如何利用共享内存 实现rpc调用

关于RPC 路由器的实现主要分布在smd_rpcrouterc、smd_rpcrouter_devicec、smd_rpcrouter_serversc、smd_rpcrouter_clientsc等文件中。RPC路由器起着RPC服务器查询、RPC服务器和RPC客户端的注册和销毁，以及底层通信的封装功能，类似于TCP协议。

在实际的实现中，RPC路由器和RPC服务器均是作为一个虚拟的字符型设备来存在的。

下面是RPC路由器的创建过程：

代码3-11 RPC 路由器的创建过程

int msm_rpcrouter_init_devices(void)

{

int rc;

int major;

msm_rpcrouter_class=class_create(THIS_MODULE,

"oncrpc"); //创建设备节点

if (IS_ERR(msm_rpcrouter_class)) {

rc=-ENOMEM;

printk(KERN_ERR

"rpcrouter: failed to create oncrpc class\n");

goto fail;

}

rc=alloc_chrdev_region(&msm_rpcrouter_devno,

0, //作为字符型设备分配资源

RPCROUTER_MAX_REMOTE_SERVERS + 1, "oncrpc");

if (rc<0) {

printk(KERN_ERR

"rpcrouter: Failed to alloc chardev region (%d)\n", rc);

goto fail_destroy_class;

}

major=MAJOR(msm_rpcrouter_devno);

rpcrouter_device=device_create(msm_

rpcrouter_class, NULL, //创建设备

msm_rpcrouter_devno, NULL, "%8x:%d",

0, 0);

if (IS_ERR(rpcrouter_device)) {

rc=-ENOMEM;

goto fail_unregister_cdev_region;

}

cdev_init(&rpcrouter_cdev, &rpcrouter_

router_fops); //字符型设备初始化

rpcrouter_cdevowner=THIS_MODULE;

rc=cdev_add(&rpcrouter_cdev, msm_rpcrouter_devno, 1);

if (rc<0)

goto fail_destroy_device;

return 0;

fail_destroy_device:

device_destroy(msm_rpcrouter_class,

msm_rpcrouter_devno);//销毁设备

fail_unregister_cdev_region:

unregister_chrdev_region(msm_rpcrouter_devno, //去注册

RPCROUTER_MAX_REMOTE_SERVERS + 1);

fail_destroy_class:

class_destroy(msm_rpcrouter_class);

fail:

return rc;

}