Merge tag 'block-5.11-2021-01-10' of git://git.kernel.dk/linux-block

[linux/fpc-iii.git] / drivers / infiniband / ulp / ipoib / ipoib_ib.c

/*
 * 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 <rdma/ib_cache.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

struct ipoib_ah *ipoib_create_ah(struct net_device *dev,
                                 struct ib_pd *pd, struct rdma_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 = rdma_create_ah(pd, attr, RDMA_CREATE_AH_SLEEPABLE);
        if (IS_ERR(vah)) {
                kfree(ah);
                ah = (struct ipoib_ah *)vah;
        } else {
                ah->ah = vah;
                ipoib_dbg(ipoib_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 = ipoib_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])
{
        ib_dma_unmap_single(priv->ca, mapping[0],
                            IPOIB_UD_BUF_SIZE(priv->max_ib_mtu),
                            DMA_FROM_DEVICE);
}

static int ipoib_ib_post_receive(struct net_device *dev, int id)
{
        struct ipoib_dev_priv *priv = ipoib_priv(dev);
        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, NULL);
        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 = ipoib_priv(dev);
        struct sk_buff *skb;
        int buf_size;
        u64 *mapping;

        buf_size = IPOIB_UD_BUF_SIZE(priv->max_ib_mtu);

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

        /*
         * the IP header will be at IPOIP_HARD_LEN + IB_GRH_BYTES, that is
         * 64 bytes aligned
         */
        skb_reserve(skb, sizeof(struct ipoib_pseudo_header));

        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;

        priv->rx_ring[id].skb = skb;
        return skb;
error:
        dev_kfree_skb_any(skb);
        return NULL;
}

static int ipoib_ib_post_receives(struct net_device *dev)
{
        struct ipoib_dev_priv *priv = ipoib_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 = ipoib_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;
        union ib_gid *sgid;

        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;
        }

        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);

        skb_put(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;

        sgid = &((struct ib_grh *)skb->data)->sgid;

        /*
         * 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) {
                int need_repost = 1;

                if ((wc->wc_flags & IB_WC_GRH) &&
                    sgid->global.interface_id != priv->local_gid.global.interface_id)
                        need_repost = 0;

                if (need_repost) {
                        dev_kfree_skb_any(skb);
                        goto repost;
                }
        }

        skb_pull(skb, IB_GRH_BYTES);

        skb->protocol = ((struct ipoib_header *) skb->data)->proto;
        skb_add_pseudo_hdr(skb);

        ++dev->stats.rx_packets;
        dev->stats.rx_bytes += skb->len;
        if (skb->pkt_type == PACKET_MULTICAST)
                dev->stats.multicast++;

        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->recv_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);
}

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),
                                                 skb_frag_off(frag),
                                                 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;
}

void ipoib_dma_unmap_tx(struct ipoib_dev_priv *priv,
                        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(priv->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(priv->ca, mapping[i + off],
                                  skb_frag_size(frag), DMA_TO_DEVICE);
        }
}

/*
 * As the result of a completion error the QP Can be transferred to SQE states.
 * The function checks if the (send)QP is in SQE state and
 * moves it back to RTS state, that in order to have it functional again.
 */
static void ipoib_qp_state_validate_work(struct work_struct *work)
{
        struct ipoib_qp_state_validate *qp_work =
                container_of(work, struct ipoib_qp_state_validate, work);

        struct ipoib_dev_priv *priv = qp_work->priv;
        struct ib_qp_attr qp_attr;
        struct ib_qp_init_attr query_init_attr;
        int ret;

        ret = ib_query_qp(priv->qp, &qp_attr, IB_QP_STATE, &query_init_attr);
        if (ret) {
                ipoib_warn(priv, "%s: Failed to query QP ret: %d\n",
                           __func__, ret);
                goto free_res;
        }
        pr_info("%s: QP: 0x%x is in state: %d\n",
                __func__, priv->qp->qp_num, qp_attr.qp_state);

