cm.c

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/*
 * Copyright (c) 2012 Mellanox Technologies. 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 <rdma/ib_mad.h>

#include <linux/mlx4/cmd.h>
#include <linux/rbtree.h>
#include <linux/idr.h>
#include <rdma/ib_cm.h>

#include "mlx4_ib.h"

#define CM_CLEANUP_CACHE_TIMEOUT  (5 * HZ)

struct id_map_entry {
    struct rb_node node;

    u32 sl_cm_id;
    u32 pv_cm_id;
    int slave_id;
    int scheduled_delete;
    struct mlx4_ib_dev *dev;

    struct list_head list;
    struct delayed_work timeout;
};

struct cm_generic_msg {
    struct ib_mad_hdr hdr;

    __be32 local_comm_id;
    __be32 remote_comm_id;
};

struct cm_req_msg {
    unsigned char unused[0x60];
    union ib_gid primary_path_sgid;
};


static void set_local_comm_id(struct ib_mad *mad, u32 cm_id)
{
    struct cm_generic_msg *msg = (struct cm_generic_msg *)mad;
    msg->local_comm_id = cpu_to_be32(cm_id);
}

static u32 get_local_comm_id(struct ib_mad *mad)
{
    struct cm_generic_msg *msg = (struct cm_generic_msg *)mad;

    return be32_to_cpu(msg->local_comm_id);
}

static void set_remote_comm_id(struct ib_mad *mad, u32 cm_id)
{
    struct cm_generic_msg *msg = (struct cm_generic_msg *)mad;
    msg->remote_comm_id = cpu_to_be32(cm_id);
}

static u32 get_remote_comm_id(struct ib_mad *mad)
{
    struct cm_generic_msg *msg = (struct cm_generic_msg *)mad;

    return be32_to_cpu(msg->remote_comm_id);
}

static union ib_gid gid_from_req_msg(struct ib_device *ibdev, struct ib_mad *mad)
{
    struct cm_req_msg *msg = (struct cm_req_msg *)mad;

    return msg->primary_path_sgid;
}

/* Lock should be taken before called */
static struct id_map_entry *
id_map_find_by_sl_id(struct ib_device *ibdev, u32 slave_id, u32 sl_cm_id)
{
    struct rb_root *sl_id_map = &to_mdev(ibdev)->sriov.sl_id_map;
    struct rb_node *node = sl_id_map->rb_node;

    while (node) {
        struct id_map_entry *id_map_entry =
            rb_entry(node, struct id_map_entry, node);

        if (id_map_entry->sl_cm_id > sl_cm_id)
            node = node->rb_left;
        else if (id_map_entry->sl_cm_id < sl_cm_id)
            node = node->rb_right;
        else if (id_map_entry->slave_id > slave_id)
            node = node->rb_left;
        else if (id_map_entry->slave_id < slave_id)
            node = node->rb_right;
        else
            return id_map_entry;
    }
    return NULL;
}

static void id_map_ent_timeout(struct work_struct *work)
{
    struct delayed_work *delay = to_delayed_work(work);
    struct id_map_entry *ent = container_of(delay, struct id_map_entry, timeout);
    struct id_map_entry *db_ent, *found_ent;
    struct mlx4_ib_dev *dev = ent->dev;
    struct mlx4_ib_sriov *sriov = &dev->sriov;
    struct rb_root *sl_id_map = &sriov->sl_id_map;
    int pv_id = (int) ent->pv_cm_id;

    spin_lock(&sriov->id_map_lock);
    db_ent = (struct id_map_entry *)idr_find(&sriov->pv_id_table, pv_id);
    if (!db_ent)
        goto out;
    found_ent = id_map_find_by_sl_id(&dev->ib_dev, ent->slave_id, ent->sl_cm_id);
    if (found_ent && found_ent == ent)
        rb_erase(&found_ent->node, sl_id_map);
    idr_remove(&sriov->pv_id_table, pv_id);

