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5141861cd5
During my recent work on the rtnl lock deadlock in the IPoIB driver, I saw that even once I fixed the apparent races for a single device, as soon as that device had any children, new races popped up. It turns out that this is because no matter how well we protect against races on a single device, the fact that all devices use the same workqueue, and flush_workqueue() flushes *everything* from that workqueue, we can have one device in the middle of a down and holding the rtnl lock and another totally unrelated device needing to run mcast_restart_task, which wants the rtnl lock and will loop trying to take it unless is sees its own FLAG_ADMIN_UP flag go away. Because the unrelated interface will never see its own ADMIN_UP flag drop, the interface going down will deadlock trying to flush the queue. There are several possible solutions to this problem: Make carrier_on_task and mcast_restart_task try to take the rtnl for some set period of time and if they fail, then bail. This runs the real risk of dropping work on the floor, which can end up being its own separate kind of deadlock. Set some global flag in the driver that says some device is in the middle of going down, letting all tasks know to bail. Again, this can drop work on the floor. I suppose if our own ADMIN_UP flag doesn't go away, then maybe after a few tries on the rtnl lock we can queue our own task back up as a delayed work and return and avoid dropping work on the floor that way. But I'm not 100% convinced that we won't cause other problems. Or the method this patch attempts to use, which is when we bring an interface up, create a workqueue specifically for that interface, so that when we take it back down, we are flushing only those tasks associated with our interface. In addition, keep the global workqueue, but now limit it to only flush tasks. In this way, the flush tasks can always flush the device specific work queues without having deadlock issues. Signed-off-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Roland Dreier <roland@purestorage.com>
318 lines
8.6 KiB
C
318 lines
8.6 KiB
C
/*
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* Copyright (c) 2004, 2005 Topspin Communications. All rights reserved.
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* Copyright (c) 2005 Mellanox Technologies. All rights reserved.
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*
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* This software is available to you under a choice of one of two
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* licenses. You may choose to be licensed under the terms of the GNU
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* General Public License (GPL) Version 2, available from the file
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* COPYING in the main directory of this source tree, or the
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* OpenIB.org BSD license below:
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*
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* Redistribution and use in source and binary forms, with or
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* without modification, are permitted provided that the following
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* conditions are met:
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*
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* - Redistributions of source code must retain the above
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* copyright notice, this list of conditions and the following
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* disclaimer.
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*
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* - Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include <linux/slab.h>
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#include "ipoib.h"
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int ipoib_mcast_attach(struct net_device *dev, u16 mlid, union ib_gid *mgid, int set_qkey)
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{
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struct ipoib_dev_priv *priv = netdev_priv(dev);
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struct ib_qp_attr *qp_attr = NULL;
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int ret;
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u16 pkey_index;
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if (ib_find_pkey(priv->ca, priv->port, priv->pkey, &pkey_index)) {
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clear_bit(IPOIB_PKEY_ASSIGNED, &priv->flags);
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ret = -ENXIO;
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goto out;
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}
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set_bit(IPOIB_PKEY_ASSIGNED, &priv->flags);
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if (set_qkey) {
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ret = -ENOMEM;
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qp_attr = kmalloc(sizeof *qp_attr, GFP_KERNEL);
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if (!qp_attr)
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goto out;
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/* set correct QKey for QP */
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qp_attr->qkey = priv->qkey;
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ret = ib_modify_qp(priv->qp, qp_attr, IB_QP_QKEY);
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if (ret) {
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ipoib_warn(priv, "failed to modify QP, ret = %d\n", ret);
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goto out;
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}
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}
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/* attach QP to multicast group */
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ret = ib_attach_mcast(priv->qp, mgid, mlid);
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if (ret)
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ipoib_warn(priv, "failed to attach to multicast group, ret = %d\n", ret);
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out:
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kfree(qp_attr);
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return ret;
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}
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int ipoib_init_qp(struct net_device *dev)
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{
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struct ipoib_dev_priv *priv = netdev_priv(dev);
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int ret;
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struct ib_qp_attr qp_attr;
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int attr_mask;
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if (!test_bit(IPOIB_PKEY_ASSIGNED, &priv->flags))
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return -1;
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qp_attr.qp_state = IB_QPS_INIT;
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qp_attr.qkey = 0;
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qp_attr.port_num = priv->port;
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qp_attr.pkey_index = priv->pkey_index;
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attr_mask =
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IB_QP_QKEY |
