kernel_read【转】

转自：http://blog.csdn.net/echoisland/article/details/7101097http://lxr.oss.org.cn/source/fs/exec.c

798 int kernel_read(struct file *file, loff_t offset,
799                 char *addr, unsigned long count)
800 {
801         mm_segment_t old_fs;
802         loff_t pos = offset;
803         int result;
804
805         old_fs = get_fs();
806         set_fs(get_ds());
807         /* The cast to a user pointer is valid due to the set_fs() */
808         result = vfs_read(file, (void __user *)addr, count, &pos);
809         set_fs(old_fs);
810         return result;
811 }
812
813 EXPORT_SYMBOL(kernel_read);