ipoib_ib.c

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/*
 * Copyright (c) 2004, 2005 Topspin Communications.  All rights reserved.
 * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
 * Copyright (c) 2005 Mellanox Technologies. All rights reserved.
 * Copyright (c) 2004, 2005 Voltaire, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - 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.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/delay.h>
#include <linux/moduleparam.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>

#include <linux/ip.h>
#include <linux/tcp.h>

#include "ipoib.h"

#ifdef CONFIG_INFINIBAND_IPOIB_DEBUG_DATA
static int data_debug_level;

module_param(data_debug_level, int, 0644);
MODULE_PARM_DESC(data_debug_level,
         "Enable data path debug tracing if > 0");
#endif

static DEFINE_MUTEX(pkey_mutex);

struct ipoib_ah *ipoib_create_ah(struct net_device *dev,
                 struct ib_pd *pd, struct ib_ah_attr *attr)
{
    struct ipoib_ah *ah;
    struct ib_ah *vah;

    ah = kmalloc(sizeof *ah, GFP_KERNEL);
    if (!ah)
        return ERR_PTR(-ENOMEM);

    ah->dev       = dev;
    ah->last_send = 0;
    kref_init(&ah->ref);

    vah = ib_create_ah(pd, attr);
    if (IS_ERR(vah)) {
        kfree(ah);
        ah = (struct ipoib_ah *)vah;
    } else {
        ah->ah = vah;
        ipoib_dbg(netdev_priv(dev), "Created ah %p\n", ah->ah);
    }

    return ah;
}

void ipoib_free_ah(struct kref *kref)
{
    struct ipoib_ah *ah = container_of(kref, struct ipoib_ah, ref);
    struct ipoib_dev_priv *priv = netdev_priv(ah->dev);

    unsigned long flags;

    spin_lock_irqsave(&priv->lock, flags);
    list_add_tail(&ah->list, &priv->dead_ahs);
    spin_unlock_irqrestore(&priv->lock, flags);
}

static void ipoib_ud_dma_unmap_rx(struct ipoib_dev_priv *priv,
                  u64 mapping[IPOIB_UD_RX_SG])
{
    if (ipoib_ud_need_sg(priv->max_ib_mtu)) {
        ib_dma_unmap_single(priv->ca, mapping[0], IPOIB_UD_HEAD_SIZE,
                    DMA_FROM_DEVICE);
        ib_dma_unmap_page(priv->ca, mapping[1], PAGE_SIZE,
                  DMA_FROM_DEVICE);
    } else
        ib_dma_unmap_single(priv->ca, mapping[0],
                    IPOIB_UD_BUF_SIZE(priv->max_ib_mtu),
                    DMA_FROM_DEVICE);
}

static void ipoib_ud_skb_put_frags(struct ipoib_dev_priv *priv,
                   struct sk_buff *skb,
                   unsigned int length)
{
    if (ipoib_ud_need_sg(priv->max_ib_mtu)) {
        skb_frag_t *frag = &skb_shinfo(skb)->frags[0];
        unsigned int size;
        /*
         * There is only two buffers needed for max_payload = 4K,
         * first buf size is IPOIB_UD_HEAD_SIZE
         */
        skb->tail += IPOIB_UD_HEAD_SIZE;
        skb->len  += length;

        size = length - IPOIB_UD_HEAD_SIZE;

        skb_frag_size_set(frag, size);
        skb->data_len += size;
        skb->truesize += PAGE_SIZE;
    } else
        skb_put(skb, length);

}

static int ipoib_ib_post_receive(struct net_device *dev, int id)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    struct ib_recv_wr *bad_wr;
    int ret;

    priv->rx_wr.wr_id   = id | IPOIB_OP_RECV;
    priv->rx_sge[0].addr = priv->rx_ring[id].mapping[0];
    priv->rx_sge[1].addr = priv->rx_ring[id].mapping[1];


    ret = ib_post_recv(priv->qp, &priv->rx_wr, &bad_wr);
    if (unlikely(ret)) {
        ipoib_warn(priv, "receive failed for buf %d (%d)\n", id, ret);
        ipoib_ud_dma_unmap_rx(priv, priv->rx_ring[id].mapping);
        dev_kfree_skb_any(priv->rx_ring[id].skb);
        priv->rx_ring[id].skb = NULL;
    }

    return ret;
}

static struct sk_buff *ipoib_alloc_rx_skb(struct net_device *dev, int id)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    struct sk_buff *skb;
    int buf_size;
    int tailroom;
    u64 *mapping;

    if (ipoib_ud_need_sg(priv->max_ib_mtu)) {
        buf_size = IPOIB_UD_HEAD_SIZE;
        tailroom = 128; /* reserve some tailroom for IP/TCP headers */
    } else {
        buf_size = IPOIB_UD_BUF_SIZE(priv->max_ib_mtu);
        tailroom = 0;
    }

    skb = dev_alloc_skb(buf_size + tailroom + 4);
    if (unlikely(!skb))
        return NULL;

