Linux Kernel  3.7.1
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checksum.c
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1 /*
2  * This program is free software; you can redistribute it and/or
3  * modify it under the terms of the GNU General Public License
4  * as published by the Free Software Foundation; either version
5  * 2 of the License, or (at your option) any later version.
6  */
7 #include <linux/module.h>
8 #include <net/checksum.h>
9 
10 #include <asm/byteorder.h>
11 
12 /*
13  * copy from fs while checksumming, otherwise like csum_partial
14  */
15 __wsum
16 csum_partial_copy_from_user(const void __user *src, void *dst, int len,
17  __wsum sum, int *csum_err)
18 {
19  int missing;
20 
21  missing = __copy_from_user(dst, src, len);
22  if (missing) {
23  memset(dst + len - missing, 0, missing);
24  *csum_err = -EFAULT;
25  } else
26  *csum_err = 0;
27 
28  return csum_partial(dst, len, sum);
29 }
31 
32 /* These are from csum_64plus.S */