uipc_mvec.c

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/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * 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. 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.
 */
 
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
 
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/ktr.h>
 
#include <vm/vm.h>
#include <vm/pmap.h>
 
#include <machine/bus.h>
 
#include <cxgb_include.h>
#include <sys/mvec.h>
 
#ifdef INVARIANTS
#define M_SANITY m_sanity
#else
#define M_SANITY(a, b)
#endif
 
int
busdma_map_sg_collapse(bus_dma_tag_t tag, bus_dmamap_t map,
        struct mbuf **m, bus_dma_segment_t *segs, int *nsegs)
{
        struct mbuf *n = *m;
        int seg_count, defragged = 0, err = 0;
        
        KASSERT(n->m_pkthdr.len, ("packet has zero header len"));
        if (n->m_pkthdr.len <= PIO_LEN)
                return (0);
retry:
        seg_count = 0;
        err = bus_dmamap_load_mbuf_sg(tag, map, *m, segs, &seg_count, 0);
        if (seg_count == 0) {
                if (cxgb_debug)
                        printf("empty segment chain\n");
                err = EFBIG;
                goto err_out;
        }  else if (err == EFBIG || seg_count >= TX_MAX_SEGS) {
                if (cxgb_debug)
                        printf("mbuf chain too long: %d max allowed %d\n",
                            seg_count, TX_MAX_SEGS);
                if (!defragged) {
                        n = m_defrag(*m, M_NOWAIT);
                        if (n == NULL) {
                                err = ENOBUFS;
                                goto err_out;
                        }
                        *m = n;
                        defragged = 1;
                        goto retry;
                }
                err = EFBIG;
                goto err_out;
        }
 
        *nsegs = seg_count;
err_out:        
        return (err);
}
 
void
busdma_map_sg_vec(bus_dma_tag_t tag, bus_dmamap_t map,
    struct mbuf *m, bus_dma_segment_t *segs, int *nsegs)
{
        int n = 0;
 
        for (*nsegs = 0; m != NULL; segs += n, *nsegs += n, m = m->m_nextpkt)
                bus_dmamap_load_mbuf_sg(tag, map, m, segs, &n, 0);
}