    /*
     * IB will leave a 40 byte gap for a GRH and IPoIB adds a 4 byte
     * header.  So we need 4 more bytes to get to 48 and align the
     * IP header to a multiple of 16.
     */
    skb_reserve(skb, 4);

    mapping = priv->rx_ring[id].mapping;
    mapping[0] = ib_dma_map_single(priv->ca, skb->data, buf_size,
                       DMA_FROM_DEVICE);
    if (unlikely(ib_dma_mapping_error(priv->ca, mapping[0])))
        goto error;

    if (ipoib_ud_need_sg(priv->max_ib_mtu)) {
        struct page *page = alloc_page(GFP_ATOMIC);
        if (!page)
            goto partial_error;
        skb_fill_page_desc(skb, 0, page, 0, PAGE_SIZE);
        mapping[1] =
            ib_dma_map_page(priv->ca, page,
                    0, PAGE_SIZE, DMA_FROM_DEVICE);
        if (unlikely(ib_dma_mapping_error(priv->ca, mapping[1])))
            goto partial_error;
    }

    priv->rx_ring[id].skb = skb;
    return skb;

partial_error:
    ib_dma_unmap_single(priv->ca, mapping[0], buf_size, DMA_FROM_DEVICE);
error:
    dev_kfree_skb_any(skb);
    return NULL;
}

static int ipoib_ib_post_receives(struct net_device *dev)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    int i;

    for (i = 0; i < ipoib_recvq_size; ++i) {
        if (!ipoib_alloc_rx_skb(dev, i)) {
            ipoib_warn(priv, "failed to allocate receive buffer %d\n", i);
            return -ENOMEM;
        }
        if (ipoib_ib_post_receive(dev, i)) {
            ipoib_warn(priv, "ipoib_ib_post_receive failed for buf %d\n", i);
            return -EIO;
        }
    }

    return 0;
}

static void ipoib_ib_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    unsigned int wr_id = wc->wr_id & ~IPOIB_OP_RECV;
    struct sk_buff *skb;
    u64 mapping[IPOIB_UD_RX_SG];
    union ib_gid *dgid;

    ipoib_dbg_data(priv, "recv completion: id %d, status: %d\n",
               wr_id, wc->status);

    if (unlikely(wr_id >= ipoib_recvq_size)) {
        ipoib_warn(priv, "recv completion event with wrid %d (> %d)\n",
               wr_id, ipoib_recvq_size);
        return;
    }

    skb  = priv->rx_ring[wr_id].skb;

    if (unlikely(wc->status != IB_WC_SUCCESS)) {
        if (wc->status != IB_WC_WR_FLUSH_ERR)
            ipoib_warn(priv, "failed recv event "
                   "(status=%d, wrid=%d vend_err %x)\n",
                   wc->status, wr_id, wc->vendor_err);
        ipoib_ud_dma_unmap_rx(priv, priv->rx_ring[wr_id].mapping);
        dev_kfree_skb_any(skb);
        priv->rx_ring[wr_id].skb = NULL;
        return;
    }

    /*
     * Drop packets that this interface sent, ie multicast packets
     * that the HCA has replicated.
     */
    if (wc->slid == priv->local_lid && wc->src_qp == priv->qp->qp_num)
        goto repost;

    memcpy(mapping, priv->rx_ring[wr_id].mapping,
           IPOIB_UD_RX_SG * sizeof *mapping);

    /*
     * If we can't allocate a new RX buffer, dump
     * this packet and reuse the old buffer.
     */
    if (unlikely(!ipoib_alloc_rx_skb(dev, wr_id))) {
        ++dev->stats.rx_dropped;
        goto repost;
    }

    ipoib_dbg_data(priv, "received %d bytes, SLID 0x%04x\n",
               wc->byte_len, wc->slid);

    ipoib_ud_dma_unmap_rx(priv, mapping);
    ipoib_ud_skb_put_frags(priv, skb, wc->byte_len);

