1 #ifndef __LINUX_UIO_H 2 #define __LINUX_UIO_H 3 4 #include <linux/compiler.h> 5 #include <linux/types.h> 6 7 /* 8 * Berkeley style UIO structures - Alan Cox 1994. 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * as published by the Free Software Foundation; either version 13 * 2 of the License, or (at your option) any later version. 14 */ 15 16 struct iovec 17 { 18 void __user *iov_base; /* BSD uses caddr_t (1003.1g requires void *) */ 19 __kernel_size_t iov_len; /* Must be size_t (1003.1g) */ 20 }; 21 22 #ifdef __KERNEL__ 23 24 struct kvec { 25 void *iov_base; /* and that should *never* hold a userland pointer */ 26 size_t iov_len; 27 }; 28 29 #endif 30 31 /* 32 * UIO_MAXIOV shall be at least 16 1003.1g (5.4.1.1) 33 */ 34 35 #define UIO_FASTIOV 8 36 #define UIO_MAXIOV 1024 37 38 /* 39 * Total number of bytes covered by an iovec. 40 * 41 * NOTE that it is not safe to use this function until all the iovec's 42 * segment lengths have been validated. Because the individual lengths can 43 * overflow a size_t when added together. 44 */ iov_length(const struct iovec * iov,unsigned long nr_segs)45 static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs) 46 { 47 unsigned long seg; 48 size_t ret = 0; 49 50 for (seg = 0; seg < nr_segs; seg++) 51 ret += iov[seg].iov_len; 52 return ret; 53 } 54 55 unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to); 56 57 #endif 58