make 問題(在kernel 2.6.24-1下編譯)
其中一段錯誤
 4 /mnt/200GB/MyShare2/LDD3/examples/scull/access.c: In function 'scull_u_open':
  5 /mnt/200GB/MyShare2/LDD3/examples/scull/access.c:114: error: dereferencing pointer to incomplete type                                                                                
6 /mnt/200GB/MyShare2/LDD3/examples/scull/access.c: In function 'scull_w_available':          
   7 /mnt/200GB/MyShare2/LDD3/examples/scull/access.c:165: error: dereferencing pointer to incomplete type                                                                                
8 /mnt/200GB/MyShare2/LDD3/examples/scull/access.c:166: error: dereferencing pointer to incomplete                                                                               
 9 /mnt/200GB/MyShare2/LDD3/examples/scull/access.c: In function 'scull_w_open':
 10 /mnt/200GB/MyShare2/LDD3/examples/scull/access.c:179: error: 'TASK_INTERRUPTIBLE' undeclared     (first use in this function) 
 11 /mnt/200GB/MyShare2/LDD3/examples/scull/access.c:179: error: (Each undeclared identifier is      reported only once

 source code:
100 static int scull_u_open(struct inode *inode, struct file *filp)
101 {                                                                                            102         struct scull_dev *dev = &scull_u_device; /* device information */
103         spin_lock(&scull_u_lock);                                                            104         if (scull_u_count &&
105                         (scull_u_owner != current->uid) &&  /* allow user */                 106                         (scull_u_owner != current->euid) && /* allow whoever did su */
107                         !capable(CAP_DAC_OVERRIDE)) { /* still allow root */                 108                 spin_unlock(&scull_u_lock);
109                 return -EBUSY;   /* -EPERM would confuse the user */
110         }                                                                                    111         if (scull_u_count == 0)
112                 scull_u_owner = current->uid; /* grab it */
113                                                                                              114         scull_u_count++;
115         spin_unlock(&scull_u_lock);                                                          116
117 /* then, everything else is copied from the bare scull device */
118
119         if ((filp->f_flags & O_ACCMODE) == O_WRONLY)
120                 scull_trim(dev);
121         filp->private_data = dev;
122         return 0;          /* success */
123 }

請問current這個變數是從何而來的

这里有解答：
http://moto.debian.org.tw/viewtopic.php?t=12771&sid=668bb12897de39cfa6468a8f5dfdff74

current从kernel来，它代表当前运行进程的task_struct