diff options
Diffstat (limited to '')
-rw-r--r-- | drivers/dma-buf/sync_file.c | 485 |
1 files changed, 485 insertions, 0 deletions
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c new file mode 100644 index 000000000..f0c822952 --- /dev/null +++ b/drivers/dma-buf/sync_file.c @@ -0,0 +1,485 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * drivers/dma-buf/sync_file.c + * + * Copyright (C) 2012 Google, Inc. + */ + +#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; +} + +static int sync_file_set_fence(struct sync_file *sync_file, + struct dma_fence **fences, int num_fences) +{ + struct dma_fence_array *array; + + /* + * The reference for the fences in the new sync_file and held + * in add_fence() during the merge procedure, so for num_fences == 1 + * we already own a new reference to the fence. For num_fence > 1 + * we own the reference of the dma_fence_array creation. + */ + if (num_fences == 1) { + sync_file->fence = fences[0]; + kfree(fences); + } else { + array = dma_fence_array_create(num_fences, fences, + dma_fence_context_alloc(1), + 1, false); + if (!array) + return -ENOMEM; + + sync_file->fence = &array->base; + } + + return 0; +} + +static struct dma_fence **get_fences(struct sync_file *sync_file, + int *num_fences) +{ + if (dma_fence_is_array(sync_file->fence)) { + struct dma_fence_array *array = to_dma_fence_array(sync_file->fence); + + *num_fences = array->num_fences; + return array->fences; + } + + *num_fences = 1; + return &sync_file->fence; +} + +static void add_fence(struct dma_fence **fences, + int *i, struct dma_fence *fence) +{ + fences[*i] = fence; + + if (!dma_fence_is_signaled(fence)) { + dma_fence_get(fence); + (*i)++; + } +} + +/** + * 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 **fences = NULL, **nfences, **a_fences, **b_fences; + int i = 0, i_a, i_b, num_fences, a_num_fences, b_num_fences; + + sync_file = sync_file_alloc(); + if (!sync_file) + return NULL; + + a_fences = get_fences(a, &a_num_fences); + b_fences = get_fences(b, &b_num_fences); + if (a_num_fences > INT_MAX - b_num_fences) + goto err; + + num_fences = a_num_fences + b_num_fences; + + fences = kcalloc(num_fences, sizeof(*fences), GFP_KERNEL); + if (!fences) + goto err; + + /* + * Assume sync_file a and b are both ordered and have no + * duplicates with the same context. + * + * If a sync_file can only be created with sync_file_merge + * and sync_file_create, this is a reasonable assumption. + */ + for (i_a = i_b = 0; i_a < a_num_fences && i_b < b_num_fences; ) { + struct dma_fence *pt_a = a_fences[i_a]; + struct dma_fence *pt_b = b_fences[i_b]; + + if (pt_a->context < pt_b->context) { + add_fence(fences, &i, pt_a); + + i_a++; + } else if (pt_a->context > pt_b->context) { + add_fence(fences, &i, pt_b); + + i_b++; + } else { + if (__dma_fence_is_later(pt_a->seqno, pt_b->seqno, + pt_a->ops)) + add_fence(fences, &i, pt_a); + else + add_fence(fences, &i, pt_b); + + i_a++; + i_b++; + } + } + + for (; i_a < a_num_fences; i_a++) + add_fence(fences, &i, a_fences[i_a]); + + for (; i_b < b_num_fences; i_b++) + add_fence(fences, &i, b_fences[i_b]); + + if (i == 0) + fences[i++] = dma_fence_get(a_fences[0]); + + if (num_fences > i) { + nfences = krealloc(fences, i * sizeof(*fences), + GFP_KERNEL); + if (!nfences) + goto err; + + fences = nfences; + } + + if (sync_file_set_fence(sync_file, fences, i) < 0) + goto err; + + strlcpy(sync_file->user_name, name, sizeof(sync_file->user_name)); + return sync_file; + +err: + while (i) + dma_fence_put(fences[--i]); + kfree(fences); + fput(sync_file->file); + return NULL; + +} + +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_file_info info; + struct sync_fence_info *fence_info = NULL; + struct dma_fence **fences; + __u32 size; + int num_fences, ret, i; + + if (copy_from_user(&info, (void __user *)arg, sizeof(info))) + return -EFAULT; + + if (info.flags || info.pad) + return -EINVAL; + + fences = get_fences(sync_file, &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; + + for (i = 0; i < num_fences; i++) { + int status = sync_fill_fence_info(fences[i], &fence_info[i]); + 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, +}; |