        /* currently support only in SQE->RTS transition*/
        if (qp_attr.qp_state == IB_QPS_SQE) {
                qp_attr.qp_state = IB_QPS_RTS;

                ret = ib_modify_qp(priv->qp, &qp_attr, IB_QP_STATE);
                if (ret) {
                        pr_warn("failed(%d) modify QP:0x%x SQE->RTS\n",
                                ret, priv->qp->qp_num);
                        goto free_res;
                }
                pr_info("%s: QP: 0x%x moved from IB_QPS_SQE to IB_QPS_RTS\n",
                        __func__, priv->qp->qp_num);
        } else {
                pr_warn("QP (%d) will stay in state: %d\n",
                        priv->qp->qp_num, qp_attr.qp_state);
        }

free_res:
        kfree(qp_work);
}

static void ipoib_ib_handle_tx_wc(struct net_device *dev, struct ib_wc *wc)
{
        struct ipoib_dev_priv *priv = ipoib_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, tx_req);

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

        dev_kfree_skb_any(tx_req->skb);

        ++priv->tx_tail;
        ++priv->global_tx_tail;

        if (unlikely(netif_queue_stopped(dev) &&
                     ((priv->global_tx_head - priv->global_tx_tail) <=
                      ipoib_sendq_size >> 1) &&
                     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) {
                struct ipoib_qp_state_validate *qp_work;
                ipoib_warn(priv,
                           "failed send event (status=%d, wrid=%d vend_err %#x)\n",
                           wc->status, wr_id, wc->vendor_err);
                qp_work = kzalloc(sizeof(*qp_work), GFP_ATOMIC);
                if (!qp_work)
                        return;

                INIT_WORK(&qp_work->work, ipoib_qp_state_validate_work);
                qp_work->priv = priv;
                queue_work(priv->wq, &qp_work->work);
        }
}

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

        n = ib_poll_cq(priv->send_cq, MAX_SEND_CQE, priv->send_wc);
        for (i = 0; i < n; ++i) {
                wc = priv->send_wc + i;
                if (wc->wr_id & IPOIB_OP_CM)
                        ipoib_cm_handle_tx_wc(priv->dev, priv->send_wc + i);
                else
                        ipoib_ib_handle_tx_wc(priv->dev, priv->send_wc + i);
        }
        return n == MAX_SEND_CQE;
}

int ipoib_rx_poll(struct napi_struct *napi, int budget)
{
        struct ipoib_dev_priv *priv =
                container_of(napi, struct ipoib_dev_priv, recv_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 {
                                pr_warn("%s: Got unexpected wqe id\n", __func__);
                        }
                }

                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;
}

int ipoib_tx_poll(struct napi_struct *napi, int budget)
{
        struct ipoib_dev_priv *priv = container_of(napi, struct ipoib_dev_priv,
                                                   send_napi);
        struct net_device *dev = priv->dev;
        int n, i;
        struct ib_wc *wc;

poll_more:
        n = ib_poll_cq(priv->send_cq, MAX_SEND_CQE, priv->send_wc);

        for (i = 0; i < n; i++) {
                wc = priv->send_wc + i;
                if (wc->wr_id & IPOIB_OP_CM)
                        ipoib_cm_handle_tx_wc(dev, wc);
                else
                        ipoib_ib_handle_tx_wc(dev, wc);
        }

        if (n < budget) {
                napi_complete(napi);
                if (unlikely(ib_req_notify_cq(priv->send_cq, IB_CQ_NEXT_COMP |
                                              IB_CQ_REPORT_MISSED_EVENTS)) &&
                    napi_reschedule(napi))
                        goto poll_more;
        }
        return n < 0 ? 0 : n;
}

void ipoib_ib_rx_completion(struct ib_cq *cq, void *ctx_ptr)
{
        struct ipoib_dev_priv *priv = ctx_ptr;

