FreeBSD/Linux Kernel Cross Reference
sys/compat/linuxkpi/common/include/linux/refcount.h

     /*-
      * Copyright (c) 2020 The FreeBSD Foundation
      *
      * This software was developed by Emmanuel Vadot under sponsorship
      * from the FreeBSD Foundation.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD$
     */
    
    #ifndef _LINUXKPI_LINUX_REFCOUNT_H
    #define _LINUXKPI_LINUX_REFCOUNT_H
    
    #include <linux/atomic.h>
    
    struct refcount_linux {
            atomic_t value;
    };
    typedef struct refcount_linux refcount_t;
    
    static inline void
    refcount_set(refcount_t *ref, unsigned int i)
    {
            atomic_set(&ref->value, i);
    }
    
    static inline void
    refcount_inc(refcount_t *ref)
    {
            atomic_inc(&ref->value);
    }
    
    static inline bool
    refcount_inc_not_zero(refcount_t *ref)
    {
            return (atomic_inc_not_zero(&ref->value));
    }
    
    static inline void
    refcount_dec(refcount_t *ref)
    {
            atomic_dec(&ref->value);
    }
    
    static inline unsigned int
    refcount_read(refcount_t *ref)
    {
            return atomic_read(&ref->value);
    }
    
    static inline bool
    refcount_dec_and_lock_irqsave(refcount_t *ref, spinlock_t *lock,
        unsigned long *flags)
    {
            if (atomic_dec_and_test(&ref->value) == true) {
                    spin_lock_irqsave(lock, flags);
                    return (true);
            }
            return (false);
    }
    
    /*
     * struct kref uses atomic_t and not refcount_t so
     * we differ from Linux here.
     */
    static inline bool
    refcount_dec_and_test(atomic_t *r)
    {
    
            return (atomic_dec_and_test(r));
    }
    
    #endif /* __LINUXKPI_LINUX_REFCOUNT_H__ */

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