    /* First byte of dgid signals multicast when 0xff */
    dgid = &((struct ib_grh *)skb->data)->dgid;

    if (!(wc->wc_flags & IB_WC_GRH) || dgid->raw[0] != 0xff)
        skb->pkt_type = PACKET_HOST;
    else if (memcmp(dgid, dev->broadcast + 4, sizeof(union ib_gid)) == 0)
        skb->pkt_type = PACKET_BROADCAST;
    else
        skb->pkt_type = PACKET_MULTICAST;

    skb_pull(skb, IB_GRH_BYTES);

    skb->protocol = ((struct ipoib_header *) skb->data)->proto;
    skb_reset_mac_header(skb);
    skb_pull(skb, IPOIB_ENCAP_LEN);

    ++dev->stats.rx_packets;
    dev->stats.rx_bytes += skb->len;

    skb->dev = dev;
    if ((dev->features & NETIF_F_RXCSUM) &&
            likely(wc->wc_flags & IB_WC_IP_CSUM_OK))
        skb->ip_summed = CHECKSUM_UNNECESSARY;

    napi_gro_receive(&priv->napi, skb);

repost:
    if (unlikely(ipoib_ib_post_receive(dev, wr_id)))
        ipoib_warn(priv, "ipoib_ib_post_receive failed "
               "for buf %d\n", wr_id);
}

static int ipoib_dma_map_tx(struct ib_device *ca,
                struct ipoib_tx_buf *tx_req)
{
    struct sk_buff *skb = tx_req->skb;
    u64 *mapping = tx_req->mapping;
    int i;
    int off;

    if (skb_headlen(skb)) {
        mapping[0] = ib_dma_map_single(ca, skb->data, skb_headlen(skb),
                           DMA_TO_DEVICE);
        if (unlikely(ib_dma_mapping_error(ca, mapping[0])))
            return -EIO;

        off = 1;
    } else
        off = 0;

    for (i = 0; i < skb_shinfo(skb)->nr_frags; ++i) {
        const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
        mapping[i + off] = ib_dma_map_page(ca,
                         skb_frag_page(frag),
                         frag->page_offset, skb_frag_size(frag),
                         DMA_TO_DEVICE);
        if (unlikely(ib_dma_mapping_error(ca, mapping[i + off])))
            goto partial_error;
    }
    return 0;

partial_error:
    for (; i > 0; --i) {
        const skb_frag_t *frag = &skb_shinfo(skb)->frags[i - 1];

        ib_dma_unmap_page(ca, mapping[i - !off], skb_frag_size(frag), DMA_TO_DEVICE);
    }

    if (off)
        ib_dma_unmap_single(ca, mapping[0], skb_headlen(skb), DMA_TO_DEVICE);

    return -EIO;
}

static void ipoib_dma_unmap_tx(struct ib_device *ca,
                   struct ipoib_tx_buf *tx_req)
{
    struct sk_buff *skb = tx_req->skb;
    u64 *mapping = tx_req->mapping;
    int i;
    int off;

    if (skb_headlen(skb)) {
        ib_dma_unmap_single(ca, mapping[0], skb_headlen(skb), DMA_TO_DEVICE);
        off = 1;
    } else
        off = 0;

    for (i = 0; i < skb_shinfo(skb)->nr_frags; ++i) {
        const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];

        ib_dma_unmap_page(ca, mapping[i + off], skb_frag_size(frag),
                  DMA_TO_DEVICE);
    }
}

static void ipoib_ib_handle_tx_wc(struct net_device *dev, struct ib_wc *wc)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    unsigned int wr_id = wc->wr_id;
    struct ipoib_tx_buf *tx_req;

    ipoib_dbg_data(priv, "send completion: id %d, status: %d\n",
               wr_id, wc->status);

    if (unlikely(wr_id >= ipoib_sendq_size)) {
        ipoib_warn(priv, "send completion event with wrid %d (> %d)\n",
               wr_id, ipoib_sendq_size);
        return;
    }

    tx_req = &priv->tx_ring[wr_id];

    ipoib_dma_unmap_tx(priv->ca, tx_req);

    ++dev->stats.tx_packets;
    dev->stats.tx_bytes += tx_req->skb->len;

    dev_kfree_skb_any(tx_req->skb);

