1 files changed, 372 insertions, 0 deletions
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
new file mode 100644
index 0000000000..2e9a316c59
--- /dev/null
+++ b/drivers/dma-buf/sync_file.c
@@ -0,0 +1,372 @@
+// 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]) {
+		strscpy(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;
+	strscpy(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)
+{
+	strscpy(info->obj_name, fence->ops->get_timeline_name(fence),
+		sizeof(info->obj_name));
+	strscpy(info->driver_name, fence->ops->get_driver_name(fence),
+		sizeof(info->driver_name));
+
+	info->status = dma_fence_get_status(fence);
+	info->timestamp_ns =
+		dma_fence_is_signaled(fence) ?
+			ktime_to_ns(dma_fence_timestamp(fence)) :
+			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,
+};