        napi_schedule(&priv->recv_napi);
}

void ipoib_ib_tx_completion(struct ib_cq *cq, void *ctx_ptr)
{
        struct ipoib_dev_priv *priv = ctx_ptr;

        napi_schedule(&priv->send_napi);
}

static inline int post_send(struct ipoib_dev_priv *priv,
                            unsigned int wr_id,
                            struct ib_ah *address, u32 dqpn,
                            struct ipoib_tx_buf *tx_req,
                            void *head, int hlen)
{
        struct sk_buff *skb = tx_req->skb;

        ipoib_build_sge(priv, tx_req);

        priv->tx_wr.wr.wr_id    = wr_id;
        priv->tx_wr.remote_qpn  = dqpn;
        priv->tx_wr.ah          = address;

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

        return ib_post_send(priv->qp, &priv->tx_wr.wr, NULL);
}

int ipoib_send(struct net_device *dev, struct sk_buff *skb,
               struct ib_ah *address, u32 dqpn)
{
        struct ipoib_dev_priv *priv = ipoib_priv(dev);
        struct ipoib_tx_buf *tx_req;
        int hlen, rc;
        void *phead;
        unsigned int usable_sge = priv->max_send_sge - !!skb_headlen(skb);

        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 -1;
                }
        } 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 -1;
                }
                phead = NULL;
                hlen  = 0;
        }
        if (skb_shinfo(skb)->nr_frags > usable_sge) {
                if (skb_linearize(skb) < 0) {
                        ipoib_warn(priv, "skb could not be linearized\n");
                        ++dev->stats.tx_dropped;
                        ++dev->stats.tx_errors;
                        dev_kfree_skb_any(skb);
                        return -1;
                }
                /* Does skb_linearize return ok without reducing nr_frags? */
                if (skb_shinfo(skb)->nr_frags > usable_sge) {
                        ipoib_warn(priv, "too many frags after skb linearize\n");
                        ++dev->stats.tx_dropped;
                        ++dev->stats.tx_errors;
                        dev_kfree_skb_any(skb);
                        return -1;
                }
        }

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

        /*
         * 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 -1;
        }

        if (skb->ip_summed == CHECKSUM_PARTIAL)
                priv->tx_wr.wr.send_flags |= IB_SEND_IP_CSUM;
        else
                priv->tx_wr.wr.send_flags &= ~IB_SEND_IP_CSUM;
        /* increase the tx_head after send success, but use it for queue state */
        if ((priv->global_tx_head - priv->global_tx_tail) ==
            ipoib_sendq_size - 1) {
                ipoib_dbg(priv, "TX ring full, stopping kernel net queue\n");
                netif_stop_queue(dev);
        }

        skb_orphan(skb);
        skb_dst_drop(skb);

        if (netif_queue_stopped(dev))
                if (ib_req_notify_cq(priv->send_cq, IB_CQ_NEXT_COMP |
                                     IB_CQ_REPORT_MISSED_EVENTS) < 0)
                        ipoib_warn(priv, "request notify on send CQ failed\n");

        rc = post_send(priv, priv->tx_head & (ipoib_sendq_size - 1),
                       address, dqpn, tx_req, phead, hlen);
        if (unlikely(rc)) {
                ipoib_warn(priv, "post_send failed, error %d\n", rc);
                ++dev->stats.tx_errors;
                ipoib_dma_unmap_tx(priv, tx_req);
                dev_kfree_skb_any(skb);
                if (netif_queue_stopped(dev))
                        netif_wake_queue(dev);
                rc = 0;
        } else {
                netif_trans_update(dev);

                rc = priv->tx_head;
                ++priv->tx_head;
                ++priv->global_tx_head;
        }
        return rc;
}

static void ipoib_reap_dead_ahs(struct ipoib_dev_priv *priv)
{
        struct ipoib_ah *ah, *tah;
        unsigned long flags;

        netif_tx_lock_bh(priv->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);
                        rdma_destroy_ah(ah->ah, 0);
                        kfree(ah);
                }

