1/*
2 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17 */
18#include <xfs.h>
19
20/* Read from kernel buffer at src to user/kernel buffer defined
21 * by the uio structure. Advance the pointer in the uio struct
22 * as we go.
23 */
24int
25xfs_uio_read(caddr_t src, size_t len, struct uio *uio)
26{
27	size_t	count;
28
29	if (!len || !uio->uio_resid)
30		return 0;
31
32	count = uio->uio_iov->iov_len;
33	if (!count)
34		return 0;
35	if (count > len)
36		count = len;
37
38	if (uio->uio_segflg == UIO_USERSPACE) {
39		if (copy_to_user(uio->uio_iov->iov_base, src, count))
40			return EFAULT;
41	} else {
42		ASSERT(uio->uio_segflg == UIO_SYSSPACE);
43		memcpy(uio->uio_iov->iov_base, src, count);
44	}
45
46	uio->uio_iov->iov_base = (void*)((char*)uio->uio_iov->iov_base + count);
47	uio->uio_iov->iov_len -= count;
48	uio->uio_offset += count;
49	uio->uio_resid -= count;
50	return 0;
51}
52