linux-imx

// SPDX-License-Identifier: GPL-2.0+

/*

 * Sleepable Read-Copy Update mechanism for mutual exclusion,

 *  tiny version for non-preemptible single-CPU use.

 *

 * Copyright (C) IBM Corporation, 2017

 *

 * Author: Paul McKenney <paulmck@linux.ibm.com>

 */

​

#include <linux/export.h>

#include <linux/mutex.h>

#include <linux/preempt.h>

#include <linux/rcupdate_wait.h>

#include <linux/sched.h>

#include <linux/delay.h>

#include <linux/srcu.h>

​

#include <linux/rcu_node_tree.h>

#include "rcu_segcblist.h"

#include "rcu.h"

​

int rcu_scheduler_active __read_mostly;

static LIST_HEAD(srcu_boot_list);

static bool srcu_init_done;

​

static int init_srcu_struct_fields(struct srcu_struct *ssp)

{

    ssp->srcu_lock_nesting[0] = 0;

    ssp->srcu_lock_nesting[1] = 0;

    init_swait_queue_head(&ssp->srcu_wq);

    ssp->srcu_cb_head = NULL;

    ssp->srcu_cb_tail = &ssp->srcu_cb_head;

    ssp->srcu_gp_running = false;

    ssp->srcu_gp_waiting = false;

    ssp->srcu_idx = 0;

    INIT_WORK(&ssp->srcu_work, srcu_drive_gp);

    INIT_LIST_HEAD(&ssp->srcu_work.entry);

    return 0;

}

​

#ifdef CONFIG_DEBUG_LOCK_ALLOC

​

int __init_srcu_struct(struct srcu_struct *ssp, const char *name,

               struct lock_class_key *key)

{

    /* Don't re-initialize a lock while it is held. */

    debug_check_no_locks_freed((void *)ssp, sizeof(*ssp));

    lockdep_init_map(&ssp->dep_map, name, key, 0);

    return init_srcu_struct_fields(ssp);

}

EXPORT_SYMBOL_GPL(__init_srcu_struct);

​

#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */

​

/*

 * init_srcu_struct - initialize a sleep-RCU structure

 * @ssp: structure to initialize.

 *

 * Must invoke this on a given srcu_struct before passing that srcu_struct

 * to any other function.  Each srcu_struct represents a separate domain

 * of SRCU protection.

 */

int init_srcu_struct(struct srcu_struct *ssp)

{

    return init_srcu_struct_fields(ssp);

}

EXPORT_SYMBOL_GPL(init_srcu_struct);

​

#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */

​

/*

 * cleanup_srcu_struct - deconstruct a sleep-RCU structure

 * @ssp: structure to clean up.

 *

 * Must invoke this after you are finished using a given srcu_struct that

 * was initialized via init_srcu_struct(), else you leak memory.

 */

void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced)

{

    WARN_ON(ssp->srcu_lock_nesting[0] || ssp->srcu_lock_nesting[1]);

    if (quiesced)

        WARN_ON(work_pending(&ssp->srcu_work));

    else

        flush_work(&ssp->srcu_work);

    WARN_ON(ssp->srcu_gp_running);

    WARN_ON(ssp->srcu_gp_waiting);

    WARN_ON(ssp->srcu_cb_head);

    WARN_ON(&ssp->srcu_cb_head != ssp->srcu_cb_tail);

}

EXPORT_SYMBOL_GPL(_cleanup_srcu_struct);

​