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

        ipoib_reap_dead_ahs(priv);

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

static void ipoib_start_ah_reaper(struct ipoib_dev_priv *priv)
{
        clear_bit(IPOIB_STOP_REAPER, &priv->flags);
        queue_delayed_work(priv->wq, &priv->ah_reap_task,
                           round_jiffies_relative(HZ));
}

static void ipoib_stop_ah_reaper(struct ipoib_dev_priv *priv)
{
        set_bit(IPOIB_STOP_REAPER, &priv->flags);
        cancel_delayed_work(&priv->ah_reap_task);
        /*
         * After ipoib_stop_ah_reaper() we always go through
         * ipoib_reap_dead_ahs() which ensures the work is really stopped and
         * does a final flush out of the dead_ah's list
         */
}

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

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

        return pending;
}

static void check_qp_movement_and_print(struct ipoib_dev_priv *priv,
                                        struct ib_qp *qp,
                                        enum ib_qp_state new_state)
{
        struct ib_qp_attr qp_attr;
        struct ib_qp_init_attr query_init_attr;
        int ret;

        ret = ib_query_qp(qp, &qp_attr, IB_QP_STATE, &query_init_attr);
        if (ret) {
                ipoib_warn(priv, "%s: Failed to query QP\n", __func__);
                return;
        }
        /* print according to the new-state and the previous state.*/
        if (new_state == IB_QPS_ERR && qp_attr.qp_state == IB_QPS_RESET)
                ipoib_dbg(priv, "Failed modify QP, IB_QPS_RESET to IB_QPS_ERR, acceptable\n");
        else
                ipoib_warn(priv, "Failed to modify QP to state: %d from state: %d\n",
                           new_state, qp_attr.qp_state);
}

static void ipoib_napi_enable(struct net_device *dev)
{
        struct ipoib_dev_priv *priv = ipoib_priv(dev);

        napi_enable(&priv->recv_napi);
        napi_enable(&priv->send_napi);
}

static void ipoib_napi_disable(struct net_device *dev)
{
        struct ipoib_dev_priv *priv = ipoib_priv(dev);

        napi_disable(&priv->recv_napi);
        napi_disable(&priv->send_napi);
}

int ipoib_ib_dev_stop_default(struct net_device *dev)
{
        struct ipoib_dev_priv *priv = ipoib_priv(dev);
        struct ib_qp_attr qp_attr;
        unsigned long begin;
        struct ipoib_tx_buf *tx_req;
        int i;

        if (test_bit(IPOIB_FLAG_INITIALIZED, &priv->flags))
                ipoib_napi_disable(dev);

        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))
                check_qp_movement_and_print(priv, priv->qp, IB_QPS_ERR);

        /* 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, tx_req);
                                dev_kfree_skb_any(tx_req->skb);
                                ++priv->tx_tail;
                                ++priv->global_tx_tail;
                        }

                        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);

                usleep_range(1000, 2000);
        }

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

timeout:
        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");

        ib_req_notify_cq(priv->recv_cq, IB_CQ_NEXT_COMP);

        return 0;
}

int ipoib_ib_dev_open_default(struct net_device *dev)
{
        struct ipoib_dev_priv *priv = ipoib_priv(dev);
        int ret;

