include/linux/uio.h

   1 /*
   2  *      Berkeley style UIO structures   -       Alan Cox 1994.
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  */
   9 #ifndef __LINUX_UIO_H
  10 #define __LINUX_UIO_H
  11
  12 #include <uapi/linux/uio.h>
  13
  14
  15 struct kvec {
  16         void *iov_base; /* and that should *never* hold a userland pointer */
  17         size_t iov_len;
  18 };
  19
  20 /*
  21  * Total number of bytes covered by an iovec.
  22  *
  23  * NOTE that it is not safe to use this function until all the iovec's
  24  * segment lengths have been validated.  Because the individual lengths can
  25  * overflow a size_t when added together.
  26  */
  27 static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
  28 {
  29         unsigned long seg;
  30         size_t ret = 0;
  31
  32         for (seg = 0; seg < nr_segs; seg++)
  33                 ret += iov[seg].iov_len;
  34         return ret;
  35 }
  36
  37 unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
  38 #endif