    ++priv->tx_tail;
    if (unlikely(--priv->tx_outstanding == ipoib_sendq_size >> 1) &&
        netif_queue_stopped(dev) &&
        test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))
        netif_wake_queue(dev);

    if (wc->status != IB_WC_SUCCESS &&
        wc->status != IB_WC_WR_FLUSH_ERR)
        ipoib_warn(priv, "failed send event "
               "(status=%d, wrid=%d vend_err %x)\n",
               wc->status, wr_id, wc->vendor_err);
}

static int poll_tx(struct ipoib_dev_priv *priv)
{
    int n, i;

    n = ib_poll_cq(priv->send_cq, MAX_SEND_CQE, priv->send_wc);
    for (i = 0; i < n; ++i)
        ipoib_ib_handle_tx_wc(priv->dev, priv->send_wc + i);

    return n == MAX_SEND_CQE;
}

int ipoib_poll(struct napi_struct *napi, int budget)
{
    struct ipoib_dev_priv *priv = container_of(napi, struct ipoib_dev_priv, napi);
    struct net_device *dev = priv->dev;
    int done;
    int t;
    int n, i;

    done  = 0;

poll_more:
    while (done < budget) {
        int max = (budget - done);

        t = min(IPOIB_NUM_WC, max);
        n = ib_poll_cq(priv->recv_cq, t, priv->ibwc);

        for (i = 0; i < n; i++) {
            struct ib_wc *wc = priv->ibwc + i;

            if (wc->wr_id & IPOIB_OP_RECV) {
                ++done;
                if (wc->wr_id & IPOIB_OP_CM)
                    ipoib_cm_handle_rx_wc(dev, wc);
                else
                    ipoib_ib_handle_rx_wc(dev, wc);
            } else
                ipoib_cm_handle_tx_wc(priv->dev, wc);
        }

        if (n != t)
            break;
    }

    if (done < budget) {
        napi_complete(napi);
        if (unlikely(ib_req_notify_cq(priv->recv_cq,
                          IB_CQ_NEXT_COMP |
                          IB_CQ_REPORT_MISSED_EVENTS)) &&
            napi_reschedule(napi))
            goto poll_more;
    }

    return done;
}

void ipoib_ib_completion(struct ib_cq *cq, void *dev_ptr)
{
    struct net_device *dev = dev_ptr;
    struct ipoib_dev_priv *priv = netdev_priv(dev);

    napi_schedule(&priv->napi);
}

static void drain_tx_cq(struct net_device *dev)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);

    netif_tx_lock(dev);
    while (poll_tx(priv))
        ; /* nothing */

    if (netif_queue_stopped(dev))
        mod_timer(&priv->poll_timer, jiffies + 1);

    netif_tx_unlock(dev);
}

void ipoib_send_comp_handler(struct ib_cq *cq, void *dev_ptr)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev_ptr);

    mod_timer(&priv->poll_timer, jiffies);
}

static inline int post_send(struct ipoib_dev_priv *priv,
                unsigned int wr_id,
                struct ib_ah *address, u32 qpn,
                struct ipoib_tx_buf *tx_req,
                void *head, int hlen)
{
    struct ib_send_wr *bad_wr;
    int i, off;
    struct sk_buff *skb = tx_req->skb;
    skb_frag_t *frags = skb_shinfo(skb)->frags;
    int nr_frags = skb_shinfo(skb)->nr_frags;
    u64 *mapping = tx_req->mapping;

    if (skb_headlen(skb)) {
        priv->tx_sge[0].addr         = mapping[0];
        priv->tx_sge[0].length       = skb_headlen(skb);
        off = 1;
    } else
        off = 0;

    for (i = 0; i < nr_frags; ++i) {
        priv->tx_sge[i + off].addr = mapping[i + off];
        priv->tx_sge[i + off].length = skb_frag_size(&frags[i]);
    }
    priv->tx_wr.num_sge      = nr_frags + off;
    priv->tx_wr.wr_id        = wr_id;
    priv->tx_wr.wr.ud.remote_qpn = qpn;
    priv->tx_wr.wr.ud.ah         = address;

    if (head) {
        priv->tx_wr.wr.ud.mss    = skb_shinfo(skb)->gso_size;
        priv->tx_wr.wr.ud.header = head;
        priv->tx_wr.wr.ud.hlen   = hlen;
        priv->tx_wr.opcode   = IB_WR_LSO;
    } else
        priv->tx_wr.opcode   = IB_WR_SEND;

    return ib_post_send(priv->qp, &priv->tx_wr, &bad_wr);
}

void ipoib_send(struct net_device *dev, struct sk_buff *skb,
        struct ipoib_ah *address, u32 qpn)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    struct ipoib_tx_buf *tx_req;
    int hlen, rc;
    void *phead;

