Re: em(4) VLAN + PROMISC still doesn't work with latest CVS version

From: Iasen Kostov (tbyte_at_OTEL.net)
Date: 12/08/04

  • Next message: Robert Watson: "Re: em(4) VLAN + PROMISC still doesn't work with latest CVS version" 
    Date: Wed, 08 Dec 2004 12:58:31 +0200
To: Robert Watson <rwatson@freebsd.org>

    Robert Watson wrote:

    >On Tue, 7 Dec 2004, Iasen Kostov wrote:
    >
    >
    >
    >> Is there an update on this case or I should find a way to disable
    >>all hw "things" in the driver ?:) (because things are getting hot here
    >>:).
    >>
    >>
    >
    >Try the attached patch? The vlan header in promisc mode was getting
    >inserted after the mbuf was mapped for dma, so under some circumstances
    >the remainder of the packet but not the header would be sent. Given that
    >the previous change tested fine before, I'm wondering if the recent busdma
    >changes have triggered this bug.
    >
    >I'm beginning to think the right fix here is actually to always leave the
    >hardware turned on and to re-insert the vlan header on receive, not insert
    >on transmit, in order to avoid races for queued packets during state
    >transitions. I'll have a chance to investigate that before going on
    >travel Friday, I hope.
    >
    >
    >
    The patch generates .rej against this version:

    /*$FreeBSD: src/sys/dev/em/if_em.c,v 1.44.2.4 2004/11/23 22:28:40
    rwatson Exp $*/

    ***************
    *** 1273,1292 ****
            m_head = m_pullup(m_head, sizeof(eh));
            if (m_head == NULL) {
                *m_headp = NULL;
    - bus_dmamap_destroy(adapter->txtag, q.map);
                return (ENOBUFS);
            }
            eh = *mtod(m_head, struct ether_header *);
            M_PREPEND(m_head, sizeof(*evl), M_DONTWAIT);
            if (m_head == NULL) {
                *m_headp = NULL;
    - bus_dmamap_destroy(adapter->txtag, q.map);
                return (ENOBUFS);
            }
            m_head = m_pullup(m_head, sizeof(*evl));
            if (m_head == NULL) {
                *m_headp = NULL;
    - bus_dmamap_destroy(adapter->txtag, q.map);
                return (ENOBUFS);
            }
            evl = mtod(m_head, struct ether_vlan_header *);
    --- 1243,1259 ----
            m_head = m_pullup(m_head, sizeof(eh));
            if (m_head == NULL) {
                *m_headp = NULL;
                return (ENOBUFS);
            }
            eh = *mtod(m_head, struct ether_header *);
            M_PREPEND(m_head, sizeof(*evl), M_DONTWAIT);
            if (m_head == NULL) {
                *m_headp = NULL;
                return (ENOBUFS);
            }
            m_head = m_pullup(m_head, sizeof(*evl));
            if (m_head == NULL) {
                *m_headp = NULL;
                return (ENOBUFS);
            }
            evl = mtod(m_head, struct ether_vlan_header *);

    should I use the version from -CURRENT or it is possible (adjusted
    patch) to work with this one ?

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