Question

我需要实施一个Lino Kernel司机,(第一步)只把所有档案业务推向另一个档案(在以后的步骤中,应当加以管理和操纵,但我不想在此讨论这个问题)。

我的想法如下,但在阅读时,油轮坠毁:

static struct {
    struct file *file;
    char *file_name;
    int open;
} file_out_data = {
.file_name  = "/any_file",
.open       = 0, 
};


int memory_open(struct inode *inode, struct file *filp) {
  PRINTK("<1>open memory module
");
    /* 
     * We don t want to talk to two processes at the same time 
     */
    if (file_out_data.open)
        return -EBUSY;
    /*
     * Initialize the message 
     */
    Message_Ptr = Message;
    try_module_get(THIS_MODULE);

        file_out_data.file = filp_open(file_out_data.file_name, filp->f_flags, filp->f_mode); //here should be another return handling in case of fail
    file_out_data.open++;

  /* Success */
  return 0;
}

int memory_release(struct inode *inode, struct file *filp) {
      PRINTK("<1>release memory module
");
    /* 
     * We re now ready for our next caller 
     */
    file_out_data.open--;
    filp_close(file_out_data.file,NULL);

    module_put(THIS_MODULE);
  /* Success */
  return 0;
}

ssize_t memory_read(struct file *filp, char *buf, 
                    size_t count, loff_t *f_pos) { 
   PRINTK("<1>read memory module 
");
ret=file_out_data.file->f_op->read(file_out_data.file,buf,count,f_pos); //corrected one, false one is to find in the history
    return ret;

}

So, can anyone please tell me why?

Answer 1

Don t use set_fs() as there is no reason to do it.
Use file->f_fop->read() instead of the vfs_read. Take a look at the file and file_operations structures.

Answer 2

为什么你将<条码>文件_out_data. open<>/code>两倍加,一劳永逸? 这可能导致你使用<条码>文档_out_data.file。关闭后。

Answer 3

You want to write memory in your file ou read? Because you are reading and not writing... possible i m wrong

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