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IB_QP_PORT |
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IB_QP_PKEY_INDEX |
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IB_QP_STATE;
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ret = ib_modify_qp(priv->qp, &qp_attr, attr_mask);
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if (ret) {
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ipoib_warn(priv, "failed to modify QP to init, ret = %d\n", ret);
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goto out_fail;
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}
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qp_attr.qp_state = IB_QPS_RTR;
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/* Can't set this in a INIT->RTR transition */
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attr_mask &= ~IB_QP_PORT;
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ret = ib_modify_qp(priv->qp, &qp_attr, attr_mask);
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if (ret) {
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ipoib_warn(priv, "failed to modify QP to RTR, ret = %d\n", ret);
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goto out_fail;
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}
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qp_attr.qp_state = IB_QPS_RTS;
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qp_attr.sq_psn = 0;
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attr_mask |= IB_QP_SQ_PSN;
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attr_mask &= ~IB_QP_PKEY_INDEX;
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ret = ib_modify_qp(priv->qp, &qp_attr, attr_mask);
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if (ret) {
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ipoib_warn(priv, "failed to modify QP to RTS, ret = %d\n", ret);
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goto out_fail;
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}
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return 0;
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out_fail:
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qp_attr.qp_state = IB_QPS_RESET;
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if (ib_modify_qp(priv->qp, &qp_attr, IB_QP_STATE))
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ipoib_warn(priv, "Failed to modify QP to RESET state\n");
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return ret;
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}
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int ipoib_transport_dev_init(struct net_device *dev, struct ib_device *ca)
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{
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struct ipoib_dev_priv *priv = netdev_priv(dev);
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struct ib_qp_init_attr init_attr = {
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.cap = {
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.max_send_wr = ipoib_sendq_size,
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.max_recv_wr = ipoib_recvq_size,
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.max_send_sge = 1,
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.max_recv_sge = IPOIB_UD_RX_SG
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},
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.sq_sig_type = IB_SIGNAL_ALL_WR,
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.qp_type = IB_QPT_UD
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};
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int ret, size;
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int i;
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/*
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* the various IPoIB tasks assume they will never race against
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* themselves, so always use a single thread workqueue
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*/
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priv->wq = create_singlethread_workqueue("ipoib_wq");
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if (!priv->wq) {
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printk(KERN_WARNING "ipoib: failed to allocate device WQ\n");
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return -ENODEV;
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}
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priv->pd = ib_alloc_pd(priv->ca);
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if (IS_ERR(priv->pd)) {
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printk(KERN_WARNING "%s: failed to allocate PD\n", ca->name);
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goto out_free_wq;
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}
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priv->mr = ib_get_dma_mr(priv->pd, IB_ACCESS_LOCAL_WRITE);
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if (IS_ERR(priv->mr)) {
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printk(KERN_WARNING "%s: ib_get_dma_mr failed\n", ca->name);
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goto out_free_pd;
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}
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size = ipoib_recvq_size + 1;
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ret = ipoib_cm_dev_init(dev);
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if (!ret) {
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size += ipoib_sendq_size;
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if (ipoib_cm_has_srq(dev))
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size += ipoib_recvq_size + 1; /* 1 extra for rx_drain_qp */
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else
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size += ipoib_recvq_size * ipoib_max_conn_qp;
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}
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priv->recv_cq = ib_create_cq(priv->ca, ipoib_ib_completion, NULL, dev, size, 0);
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if (IS_ERR(priv->recv_cq)) {
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printk(KERN_WARNING "%s: failed to create receive CQ\n", ca->name);
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goto out_free_mr;
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}
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priv->send_cq = ib_create_cq(priv->ca, ipoib_send_comp_handler, NULL,
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dev, ipoib_sendq_size, 0);
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if (IS_ERR(priv->send_cq)) {
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printk(KERN_WARNING "%s: failed to create send CQ\n", ca->name);
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goto out_free_recv_cq;
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}
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if (ib_req_notify_cq(priv->recv_cq, IB_CQ_NEXT_COMP))
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goto out_free_send_cq;
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init_attr.send_cq = priv->send_cq;
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init_attr.recv_cq = priv->recv_cq;
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if (priv->hca_caps & IB_DEVICE_UD_TSO)
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init_attr.create_flags |= IB_QP_CREATE_IPOIB_UD_LSO;
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if (priv->hca_caps & IB_DEVICE_BLOCK_MULTICAST_LOOPBACK)
