// SPDX-License-Identifier: GPL-2.0-only /* * drivers/dma-buf/sync_file.c * * Copyright (C) 2012 Google, Inc. */ #include <linux/dma-fence-unwrap.h> #include <linux/export.h> #include <linux/file.h> #include <linux/fs.h> #include <linux/kernel.h> #include <linux/poll.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/uaccess.h> #include <linux/anon_inodes.h> #include <linux/sync_file.h> #include <uapi/linux/sync_file.h> static const struct file_operations sync_file_fops; static struct sync_file *sync_file_alloc(void) { struct sync_file *sync_file; sync_file = kzalloc(sizeof(*sync_file), GFP_KERNEL); if (!sync_file) return NULL; sync_file->file = anon_inode_getfile("sync_file", &sync_file_fops, sync_file, 0); if (IS_ERR(sync_file->file)) goto err; init_waitqueue_head(&sync_file->wq); INIT_LIST_HEAD(&sync_file->cb.node); return sync_file; err: kfree(sync_file); return NULL; } static void fence_check_cb_func(struct dma_fence *f, struct dma_fence_cb *cb) { struct sync_file *sync_file; sync_file = container_of(cb, struct sync_file, cb); wake_up_all(&sync_file->wq); } /** * sync_file_create() - creates a sync file * @fence: fence to add to the sync_fence * * Creates a sync_file containg @fence. This function acquires and additional * reference of @fence for the newly-created &sync_file, if it succeeds. The * sync_file can be released with fput(sync_file->file). Returns the * sync_file or NULL in case of error. */ struct sync_file *sync_file_create(struct dma_fence *fence) { struct sync_file *sync_file; sync_file = sync_file_alloc(); if (!sync_file) return NULL; sync_file->fence = dma_fence_get(fence); return sync_file; } EXPORT_SYMBOL(sync_file_create); static struct sync_file *sync_file_fdget(int fd) { struct file *file = fget(fd); if (!file) return NULL; if (file->f_op != &sync_file_fops) goto err; return file->private_data; err: fput(file); return NULL; } /** * sync_file_get_fence - get the fence related to the sync_file fd * @fd: sync_file fd to get the fence from * * Ensures @fd references a valid sync_file and returns a fence that * represents all fence in the sync_file. On error NULL is returned. */ struct dma_fence *sync_file_get_fence(int fd) { struct sync_file *sync_file; struct dma_fence *fence; sync_file = sync_file_fdget(fd); if (!sync_file) return NULL; fence = dma_fence_get(sync_file->fence); fput(sync_file->file); return fence; } EXPORT_SYMBOL(sync_file_get_fence); /** * sync_file_get_name - get the name of the sync_file * @sync_file: sync_file to get the fence from * @buf: destination buffer to copy sync_file name into * @len: available size of destination buffer. * * Each sync_file may have a name assigned either by the user (when merging * sync_files together) or created from the fence it contains. In the latter * case construction of the name is deferred until use, and so requires * sync_file_get_name(). * * Returns: a string representing the name. */ char *sync_file_get_name(struct sync_file *sync_file, char *buf, int len) { if (sync_file->user_name[0]) { strlcpy(buf, sync_file->user_name, len); } else { struct dma_fence *fence = sync_file->fence; snprintf(buf, len, "%s-%s%llu-%lld", fence->ops->get_driver_name(fence), fence->ops->get_timeline_name(fence), fence->context, fence->seqno); } return buf; } /** * sync_file_merge() - merge two sync_files * @name: name of new fence * @a: sync_file a * @b: sync_file b * * Creates a new sync_file which contains copies of all the fences in both * @a and @b. @a and @b remain valid, independent sync_file. Returns the * new merged sync_file or NULL in case of error. */ static struct sync_file *sync_file_merge(const char *name, struct sync_file *a, struct sync_file *b) { struct sync_file *sync_file; struct dma_fence *fence; sync_file = sync_file_alloc(); if (!sync_file) return NULL; fence = dma_fence_unwrap_merge(a->fence, b->fence); if (!fence) { fput(sync_file->file); return NULL; } sync_file->fence = fence; strlcpy(sync_file->user_name, name, sizeof(sync_file->user_name)); return sync_file; } static int sync_file_release(struct inode *inode, struct file *file) { struct sync_file *sync_file = file->private_data; if (test_bit(POLL_ENABLED, &sync_file->flags)) dma_fence_remove_callback(sync_file->fence, &sync_file->cb); dma_fence_put(sync_file->fence); kfree(sync_file); return 0; } static __poll_t sync_file_poll(struct file *file, poll_table *wait) { struct sync_file *sync_file = file->private_data; poll_wait(file, &sync_file->wq, wait); if (list_empty(&sync_file->cb.node) && !test_and_set_bit(POLL_ENABLED, &sync_file->flags)) { if (dma_fence_add_callback(sync_file->fence, &sync_file->cb, fence_check_cb_func) < 0) wake_up_all(&sync_file->wq); } return dma_fence_is_signaled(sync_file->fence) ? EPOLLIN : 0; } static long sync_file_ioctl_merge(struct sync_file *sync_file, unsigned long arg) { int fd = get_unused_fd_flags(O_CLOEXEC); int err; struct sync_file *fence2, *fence3; struct sync_merge_data data; if (fd < 0) return fd; if (copy_from_user(&data, (void __user *)arg, sizeof(data))) { err = -EFAULT; goto err_put_fd; } if (data.flags || data.pad) { err = -EINVAL; goto err_put_fd; } fence2 = sync_file_fdget(data.fd2); if (!fence2) { err = -ENOENT; goto err_put_fd; } data.name[sizeof(data.name) - 1] = '\0'; fence3 = sync_file_merge(data.name, sync_file, fence2); if (!fence3) { err = -ENOMEM; goto err_put_fence2; } data.fence = fd; if (copy_to_user((void __user *)arg, &data, sizeof(data))) { err = -EFAULT; goto err_put_fence3; } fd_install(fd, fence3->file); fput(fence2->file); return 0; err_put_fence3: fput(fence3->file); err_put_fence2: fput(fence2->file); err_put_fd: put_unused_fd(fd); return err; } static int sync_fill_fence_info(struct dma_fence *fence, struct sync_fence_info *info) { strlcpy(info->obj_name, fence->ops->get_timeline_name(fence), sizeof(info->obj_name)); strlcpy(info->driver_name, fence->ops->get_driver_name(fence), sizeof(info->driver_name)); info->status = dma_fence_get_status(fence); while (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags) && !test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags)) cpu_relax(); info->timestamp_ns = test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags) ? ktime_to_ns(fence->timestamp) : ktime_set(0, 0); return info->status; } static long sync_file_ioctl_fence_info(struct sync_file *sync_file, unsigned long arg) { struct sync_fence_info *fence_info = NULL; struct dma_fence_unwrap iter; struct sync_file_info info; unsigned int num_fences; struct dma_fence *fence; int ret; __u32 size; if (copy_from_user(&info, (void __user *)arg, sizeof(info))) return -EFAULT; if (info.flags || info.pad) return -EINVAL; num_fences = 0; dma_fence_unwrap_for_each(fence, &iter, sync_file->fence) ++num_fences; /* * Passing num_fences = 0 means that userspace doesn't want to * retrieve any sync_fence_info. If num_fences = 0 we skip filling * sync_fence_info and return the actual number of fences on * info->num_fences. */ if (!info.num_fences) { info.status = dma_fence_get_status(sync_file->fence); goto no_fences; } else { info.status = 1; } if (info.num_fences < num_fences) return -EINVAL; size = num_fences * sizeof(*fence_info); fence_info = kzalloc(size, GFP_KERNEL); if (!fence_info) return -ENOMEM; num_fences = 0; dma_fence_unwrap_for_each(fence, &iter, sync_file->fence) { int status; status = sync_fill_fence_info(fence, &fence_info[num_fences++]); info.status = info.status <= 0 ? info.status : status; } if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info, size)) { ret = -EFAULT; goto out; } no_fences: sync_file_get_name(sync_file, info.name, sizeof(info.name)); info.num_fences = num_fences; if (copy_to_user((void __user *)arg, &info, sizeof(info))) ret = -EFAULT; else ret = 0; out: kfree(fence_info); return ret; } static long sync_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct sync_file *sync_file = file->private_data; switch (cmd) { case SYNC_IOC_MERGE: return sync_file_ioctl_merge(sync_file, arg); case SYNC_IOC_FILE_INFO: return sync_file_ioctl_fence_info(sync_file, arg); default: return -ENOTTY; } } static const struct file_operations sync_file_fops = { .release = sync_file_release, .poll = sync_file_poll, .unlocked_ioctl = sync_file_ioctl, .compat_ioctl = compat_ptr_ioctl, };