hypfs: switch to read_iter/write_iter

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/s390/hypfs/inode.c

@@ -144,36 +144,32 @@ static int hypfs_open(struct inode *inode, struct file *filp)
 	return nonseekable_open(inode, filp);
 }
 
-static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
-			      unsigned long nr_segs, loff_t offset)
+static ssize_t hypfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
-	char *data;
-	ssize_t ret;
-	struct file *filp = iocb->ki_filp;
-	/* XXX: temporary */
-	char __user *buf = iov[0].iov_base;
-	size_t count = iov[0].iov_len;
-
-	if (nr_segs != 1)
-		return -EINVAL;
-
-	data = filp->private_data;
-	ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data));
-	if (ret <= 0)
-		return ret;
+	struct file *file = iocb->ki_filp;
+	char *data = file->private_data;
+	size_t available = strlen(data);
+	loff_t pos = iocb->ki_pos;
+	size_t count;
 
-	iocb->ki_pos += ret;
-	file_accessed(filp);
-
-	return ret;
+	if (pos < 0)
+		return -EINVAL;
+	if (pos >= available || !iov_iter_count(to))
+		return 0;
+	count = copy_to_iter(data + pos, available - pos, to);
+	if (!count)
+		return -EFAULT;
+	iocb->ki_pos = pos + count;
+	file_accessed(file);
+	return count;
 }
-static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
-			      unsigned long nr_segs, loff_t offset)
+
+static ssize_t hypfs_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
 	int rc;
 	struct super_block *sb = file_inode(iocb->ki_filp)->i_sb;
 	struct hypfs_sb_info *fs_info = sb->s_fs_info;
-	size_t count = iov_length(iov, nr_segs);
+	size_t count = iov_iter_count(from);
 
 	/*
 	 * Currently we only allow one update per second for two reasons:
@@ -202,6 +198,7 @@ static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
 	}
 	hypfs_update_update(sb);
 	rc = count;
+	iov_iter_advance(from, count);
 out:
 	mutex_unlock(&fs_info->lock);
 	return rc;
@@ -440,10 +437,10 @@ struct dentry *hypfs_create_str(struct dentry *dir,
 static const struct file_operations hypfs_file_ops = {
 	.open		= hypfs_open,
 	.release	= hypfs_release,
-	.read		= do_sync_read,
-	.write		= do_sync_write,
-	.aio_read	= hypfs_aio_read,
-	.aio_write	= hypfs_aio_write,
+	.read		= new_sync_read,
+	.write		= new_sync_write,
+	.read_iter	= hypfs_read_iter,
+	.write_iter	= hypfs_write_iter,
 	.llseek		= no_llseek,
 };