out:
    list_del(&ent->list);
    spin_unlock(&sriov->id_map_lock);
    kfree(ent);
}

static void id_map_find_del(struct ib_device *ibdev, int pv_cm_id)
{
    struct mlx4_ib_sriov *sriov = &to_mdev(ibdev)->sriov;
    struct rb_root *sl_id_map = &sriov->sl_id_map;
    struct id_map_entry *ent, *found_ent;

    spin_lock(&sriov->id_map_lock);
    ent = (struct id_map_entry *)idr_find(&sriov->pv_id_table, pv_cm_id);
    if (!ent)
        goto out;
    found_ent = id_map_find_by_sl_id(ibdev, ent->slave_id, ent->sl_cm_id);
    if (found_ent && found_ent == ent)
        rb_erase(&found_ent->node, sl_id_map);
    idr_remove(&sriov->pv_id_table, pv_cm_id);
out:
    spin_unlock(&sriov->id_map_lock);
}

static void sl_id_map_add(struct ib_device *ibdev, struct id_map_entry *new)
{
    struct rb_root *sl_id_map = &to_mdev(ibdev)->sriov.sl_id_map;
    struct rb_node **link = &sl_id_map->rb_node, *parent = NULL;
    struct id_map_entry *ent;
    int slave_id = new->slave_id;
    int sl_cm_id = new->sl_cm_id;

    ent = id_map_find_by_sl_id(ibdev, slave_id, sl_cm_id);
    if (ent) {
        pr_debug("overriding existing sl_id_map entry (cm_id = %x)\n",
             sl_cm_id);

        rb_replace_node(&ent->node, &new->node, sl_id_map);
        return;
    }

    /* Go to the bottom of the tree */
    while (*link) {
        parent = *link;
        ent = rb_entry(parent, struct id_map_entry, node);

        if (ent->sl_cm_id > sl_cm_id || (ent->sl_cm_id == sl_cm_id && ent->slave_id > slave_id))
            link = &(*link)->rb_left;
        else
            link = &(*link)->rb_right;
    }

    rb_link_node(&new->node, parent, link);
    rb_insert_color(&new->node, sl_id_map);
}

static struct id_map_entry *
id_map_alloc(struct ib_device *ibdev, int slave_id, u32 sl_cm_id)
{
    int ret, id;
    static int next_id;
    struct id_map_entry *ent;
    struct mlx4_ib_sriov *sriov = &to_mdev(ibdev)->sriov;

    ent = kmalloc(sizeof (struct id_map_entry), GFP_KERNEL);
    if (!ent) {
        mlx4_ib_warn(ibdev, "Couldn't allocate id cache entry - out of memory\n");
        return ERR_PTR(-ENOMEM);
    }

    ent->sl_cm_id = sl_cm_id;
    ent->slave_id = slave_id;
    ent->scheduled_delete = 0;
    ent->dev = to_mdev(ibdev);
    INIT_DELAYED_WORK(&ent->timeout, id_map_ent_timeout);

    do {
        spin_lock(&to_mdev(ibdev)->sriov.id_map_lock);
        ret = idr_get_new_above(&sriov->pv_id_table, ent,
                    next_id, &id);
        if (!ret) {
            next_id = ((unsigned) id + 1) & MAX_IDR_MASK;
            ent->pv_cm_id = (u32)id;
            sl_id_map_add(ibdev, ent);
        }

        spin_unlock(&sriov->id_map_lock);
    } while (ret == -EAGAIN && idr_pre_get(&sriov->pv_id_table, GFP_KERNEL));
    /*the function idr_get_new_above can return -ENOSPC, so don't insert in that case.*/
    if (!ret) {
        spin_lock(&sriov->id_map_lock);
        list_add_tail(&ent->list, &sriov->cm_list);
        spin_unlock(&sriov->id_map_lock);
        return ent;
    }
    /*error flow*/
    kfree(ent);
    mlx4_ib_warn(ibdev, "No more space in the idr (err:0x%x)\n", ret);
    return ERR_PTR(-ENOMEM);
}