    if (skb_is_gso(skb)) {
        hlen = skb_transport_offset(skb) + tcp_hdrlen(skb);
        phead = skb->data;
        if (unlikely(!skb_pull(skb, hlen))) {
            ipoib_warn(priv, "linear data too small\n");
            ++dev->stats.tx_dropped;
            ++dev->stats.tx_errors;
            dev_kfree_skb_any(skb);
            return;
        }
    } else {
        if (unlikely(skb->len > priv->mcast_mtu + IPOIB_ENCAP_LEN)) {
            ipoib_warn(priv, "packet len %d (> %d) too long to send, dropping\n",
                   skb->len, priv->mcast_mtu + IPOIB_ENCAP_LEN);
            ++dev->stats.tx_dropped;
            ++dev->stats.tx_errors;
            ipoib_cm_skb_too_long(dev, skb, priv->mcast_mtu);
            return;
        }
        phead = NULL;
        hlen  = 0;
    }

    ipoib_dbg_data(priv, "sending packet, length=%d address=%p qpn=0x%06x\n",
               skb->len, address, qpn);

    /*
     * We put the skb into the tx_ring _before_ we call post_send()
     * because it's entirely possible that the completion handler will
     * run before we execute anything after the post_send().  That
     * means we have to make sure everything is properly recorded and
     * our state is consistent before we call post_send().
     */
    tx_req = &priv->tx_ring[priv->tx_head & (ipoib_sendq_size - 1)];
    tx_req->skb = skb;
    if (unlikely(ipoib_dma_map_tx(priv->ca, tx_req))) {
        ++dev->stats.tx_errors;
        dev_kfree_skb_any(skb);
        return;
    }

    if (skb->ip_summed == CHECKSUM_PARTIAL)
        priv->tx_wr.send_flags |= IB_SEND_IP_CSUM;
    else
        priv->tx_wr.send_flags &= ~IB_SEND_IP_CSUM;

    if (++priv->tx_outstanding == ipoib_sendq_size) {
        ipoib_dbg(priv, "TX ring full, stopping kernel net queue\n");
        if (ib_req_notify_cq(priv->send_cq, IB_CQ_NEXT_COMP))
            ipoib_warn(priv, "request notify on send CQ failed\n");
        netif_stop_queue(dev);
    }

    rc = post_send(priv, priv->tx_head & (ipoib_sendq_size - 1),
               address->ah, qpn, tx_req, phead, hlen);
    if (unlikely(rc)) {
        ipoib_warn(priv, "post_send failed, error %d\n", rc);
        ++dev->stats.tx_errors;
        --priv->tx_outstanding;
        ipoib_dma_unmap_tx(priv->ca, tx_req);
        dev_kfree_skb_any(skb);
        if (netif_queue_stopped(dev))
            netif_wake_queue(dev);
    } else {
        dev->trans_start = jiffies;

        address->last_send = priv->tx_head;
        ++priv->tx_head;
        skb_orphan(skb);

    }

    if (unlikely(priv->tx_outstanding > MAX_SEND_CQE))
        while (poll_tx(priv))
            ; /* nothing */
}

static void __ipoib_reap_ah(struct net_device *dev)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    struct ipoib_ah *ah, *tah;
    LIST_HEAD(remove_list);
    unsigned long flags;

    netif_tx_lock_bh(dev);
    spin_lock_irqsave(&priv->lock, flags);

    list_for_each_entry_safe(ah, tah, &priv->dead_ahs, list)
        if ((int) priv->tx_tail - (int) ah->last_send >= 0) {
            list_del(&ah->list);
            ib_destroy_ah(ah->ah);
            kfree(ah);
        }

    spin_unlock_irqrestore(&priv->lock, flags);
    netif_tx_unlock_bh(dev);
}

void ipoib_reap_ah(struct work_struct *work)
{
    struct ipoib_dev_priv *priv =
        container_of(work, struct ipoib_dev_priv, ah_reap_task.work);
    struct net_device *dev = priv->dev;

    __ipoib_reap_ah(dev);

    if (!test_bit(IPOIB_STOP_REAPER, &priv->flags))
        queue_delayed_work(ipoib_workqueue, &priv->ah_reap_task,
                   round_jiffies_relative(HZ));
}

static void ipoib_ib_tx_timer_func(unsigned long ctx)
{
    drain_tx_cq((struct net_device *)ctx);
}

int ipoib_ib_dev_open(struct net_device *dev)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    int ret;

    if (ib_find_pkey(priv->ca, priv->port, priv->pkey, &priv->pkey_index)) {
        ipoib_warn(priv, "P_Key 0x%04x not found\n", priv->pkey);
        clear_bit(IPOIB_PKEY_ASSIGNED, &priv->flags);
        return -1;
    }
    set_bit(IPOIB_PKEY_ASSIGNED, &priv->flags);

