/*

 * Copyright (c) 2020 Red Hat, Inc.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 * 

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA. 

 *

 * $Id: //eng/vdo-releases/aluminum/src/c++/vdo/kernel/threadRegistry.h#1 $

 */

#ifndef THREAD_REGISTRY_H

#define THREAD_REGISTRY_H 1

#include <linux/list.h>

#include <linux/spinlock.h>

/*

 * We don't expect this set to ever get really large, so a linked list

 * is adequate.

 */

typedef struct threadRegistry {

  struct list_head links;

  rwlock_t         lock;

} ThreadRegistry;

typedef struct registeredThread {

  struct list_head    links;

  const void         *pointer;

  struct task_struct *task;

} RegisteredThread;

/*****************************************************************************/

/**

 * Initialize a registry of threads and associated data pointers.

 *

 * @param  registry  The registry to initialize

 **/

void initializeThreadRegistry(ThreadRegistry *registry);

/**

 * Register the current thread and associate it with a data pointer.

 *

 * This call will log messages if the thread is already registered.

 *

 * @param registry   The thread registry

 * @param newThread  RegisteredThread structure to use for the current thread

 * @param pointer    The value to associated with the current thread

 **/

void registerThread(ThreadRegistry   *registry,

                    RegisteredThread *newThread,

                    const void       *pointer);

/**

 * Remove the registration for the current thread.

 *

 * A message may be logged if the thread was not registered.

 *

 * @param  registry  The thread registry

 **/

void unregisterThread(ThreadRegistry *registry);

/**

 * Fetch a pointer that may have been registered for the current

 * thread. If the thread is not registered, a null pointer is

 * returned.

 *

 * @param  registry  The thread registry

 *

 * @return  the registered pointer, if any, or NULL

 **/

const void *lookupThread(ThreadRegistry *registry);

#endif /* THREAD_REGISTRY_H */