        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);
                goto out;
        }

        ret = ipoib_cm_dev_open(dev);
        if (ret) {
                ipoib_warn(priv, "ipoib_cm_dev_open returned %d\n", ret);
                goto out;
        }

        if (!test_bit(IPOIB_FLAG_INITIALIZED, &priv->flags))
                ipoib_napi_enable(dev);

        return 0;
out:
        return -1;
}

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

        ipoib_pkey_dev_check_presence(dev);

        if (!test_bit(IPOIB_PKEY_ASSIGNED, &priv->flags)) {
                ipoib_warn(priv, "P_Key 0x%04x is %s\n", priv->pkey,
                           (!(priv->pkey & 0x7fff) ? "Invalid" : "not found"));
                return -1;
        }

        ipoib_start_ah_reaper(priv);
        if (priv->rn_ops->ndo_open(dev)) {
                pr_warn("%s: Failed to open dev\n", dev->name);
                goto dev_stop;
        }

        set_bit(IPOIB_FLAG_INITIALIZED, &priv->flags);

        return 0;

dev_stop:
        ipoib_stop_ah_reaper(priv);
        return -1;
}

void ipoib_ib_dev_stop(struct net_device *dev)
{
        struct ipoib_dev_priv *priv = ipoib_priv(dev);

        priv->rn_ops->ndo_stop(dev);

        clear_bit(IPOIB_FLAG_INITIALIZED, &priv->flags);
        ipoib_stop_ah_reaper(priv);
}

void ipoib_pkey_dev_check_presence(struct net_device *dev)
{
        struct ipoib_dev_priv *priv = ipoib_priv(dev);
        struct rdma_netdev *rn = netdev_priv(dev);

        if (!(priv->pkey & 0x7fff) ||
            ib_find_pkey(priv->ca, priv->port, priv->pkey,
                         &priv->pkey_index)) {
                clear_bit(IPOIB_PKEY_ASSIGNED, &priv->flags);
        } else {
                if (rn->set_id)
                        rn->set_id(dev, priv->pkey_index);
                set_bit(IPOIB_PKEY_ASSIGNED, &priv->flags);
        }
}

void ipoib_ib_dev_up(struct net_device *dev)
{
        struct ipoib_dev_priv *priv = ipoib_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;
        }

        set_bit(IPOIB_FLAG_OPER_UP, &priv->flags);

        ipoib_mcast_start_thread(dev);
}

void ipoib_ib_dev_down(struct net_device *dev)
{
        struct ipoib_dev_priv *priv = ipoib_priv(dev);

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

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

        ipoib_mcast_stop_thread(dev);
        ipoib_mcast_dev_flush(dev);

        ipoib_flush_paths(dev);
}

void ipoib_drain_cq(struct net_device *dev)
{
        struct ipoib_dev_priv *priv = ipoib_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 {
                                pr_warn("%s: Got unexpected wqe id\n", __func__);
                        }
                }
        } while (n == IPOIB_NUM_WC);

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

        local_bh_enable();
}

/*
 * Takes whatever value which is in pkey index 0 and updates priv->pkey
 * returns 0 if the pkey value was changed.
 */
static inline int update_parent_pkey(struct ipoib_dev_priv *priv)
{
        int result;
        u16 prev_pkey;

        prev_pkey = priv->pkey;
        result = ib_query_pkey(priv->ca, priv->port, 0, &priv->pkey);
        if (result) {
                ipoib_warn(priv, "ib_query_pkey port %d failed (ret = %d)\n",
                           priv->port, result);
                return result;
        }

        priv->pkey |= 0x8000;

        if (prev_pkey != priv->pkey) {
                ipoib_dbg(priv, "pkey changed from 0x%x to 0x%x\n",
                          prev_pkey, priv->pkey);
                /*
                 * Update the pkey in the broadcast address, while making sure to set
                 * the full membership bit, so that we join the right broadcast group.
                 */
                priv->dev->broadcast[8] = priv->pkey >> 8;
                priv->dev->broadcast[9] = priv->pkey & 0xff;
                return 0;
        }

        return 1;
}
/*
 * returns 0 if pkey value was found in a different slot.
 */
static inline int update_child_pkey(struct ipoib_dev_priv *priv)
{
        u16 old_index = priv->pkey_index;

        priv->pkey_index = 0;
        ipoib_pkey_dev_check_presence(priv->dev);

        if (test_bit(IPOIB_PKEY_ASSIGNED, &priv->flags) &&
            (old_index == priv->pkey_index))
                return 1;
        return 0;
}

