diff options
Diffstat (limited to 'include/linux/uio.h')
-rw-r--r-- | include/linux/uio.h | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/include/linux/uio.h b/include/linux/uio.h new file mode 100644 index 00000000..98c11432 --- /dev/null +++ b/include/linux/uio.h @@ -0,0 +1,56 @@ +#ifndef __LINUX_UIO_H +#define __LINUX_UIO_H + +#include <linux/compiler.h> +#include <linux/types.h> + +/* + * Berkeley style UIO structures - Alan Cox 1994. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +struct iovec +{ + void __user *iov_base; /* BSD uses caddr_t (1003.1g requires void *) */ + __kernel_size_t iov_len; /* Must be size_t (1003.1g) */ +}; + +/* + * UIO_MAXIOV shall be at least 16 1003.1g (5.4.1.1) + */ + +#define UIO_FASTIOV 8 +#define UIO_MAXIOV 1024 + +#ifdef __KERNEL__ + +struct kvec { + void *iov_base; /* and that should *never* hold a userland pointer */ + size_t iov_len; +}; + +/* + * Total number of bytes covered by an iovec. + * + * NOTE that it is not safe to use this function until all the iovec's + * segment lengths have been validated. Because the individual lengths can + * overflow a size_t when added together. + */ +static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs) +{ + unsigned long seg; + size_t ret = 0; + + for (seg = 0; seg < nr_segs; seg++) + ret += iov[seg].iov_len; + return ret; +} + +unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to); +#endif + +#endif |