1 #ifndef __LINUX_UIO_H 2 #define __LINUX_UIO_H 3 4 #include <linux/types.h> 5 6 /* 7 * Berkeley style UIO structures - Alan Cox 1994. 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License 11 * as published by the Free Software Foundation; either version 12 * 2 of the License, or (at your option) any later version. 13 */ 14 15 struct iovec 16 { 17 void *iov_base; /* BSD uses caddr_t (1003.1g requires void *) */ 18 __kernel_size_t iov_len; /* Must be size_t (1003.1g) */ 19 }; 20 21 22 /* 23 * UIO_MAXIOV shall be at least 16 1003.1g (5.4.1.1) 24 */ 25 26 #define UIO_FASTIOV 8 27 #define UIO_MAXIOV 1024 28 29 /* 30 * Total number of bytes covered by an iovec. 31 * 32 * NOTE that it is not safe to use this function until all the iovec's 33 * segment lengths have been validated. Because the individual lengths can 34 * overflow a size_t when added together. 35 */ iov_length(const struct iovec * iov,unsigned long nr_segs)36static __inline__ size_t iov_length(const struct iovec *iov, unsigned long nr_segs) 37 { 38 unsigned long seg; 39 size_t ret = 0; 40 41 for (seg = 0; seg < nr_segs; seg++) 42 ret += iov[seg].iov_len; 43 return ret; 44 } 45 46 unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to); 47 48 #endif 49