FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_bufring.c

     /**************************************************************************
      *
      * Copyright (c) 2007,2008 Kip Macy kmacy@freebsd.org
      * All rights reserved.
      *
      * 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. The name of Kip Macy nor the names of other
     *    contributors may be used to endorse or promote products derived from
     *    this software without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
     *
     *
     ***************************************************************************/
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/8.0/sys/kern/subr_bufring.c 185162 2008-11-22 05:55:56Z kmacy $");
    
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #include <sys/ktr.h>
    #include <sys/buf_ring.h>
    
    
    struct buf_ring *
    buf_ring_alloc(int count, struct malloc_type *type, int flags, struct mtx *lock)
    {
            struct buf_ring *br;
    
            KASSERT(powerof2(count), ("buf ring must be size power of 2"));
            
            br = malloc(sizeof(struct buf_ring) + count*sizeof(caddr_t),
                type, flags|M_ZERO);
            if (br == NULL)
                    return (NULL);
    #ifdef DEBUG_BUFRING
            br->br_lock = lock;
    #endif  
            br->br_prod_size = br->br_cons_size = count;
            br->br_prod_mask = br->br_cons_mask = count-1;
            br->br_prod_head = br->br_cons_head = 0;
            br->br_prod_tail = br->br_cons_tail = 0;
                    
            return (br);
    }
    
    void
    buf_ring_free(struct buf_ring *br, struct malloc_type *type)
    {
            free(br, type);
    }

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