    ret = ipoib_init_qp(dev);
    if (ret) {
        ipoib_warn(priv, "ipoib_init_qp returned %d\n", ret);
        return -1;
    }

    ret = ipoib_ib_post_receives(dev);
    if (ret) {
        ipoib_warn(priv, "ipoib_ib_post_receives returned %d\n", ret);
        ipoib_ib_dev_stop(dev, 1);
        return -1;
    }

    ret = ipoib_cm_dev_open(dev);
    if (ret) {
        ipoib_warn(priv, "ipoib_cm_dev_open returned %d\n", ret);
        ipoib_ib_dev_stop(dev, 1);
        return -1;
    }

    clear_bit(IPOIB_STOP_REAPER, &priv->flags);
    queue_delayed_work(ipoib_workqueue, &priv->ah_reap_task,
               round_jiffies_relative(HZ));

    if (!test_and_set_bit(IPOIB_FLAG_INITIALIZED, &priv->flags))
        napi_enable(&priv->napi);

    return 0;
}

static void ipoib_pkey_dev_check_presence(struct net_device *dev)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    u16 pkey_index = 0;

    if (ib_find_pkey(priv->ca, priv->port, priv->pkey, &pkey_index))
        clear_bit(IPOIB_PKEY_ASSIGNED, &priv->flags);
    else
        set_bit(IPOIB_PKEY_ASSIGNED, &priv->flags);
}

int ipoib_ib_dev_up(struct net_device *dev)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);

    ipoib_pkey_dev_check_presence(dev);

    if (!test_bit(IPOIB_PKEY_ASSIGNED, &priv->flags)) {
        ipoib_dbg(priv, "PKEY is not assigned.\n");
        return 0;
    }

    set_bit(IPOIB_FLAG_OPER_UP, &priv->flags);

    return ipoib_mcast_start_thread(dev);
}

int ipoib_ib_dev_down(struct net_device *dev, int flush)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);

    ipoib_dbg(priv, "downing ib_dev\n");

    clear_bit(IPOIB_FLAG_OPER_UP, &priv->flags);
    netif_carrier_off(dev);

    /* Shutdown the P_Key thread if still active */
    if (!test_bit(IPOIB_PKEY_ASSIGNED, &priv->flags)) {
        mutex_lock(&pkey_mutex);
        set_bit(IPOIB_PKEY_STOP, &priv->flags);
        cancel_delayed_work(&priv->pkey_poll_task);
        mutex_unlock(&pkey_mutex);
        if (flush)
            flush_workqueue(ipoib_workqueue);
    }

    ipoib_mcast_stop_thread(dev, flush);
    ipoib_mcast_dev_flush(dev);

    ipoib_flush_paths(dev);

    return 0;
}

static int recvs_pending(struct net_device *dev)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    int pending = 0;
    int i;

    for (i = 0; i < ipoib_recvq_size; ++i)
        if (priv->rx_ring[i].skb)
            ++pending;

    return pending;
}

void ipoib_drain_cq(struct net_device *dev)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    int i, n;

    /*
     * We call completion handling routines that expect to be
     * called from the BH-disabled NAPI poll context, so disable
     * BHs here too.
     */
    local_bh_disable();

    do {
        n = ib_poll_cq(priv->recv_cq, IPOIB_NUM_WC, priv->ibwc);
        for (i = 0; i < n; ++i) {
            /*
             * Convert any successful completions to flush
             * errors to avoid passing packets up the
             * stack after bringing the device down.
             */
            if (priv->ibwc[i].status == IB_WC_SUCCESS)
                priv->ibwc[i].status = IB_WC_WR_FLUSH_ERR;

            if (priv->ibwc[i].wr_id & IPOIB_OP_RECV) {
                if (priv->ibwc[i].wr_id & IPOIB_OP_CM)
                    ipoib_cm_handle_rx_wc(dev, priv->ibwc + i);
                else
                    ipoib_ib_handle_rx_wc(dev, priv->ibwc + i);
            } else
                ipoib_cm_handle_tx_wc(dev, priv->ibwc + i);
        }
    } while (n == IPOIB_NUM_WC);

    while (poll_tx(priv))
        ; /* nothing */

    local_bh_enable();
}

int ipoib_ib_dev_stop(struct net_device *dev, int flush)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    struct ib_qp_attr qp_attr;
    unsigned long begin;
    struct ipoib_tx_buf *tx_req;
    int i;

    if (test_and_clear_bit(IPOIB_FLAG_INITIALIZED, &priv->flags))
        napi_disable(&priv->napi);

    ipoib_cm_dev_stop(dev);