/*
 * returns true if the device address of the ipoib interface has changed and the
 * new address is a valid one (i.e in the gid table), return false otherwise.
 */
static bool ipoib_dev_addr_changed_valid(struct ipoib_dev_priv *priv)
{
        union ib_gid search_gid;
        union ib_gid gid0;
        union ib_gid *netdev_gid;
        int err;
        u16 index;
        u8 port;
        bool ret = false;

        netdev_gid = (union ib_gid *)(priv->dev->dev_addr + 4);
        if (rdma_query_gid(priv->ca, priv->port, 0, &gid0))
                return false;

        netif_addr_lock_bh(priv->dev);

        /* The subnet prefix may have changed, update it now so we won't have
         * to do it later
         */
        priv->local_gid.global.subnet_prefix = gid0.global.subnet_prefix;
        netdev_gid->global.subnet_prefix = gid0.global.subnet_prefix;
        search_gid.global.subnet_prefix = gid0.global.subnet_prefix;

        search_gid.global.interface_id = priv->local_gid.global.interface_id;

        netif_addr_unlock_bh(priv->dev);

        err = ib_find_gid(priv->ca, &search_gid, &port, &index);

        netif_addr_lock_bh(priv->dev);

        if (search_gid.global.interface_id !=
            priv->local_gid.global.interface_id)
                /* There was a change while we were looking up the gid, bail
                 * here and let the next work sort this out
                 */
                goto out;

        /* The next section of code needs some background:
         * Per IB spec the port GUID can't change if the HCA is powered on.
         * port GUID is the basis for GID at index 0 which is the basis for
         * the default device address of a ipoib interface.
         *
         * so it seems the flow should be:
         * if user_changed_dev_addr && gid in gid tbl
         *      set bit dev_addr_set
         *      return true
         * else
         *      return false
         *
         * The issue is that there are devices that don't follow the spec,
         * they change the port GUID when the HCA is powered, so in order
         * not to break userspace applications, We need to check if the
         * user wanted to control the device address and we assume that
         * if he sets the device address back to be based on GID index 0,
         * he no longer wishs to control it.
         *
         * If the user doesn't control the the device address,
         * IPOIB_FLAG_DEV_ADDR_SET is set and ib_find_gid failed it means
         * the port GUID has changed and GID at index 0 has changed
         * so we need to change priv->local_gid and priv->dev->dev_addr
         * to reflect the new GID.
         */
        if (!test_bit(IPOIB_FLAG_DEV_ADDR_SET, &priv->flags)) {
                if (!err && port == priv->port) {
                        set_bit(IPOIB_FLAG_DEV_ADDR_SET, &priv->flags);
                        if (index == 0)
                                clear_bit(IPOIB_FLAG_DEV_ADDR_CTRL,
                                          &priv->flags);
                        else
                                set_bit(IPOIB_FLAG_DEV_ADDR_CTRL, &priv->flags);
                        ret = true;
                } else {
                        ret = false;
                }
        } else {
                if (!err && port == priv->port) {
                        ret = true;
                } else {
                        if (!test_bit(IPOIB_FLAG_DEV_ADDR_CTRL, &priv->flags)) {
                                memcpy(&priv->local_gid, &gid0,
                                       sizeof(priv->local_gid));
                                memcpy(priv->dev->dev_addr + 4, &gid0,
                                       sizeof(priv->local_gid));
                                ret = true;
                        }
                }
        }

out:
        netif_addr_unlock_bh(priv->dev);

        return ret;
}

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

        down_read_nested(&priv->vlan_rwsem, nesting);

