);
1703 pr_debug("dma_buf: debugfs: failed to create node bufinfo\n");
1704 debugfs_remove_recursive(dma_buf_debugfs_dir);
1705 dma_buf_debugfs_dir = NULL;
1712 static void dma_buf_uninit_debugfs(void)
1714 debugfs_remove_recursive(dma_buf_debugfs_dir);
1717 static inline int dma_buf_init_debugfs(void)
1721 static inline void dma_buf_uninit_debugfs(void)
1726 static int __init dma_buf_init(void)
1730 ret = dma_buf_init_sysfs_statistics();
1734 dma_buf_mnt = kern_mount(&dma_buf_fs_type);
1735 if (IS_ERR(dma_buf_mnt))
1736 return PTR_ERR(dma_buf_mnt);
1738 mutex_init(&db_list.lock);
1739 INIT_LIST_HEAD(&db_list.head);
1740 dma_buf_init_debugfs();
1743 subsys_initcall(dma_buf_init);
1745 static void __exit dma_buf_deinit(void)
1747 dma_buf_uninit_debugfs();
1748 kern_unmount(dma_buf_mnt);
1749 dma_buf_uninit_sysfs_statistics();
1751 __exitcall(dma_buf_deinit);