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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Nathan Scott7b718762005-11-02 14:58:39 +11002 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 *
Nathan Scott7b718762005-11-02 14:58:39 +11005 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 * published by the Free Software Foundation.
8 *
Nathan Scott7b718762005-11-02 14:58:39 +11009 * 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.
Linus Torvalds1da177e2005-04-16 15:20:36 -070013 *
Nathan Scott7b718762005-11-02 14:58:39 +110014 * 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070017 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#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
25uio_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}