        /*
         * 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, nesting + 1);

        up_read(&priv->vlan_rwsem);

        if (!test_bit(IPOIB_FLAG_INITIALIZED, &priv->flags) &&
            level != IPOIB_FLUSH_HEAVY) {
                /* Make sure the dev_addr is set even if not flushing */
                if (level == IPOIB_FLUSH_LIGHT)
                        ipoib_dev_addr_changed_valid(priv);
                ipoib_dbg(priv, "Not flushing - IPOIB_FLAG_INITIALIZED not set.\n");
                return;
        }

        if (!test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags)) {
                /* interface is down. update pkey and leave. */
                if (level == IPOIB_FLUSH_HEAVY) {
                        if (!test_bit(IPOIB_FLAG_SUBINTERFACE, &priv->flags))
                                update_parent_pkey(priv);
                        else
                                update_child_pkey(priv);
                } else if (level == IPOIB_FLUSH_LIGHT)
                        ipoib_dev_addr_changed_valid(priv);
                ipoib_dbg(priv, "Not flushing - IPOIB_FLAG_ADMIN_UP not set.\n");
                return;
        }

        if (level == IPOIB_FLUSH_HEAVY) {
                /* child devices chase their origin pkey value, while non-child
                 * (parent) devices should always takes what present in pkey index 0
                 */
                if (test_bit(IPOIB_FLAG_SUBINTERFACE, &priv->flags)) {
                        result = update_child_pkey(priv);
                        if (result) {
                                /* restart QP only if P_Key index is changed */
                                ipoib_dbg(priv, "Not flushing - P_Key index not changed.\n");
                                return;
                        }

                } else {
                        result = update_parent_pkey(priv);
                        /* restart QP only if P_Key value changed */
                        if (result) {
                                ipoib_dbg(priv, "Not flushing - P_Key value not changed.\n");
                                return;
                        }
                }
        }

        if (level == IPOIB_FLUSH_LIGHT) {
                int oper_up;
                ipoib_mark_paths_invalid(dev);
                /* Set IPoIB operation as down to prevent races between:
                 * the flush flow which leaves MCG and on the fly joins
                 * which can happen during that time. mcast restart task
                 * should deal with join requests we missed.
                 */
                oper_up = test_and_clear_bit(IPOIB_FLAG_OPER_UP, &priv->flags);
                ipoib_mcast_dev_flush(dev);
                if (oper_up)
                        set_bit(IPOIB_FLAG_OPER_UP, &priv->flags);
                ipoib_reap_dead_ahs(priv);
        }

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

        if (level == IPOIB_FLUSH_HEAVY) {
                if (test_bit(IPOIB_FLAG_INITIALIZED, &priv->flags))
                        ipoib_ib_dev_stop(dev);

                if (ipoib_ib_dev_open(dev))
                        return;

                if (netif_queue_stopped(dev))
                        netif_start_queue(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);
                if (ipoib_dev_addr_changed_valid(priv))
                        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, 0);
}

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, 0);
}

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

        rtnl_lock();
        __ipoib_ib_dev_flush(priv, IPOIB_FLUSH_HEAVY, 0);
        rtnl_unlock();
}

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

        ipoib_dbg(priv, "cleaning up ib_dev\n");
        /*
         * We must make sure there are no more (path) completions
         * that may wish to touch priv fields that are no longer valid
         */
        ipoib_flush_paths(dev);

        ipoib_mcast_stop_thread(dev);
        ipoib_mcast_dev_flush(dev);

        /*
         * All of our ah references aren't free until after
         * ipoib_mcast_dev_flush(), ipoib_flush_paths, and
         * the neighbor garbage collection is stopped and reaped.
         * That should all be done now, so make a final ah flush.
         */
        ipoib_reap_dead_ahs(priv);

        clear_bit(IPOIB_PKEY_ASSIGNED, &priv->flags);

        priv->rn_ops->ndo_uninit(dev);

        if (priv->pd) {
                ib_dealloc_pd(priv->pd);
                priv->pd = NULL;
        }
}