How to use plist.h in the rt-path?

Monica Puig-Pey
2011-07-11T12:09:21Z

Hi there,

As I told in previous posts in this list I'm developing drivers for the
linux-rt kernel version in Ubuntu 10.04, based on 2.6.31 with rt_preempt
patch.

Currently I'm studying how to use priority lists (linux/plist.h) in a
module. I read some pages from the Linux Kernel Development book to
learn how linked list work in the kernel.

I made and easy example, shown below, trying to put three elements, with
their priorities, in a plist_head.

Then, I had two problems:

* First error:

An error is produced when using the MACROs:
- PLIST_HEAD_INIT(head, _lock)
- PLIST_NODE_INIT(node, __prio)

it says :

/home/monica/Escritorio/plists/priolist.c: In function
'init_module':
/home/monica/Escritorio/plists/priolist.c:67: error: expected
expression before '.' token

--> To solve this I used the functions:

- static inline void plist_head_init(struct plist_head *head,
struct spinlock *lock)

- static inline void plist_node_init(struct plist_node *node,
int prio)

But I still have the problem with the MACRO

* Second error, problem using plist_add:

It says:

“WARNING: "plist_add" [/home/monica/Escritorio/plists/priolist.ko]
undefined! ”

I made the module GPL, I don't know what am I doing wrong.

Does anybody have an idea what is happening?

Thanks in advance for any help,

Cheers,

Monica

CODE:

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/ioport.h>
#include <linux/plist.h>
#include <linux/spinlock.h>

MODULE_LICENSE("GPL");

#define pid_miguel 1
#define fichero_miguel 1
#define prio_miguel 10

#define pid_monica 2
#define fichero_monica 1
#define prio_monica 30

#define pid_hector 3
#define fichero_hector 1
#define prio_hector 20

static DEFINE_SPINLOCK(lock);

struct misdatos
{
int pid;
int fichero;
struct plist_node token_del_plist;
};

int init_module(void)
{

struct plist_head mi_lista_de_datos;
//struct spinlock lock;
struct misdatos datos_miguel;
struct misdatos datos_monica;
struct misdatos datos_hector;

struct misdatos *elemento_iterador;

// Inicializo mi lista
//PLIST_HEAD_INIT( mi_lista_de_datos, lock);
plist_head_init( &mi_lista_de_datos, &lock);

// Creo mis datos
datos_miguel.pid = pid_miguel;
datos_miguel.fichero = fichero_miguel;

datos_monica.pid = pid_monica;
datos_monica.fichero = fichero_monica;

datos_hector.pid = pid_hector;
datos_hector.fichero = fichero_hector;

// Inicializamos los nodos CON LA PRIORIDAD
//PLIST_NODE_INIT(datos_miguel.token_del_plist, prio_miguel);
//PLIST_NODE_INIT(datos_monica.token_del_plist, prio_monica);
//PLIST_NODE_INIT(datos_hector.token_del_plist, prio_hector);
plist_node_init(&datos_miguel.token_del_plist, prio_miguel);
plist_node_init(&datos_monica.token_del_plist, prio_monica);
plist_node_init(&datos_hector.token_del_plist, prio_hector);

// Los agnadimos
plist_add(&(datos_miguel.token_del_plist), &mi_lista_de_datos);
plist_add(&(datos_monica.token_del_plist), &mi_lista_de_datos);
plist_add(&(datos_hector.token_del_plist), &mi_lista_de_datos);

plist_for_each_entry(elemento_iterador, &mi_lista_de_datos,
token_del_plist)
{
printk(KERN_INFO "El pid es : %d, con prioridad %d\n",
elemento_iterador->pid, elemento_iterador->token_del_plist.prio);
}
return 0;
}

void cleanup_module(void)
{
printk(KERN_INFO "cleanup_module() called\n");

}