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init_attr.create_flags |= IB_QP_CREATE_BLOCK_MULTICAST_LOOPBACK;
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if (priv->hca_caps & IB_DEVICE_MANAGED_FLOW_STEERING)
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init_attr.create_flags |= IB_QP_CREATE_NETIF_QP;
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if (dev->features & NETIF_F_SG)
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init_attr.cap.max_send_sge = MAX_SKB_FRAGS + 1;
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priv->qp = ib_create_qp(priv->pd, &init_attr);
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if (IS_ERR(priv->qp)) {
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printk(KERN_WARNING "%s: failed to create QP\n", ca->name);
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goto out_free_send_cq;
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}
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priv->dev->dev_addr[1] = (priv->qp->qp_num >> 16) & 0xff;
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priv->dev->dev_addr[2] = (priv->qp->qp_num >> 8) & 0xff;
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priv->dev->dev_addr[3] = (priv->qp->qp_num ) & 0xff;
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for (i = 0; i < MAX_SKB_FRAGS + 1; ++i)
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priv->tx_sge[i].lkey = priv->mr->lkey;
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priv->tx_wr.opcode = IB_WR_SEND;
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priv->tx_wr.sg_list = priv->tx_sge;
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priv->tx_wr.send_flags = IB_SEND_SIGNALED;
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priv->rx_sge[0].lkey = priv->mr->lkey;
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if (ipoib_ud_need_sg(priv->max_ib_mtu)) {
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priv->rx_sge[0].length = IPOIB_UD_HEAD_SIZE;
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priv->rx_sge[1].length = PAGE_SIZE;
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priv->rx_sge[1].lkey = priv->mr->lkey;
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priv->rx_wr.num_sge = IPOIB_UD_RX_SG;
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} else {
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priv->rx_sge[0].length = IPOIB_UD_BUF_SIZE(priv->max_ib_mtu);
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priv->rx_wr.num_sge = 1;
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}
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priv->rx_wr.next = NULL;
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priv->rx_wr.sg_list = priv->rx_sge;
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return 0;
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out_free_send_cq:
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ib_destroy_cq(priv->send_cq);
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out_free_recv_cq:
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ib_destroy_cq(priv->recv_cq);
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out_free_mr:
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ib_dereg_mr(priv->mr);
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ipoib_cm_dev_cleanup(dev);
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out_free_pd:
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ib_dealloc_pd(priv->pd);
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out_free_wq:
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destroy_workqueue(priv->wq);
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priv->wq = NULL;
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return -ENODEV;
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}
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void ipoib_transport_dev_cleanup(struct net_device *dev)
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{
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struct ipoib_dev_priv *priv = netdev_priv(dev);
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if (priv->qp) {
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if (ib_destroy_qp(priv->qp))
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ipoib_warn(priv, "ib_qp_destroy failed\n");
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priv->qp = NULL;
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clear_bit(IPOIB_PKEY_ASSIGNED, &priv->flags);
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}
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if (ib_destroy_cq(priv->send_cq))
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ipoib_warn(priv, "ib_cq_destroy (send) failed\n");
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if (ib_destroy_cq(priv->recv_cq))
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ipoib_warn(priv, "ib_cq_destroy (recv) failed\n");
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ipoib_cm_dev_cleanup(dev);
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if (ib_dereg_mr(priv->mr))
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ipoib_warn(priv, "ib_dereg_mr failed\n");
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if (ib_dealloc_pd(priv->pd))
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ipoib_warn(priv, "ib_dealloc_pd failed\n");
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if (priv->wq) {
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flush_workqueue(priv->wq);
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destroy_workqueue(priv->wq);
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priv->wq = NULL;
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}
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}
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void ipoib_event(struct ib_event_handler *handler,
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struct ib_event *record)
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{
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struct ipoib_dev_priv *priv =
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container_of(handler, struct ipoib_dev_priv, event_handler);
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if (record->element.port_num != priv->port)
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return;
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ipoib_dbg(priv, "Event %d on device %s port %d\n", record->event,
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record->device->name, record->element.port_num);
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if (record->event == IB_EVENT_SM_CHANGE ||
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record->event == IB_EVENT_CLIENT_REREGISTER) {
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queue_work(ipoib_workqueue, &priv->flush_light);
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} else if (record->event == IB_EVENT_PORT_ERR ||
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record->event == IB_EVENT_PORT_ACTIVE ||
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record->event == IB_EVENT_LID_CHANGE) {
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queue_work(ipoib_workqueue, &priv->flush_normal);
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} else if (record->event == IB_EVENT_PKEY_CHANGE) {
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queue_work(ipoib_workqueue, &priv->flush_heavy);
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}
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}
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