    /*
     * Move our QP to the error state and then reinitialize in
     * when all work requests have completed or have been flushed.
     */
    qp_attr.qp_state = IB_QPS_ERR;
    if (ib_modify_qp(priv->qp, &qp_attr, IB_QP_STATE))
        ipoib_warn(priv, "Failed to modify QP to ERROR state\n");

    /* Wait for all sends and receives to complete */
    begin = jiffies;

    while (priv->tx_head != priv->tx_tail || recvs_pending(dev)) {
        if (time_after(jiffies, begin + 5 * HZ)) {
            ipoib_warn(priv, "timing out; %d sends %d receives not completed\n",
                   priv->tx_head - priv->tx_tail, recvs_pending(dev));

            /*
             * assume the HW is wedged and just free up
             * all our pending work requests.
             */
            while ((int) priv->tx_tail - (int) priv->tx_head < 0) {
                tx_req = &priv->tx_ring[priv->tx_tail &
                            (ipoib_sendq_size - 1)];
                ipoib_dma_unmap_tx(priv->ca, tx_req);
                dev_kfree_skb_any(tx_req->skb);
                ++priv->tx_tail;
                --priv->tx_outstanding;
            }

            for (i = 0; i < ipoib_recvq_size; ++i) {
                struct ipoib_rx_buf *rx_req;

                rx_req = &priv->rx_ring[i];
                if (!rx_req->skb)
                    continue;
                ipoib_ud_dma_unmap_rx(priv,
                              priv->rx_ring[i].mapping);
                dev_kfree_skb_any(rx_req->skb);
                rx_req->skb = NULL;
            }

            goto timeout;
        }

        ipoib_drain_cq(dev);

        msleep(1);
    }

    ipoib_dbg(priv, "All sends and receives done.\n");

timeout:
    del_timer_sync(&priv->poll_timer);
    qp_attr.qp_state = IB_QPS_RESET;
    if (ib_modify_qp(priv->qp, &qp_attr, IB_QP_STATE))
        ipoib_warn(priv, "Failed to modify QP to RESET state\n");

    /* Wait for all AHs to be reaped */
    set_bit(IPOIB_STOP_REAPER, &priv->flags);
    cancel_delayed_work(&priv->ah_reap_task);
    if (flush)
        flush_workqueue(ipoib_workqueue);

    begin = jiffies;

    while (!list_empty(&priv->dead_ahs)) {
        __ipoib_reap_ah(dev);

        if (time_after(jiffies, begin + HZ)) {
            ipoib_warn(priv, "timing out; will leak address handles\n");
            break;
        }

        msleep(1);
    }

    ib_req_notify_cq(priv->recv_cq, IB_CQ_NEXT_COMP);

    return 0;
}

int ipoib_ib_dev_init(struct net_device *dev, struct ib_device *ca, int port)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);

    priv->ca = ca;
    priv->port = port;
    priv->qp = NULL;

    if (ipoib_transport_dev_init(dev, ca)) {
        printk(KERN_WARNING "%s: ipoib_transport_dev_init failed\n", ca->name);
        return -ENODEV;
    }

    setup_timer(&priv->poll_timer, ipoib_ib_tx_timer_func,
            (unsigned long) dev);

    if (dev->flags & IFF_UP) {
        if (ipoib_ib_dev_open(dev)) {
            ipoib_transport_dev_cleanup(dev);
            return -ENODEV;
        }
    }

    return 0;
}

static void __ipoib_ib_dev_flush(struct ipoib_dev_priv *priv,
                enum ipoib_flush_level level)
{
    struct ipoib_dev_priv *cpriv;
    struct net_device *dev = priv->dev;
    u16 new_index;

    mutex_lock(&priv->vlan_mutex);

    /*
     * Flush any child interfaces too -- they might be up even if
     * the parent is down.
     */
    list_for_each_entry(cpriv, &priv->child_intfs, list)
        __ipoib_ib_dev_flush(cpriv, level);

    mutex_unlock(&priv->vlan_mutex);

    if (!test_bit(IPOIB_FLAG_INITIALIZED, &priv->flags)) {
        ipoib_dbg(priv, "Not flushing - IPOIB_FLAG_INITIALIZED not set.\n");
        return;
    }

    if (!test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags)) {
        ipoib_dbg(priv, "Not flushing - IPOIB_FLAG_ADMIN_UP not set.\n");
        return;
    }

    if (level == IPOIB_FLUSH_HEAVY) {
        if (ib_find_pkey(priv->ca, priv->port, priv->pkey, &new_index)) {
            clear_bit(IPOIB_PKEY_ASSIGNED, &priv->flags);
            ipoib_ib_dev_down(dev, 0);
            ipoib_ib_dev_stop(dev, 0);
            if (ipoib_pkey_dev_delay_open(dev))
                return;
        }

