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checksum_wrappers_64.c
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1 /*
2  * This program is free software; you can redistribute it and/or modify
3  * it under the terms of the GNU General Public License as published by
4  * the Free Software Foundation; either version 2 of the License, or
5  * (at your option) any later version.
6  *
7  * This program is distributed in the hope that it will be useful,
8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10  * GNU General Public License for more details.
11  *
12  * You should have received a copy of the GNU General Public License
13  * along with this program; if not, write to the Free Software
14  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
15  *
16  * Copyright (C) IBM Corporation, 2010
17  *
18  * Author: Anton Blanchard <[email protected]>
19  */
20 #include <linux/export.h>
21 #include <linux/compiler.h>
22 #include <linux/types.h>
23 #include <asm/checksum.h>
24 #include <asm/uaccess.h>
25 
26 __wsum csum_and_copy_from_user(const void __user *src, void *dst,
27  int len, __wsum sum, int *err_ptr)
28 {
29  unsigned int csum;
30 
31  might_sleep();
32 
33  *err_ptr = 0;
34 
35  if (!len) {
36  csum = 0;
37  goto out;
38  }
39 
40  if (unlikely((len < 0) || !access_ok(VERIFY_READ, src, len))) {
41  *err_ptr = -EFAULT;
42  csum = (__force unsigned int)sum;
43  goto out;
44  }
45 
46  csum = csum_partial_copy_generic((void __force *)src, dst,
47  len, sum, err_ptr, NULL);
48 
49  if (unlikely(*err_ptr)) {
50  int missing = __copy_from_user(dst, src, len);
51 
52  if (missing) {
53  memset(dst + len - missing, 0, missing);
54  *err_ptr = -EFAULT;
55  } else {
56  *err_ptr = 0;
57  }
58 
59  csum = csum_partial(dst, len, sum);
60  }
61 
62 out:
63  return (__force __wsum)csum;
64 }
66 
67 __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
68  __wsum sum, int *err_ptr)
69 {
70  unsigned int csum;
71 
72  might_sleep();
73 
74  *err_ptr = 0;
75 
76  if (!len) {
77  csum = 0;
78  goto out;
79  }
80 
81  if (unlikely((len < 0) || !access_ok(VERIFY_WRITE, dst, len))) {
82  *err_ptr = -EFAULT;
83  csum = -1; /* invalid checksum */
84  goto out;
85  }
86 
87  csum = csum_partial_copy_generic(src, (void __force *)dst,
88  len, sum, NULL, err_ptr);
89 
90  if (unlikely(*err_ptr)) {
91  csum = csum_partial(src, len, sum);
92 
93  if (copy_to_user(dst, src, len)) {
94  *err_ptr = -EFAULT;
95  csum = -1; /* invalid checksum */
96  }
97  }
98 
99 out:
100  return (__force __wsum)csum;
101 }