读写控制不叫，如果CMD = 2 [英] ioctl is not called if cmd = 2

问题描述

我开发使用unlocked_ioctl一个内核模块。我用的内核版本2.6.24-23泛型测试，它完美的作品。现在我与内核版本3.3.1-1-ARCH尝试过了，奇怪的事情发生了：当请求值（CMD）为2，返回0，不执行ioctl函数，但不会执行该功能。为了检查它不执行我做了以下内容：

I am developing a kernel module that uses unlocked_ioctl. I tested it with kernel version 2.6.24-23-generic and it works perfectly. Now I tried it with kernel version 3.3.1-1-ARCH and something weird happens: the ioctl function is not executed when the request value (cmd) is 2. It returns 0, but the function is not executed. In order to check that it is not executed I did the following:

static long midriver_ioctl(struct file *file,
    unsigned int cmd, unsigned long arg) {

printk("Called with cmd = %d\n", cmd);

我写了这个设备调用的ioctl从0到4096的测试程序，我可以在dmesg用CMD叫= N的消息对所有这些值看，除了2时，只有一个是未示出。

I wrote a test program that calls ioctl for this device from 0 to 4096, and I can see in dmesg the message "Called with cmd = n" for all those values, except of "2", the only one that is not shown.

什么我做错了任何线索？

Any clues about what I am doing wrong?

感谢你在前进，

推荐答案

上拿的这个：

 546 int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
 547             unsigned long arg)
 548 {
 549        int error = 0;
 550        int __user *argp = (int __user *)arg;
 551        struct inode *inode = filp->f_path.dentry->d_inode;
 552
 553        switch (cmd) {
 554        case FIOCLEX:
 555                set_close_on_exec(fd, 1);
 556                break;
 557
 558        case FIONCLEX:
 559                set_close_on_exec(fd, 0);
 560                break;
 561
 562        case FIONBIO:
 563                error = ioctl_fionbio(filp, argp);
 564                break;
 565
 566        case FIOASYNC:
 567                error = ioctl_fioasync(fd, filp, argp);
 568                break;
 569
 570        case FIOQSIZE:
 571                if (S_ISDIR(inode->i_mode) || S_ISREG(inode->i_mode) ||
 572                    S_ISLNK(inode->i_mode)) {
 573                        loff_t res = inode_get_bytes(inode);
 574                        error = copy_to_user(argp, &res, sizeof(res)) ?
 575                                        -EFAULT : 0;
 576                } else
 577                        error = -ENOTTY;
 578                break;
 579
 580        case FIFREEZE:
 581                error = ioctl_fsfreeze(filp);
 582                break;
 583
 584        case FITHAW:
 585                error = ioctl_fsthaw(filp);
 586                break;
 587
 588        case FS_IOC_FIEMAP:
 589                return ioctl_fiemap(filp, arg);
 590
 591        case FIGETBSZ:
 592                return put_user(inode->i_sb->s_blocksize, argp);
 593
 594        default:
 595                if (S_ISREG(inode->i_mode))
 596                        error = file_ioctl(filp, cmd, arg);
 597                else
 598                        error = vfs_ioctl(filp, cmd, arg);
 599                break;
 600        }
 601        return error;
 602 

正如你可以看到，有一些开关的情况下才 vfs_ioctl 或 file_ioctl 电话。

这篇关于读写控制不叫，如果CMD = 2的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！