        /* restart QP only if P_Key index is changed */
        if (test_and_set_bit(IPOIB_PKEY_ASSIGNED, &priv->flags) &&
            new_index == priv->pkey_index) {
            ipoib_dbg(priv, "Not flushing - P_Key index not changed.\n");
            return;
        }
        priv->pkey_index = new_index;
    }

    if (level == IPOIB_FLUSH_LIGHT) {
        ipoib_mark_paths_invalid(dev);
        ipoib_mcast_dev_flush(dev);
    }

    if (level >= IPOIB_FLUSH_NORMAL)
        ipoib_ib_dev_down(dev, 0);

    if (level == IPOIB_FLUSH_HEAVY) {
        ipoib_ib_dev_stop(dev, 0);
        ipoib_ib_dev_open(dev);
    }

    /*
     * The device could have been brought down between the start and when
     * we get here, don't bring it back up if it's not configured up
     */
    if (test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags)) {
        if (level >= IPOIB_FLUSH_NORMAL)
            ipoib_ib_dev_up(dev);
        ipoib_mcast_restart_task(&priv->restart_task);
    }
}

void ipoib_ib_dev_flush_light(struct work_struct *work)
{
    struct ipoib_dev_priv *priv =
        container_of(work, struct ipoib_dev_priv, flush_light);

    __ipoib_ib_dev_flush(priv, IPOIB_FLUSH_LIGHT);
}

void ipoib_ib_dev_flush_normal(struct work_struct *work)
{
    struct ipoib_dev_priv *priv =
        container_of(work, struct ipoib_dev_priv, flush_normal);

    __ipoib_ib_dev_flush(priv, IPOIB_FLUSH_NORMAL);
}

void ipoib_ib_dev_flush_heavy(struct work_struct *work)
{
    struct ipoib_dev_priv *priv =
        container_of(work, struct ipoib_dev_priv, flush_heavy);

    __ipoib_ib_dev_flush(priv, IPOIB_FLUSH_HEAVY);
}

void ipoib_ib_dev_cleanup(struct net_device *dev)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);

    ipoib_dbg(priv, "cleaning up ib_dev\n");

    ipoib_mcast_stop_thread(dev, 1);
    ipoib_mcast_dev_flush(dev);

    ipoib_transport_dev_cleanup(dev);
}

/*
 * Delayed P_Key Assigment Interim Support
 *
 * The following is initial implementation of delayed P_Key assigment
 * mechanism. It is using the same approach implemented for the multicast
 * group join. The single goal of this implementation is to quickly address
 * Bug #2507. This implementation will probably be removed when the P_Key
 * change async notification is available.
 */

void ipoib_pkey_poll(struct work_struct *work)
{
    struct ipoib_dev_priv *priv =
        container_of(work, struct ipoib_dev_priv, pkey_poll_task.work);
    struct net_device *dev = priv->dev;

    ipoib_pkey_dev_check_presence(dev);

    if (test_bit(IPOIB_PKEY_ASSIGNED, &priv->flags))
        ipoib_open(dev);
    else {
        mutex_lock(&pkey_mutex);
        if (!test_bit(IPOIB_PKEY_STOP, &priv->flags))
            queue_delayed_work(ipoib_workqueue,
                       &priv->pkey_poll_task,
                       HZ);
        mutex_unlock(&pkey_mutex);
    }
}

int ipoib_pkey_dev_delay_open(struct net_device *dev)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);

    /* Look for the interface pkey value in the IB Port P_Key table and */
    /* set the interface pkey assigment flag                            */
    ipoib_pkey_dev_check_presence(dev);

    /* P_Key value not assigned yet - start polling */
    if (!test_bit(IPOIB_PKEY_ASSIGNED, &priv->flags)) {
        mutex_lock(&pkey_mutex);
        clear_bit(IPOIB_PKEY_STOP, &priv->flags);
        queue_delayed_work(ipoib_workqueue,
                   &priv->pkey_poll_task,
                   HZ);
        mutex_unlock(&pkey_mutex);
        return 1;
    }

    return 0;
}