static struct id_map_entry *
id_map_get(struct ib_device *ibdev, int *pv_cm_id, int sl_cm_id, int slave_id)
{
    struct id_map_entry *ent;
    struct mlx4_ib_sriov *sriov = &to_mdev(ibdev)->sriov;

    spin_lock(&sriov->id_map_lock);
    if (*pv_cm_id == -1) {
        ent = id_map_find_by_sl_id(ibdev, sl_cm_id, slave_id);
        if (ent)
            *pv_cm_id = (int) ent->pv_cm_id;
    } else
        ent = (struct id_map_entry *)idr_find(&sriov->pv_id_table, *pv_cm_id);
    spin_unlock(&sriov->id_map_lock);

    return ent;
}

static void schedule_delayed(struct ib_device *ibdev, struct id_map_entry *id)
{
    struct mlx4_ib_sriov *sriov = &to_mdev(ibdev)->sriov;
    unsigned long flags;

    spin_lock_irqsave(&sriov->going_down_lock, flags);
    spin_lock(&sriov->id_map_lock);
    /*make sure that there is no schedule inside the scheduled work.*/
    if (!sriov->is_going_down) {
        id->scheduled_delete = 1;
        schedule_delayed_work(&id->timeout, CM_CLEANUP_CACHE_TIMEOUT);
    }
    spin_unlock(&sriov->id_map_lock);
    spin_unlock_irqrestore(&sriov->going_down_lock, flags);
}

int mlx4_ib_multiplex_cm_handler(struct ib_device *ibdev, int port, int slave_id,
        struct ib_mad *mad)
{
    struct id_map_entry *id;
    u32 sl_cm_id;
    int pv_cm_id = -1;

    sl_cm_id = get_local_comm_id(mad);

    if (mad->mad_hdr.attr_id == CM_REQ_ATTR_ID ||
            mad->mad_hdr.attr_id == CM_REP_ATTR_ID) {
        id = id_map_alloc(ibdev, slave_id, sl_cm_id);
        if (IS_ERR(id)) {
            mlx4_ib_warn(ibdev, "%s: id{slave: %d, sl_cm_id: 0x%x} Failed to id_map_alloc\n",
                __func__, slave_id, sl_cm_id);
            return PTR_ERR(id);
        }
    } else if (mad->mad_hdr.attr_id == CM_REJ_ATTR_ID) {
        return 0;
    } else {
        id = id_map_get(ibdev, &pv_cm_id, slave_id, sl_cm_id);
    }

    if (!id) {
        pr_debug("id{slave: %d, sl_cm_id: 0x%x} is NULL!\n",
             slave_id, sl_cm_id);
        return -EINVAL;
    }

    set_local_comm_id(mad, id->pv_cm_id);

    if (mad->mad_hdr.attr_id == CM_DREQ_ATTR_ID)
        schedule_delayed(ibdev, id);
    else if (mad->mad_hdr.attr_id == CM_DREP_ATTR_ID)
        id_map_find_del(ibdev, pv_cm_id);

    return 0;
}

int mlx4_ib_demux_cm_handler(struct ib_device *ibdev, int port, int *slave,
                                 struct ib_mad *mad)
{
    u32 pv_cm_id;
    struct id_map_entry *id;

    if (mad->mad_hdr.attr_id == CM_REQ_ATTR_ID) {
        union ib_gid gid;

        gid = gid_from_req_msg(ibdev, mad);
        *slave = mlx4_ib_find_real_gid(ibdev, port, gid.global.interface_id);
        if (*slave < 0) {
            mlx4_ib_warn(ibdev, "failed matching slave_id by gid (0x%llx)\n",
                    gid.global.interface_id);
            return -ENOENT;
        }
        return 0;
    }

    pv_cm_id = get_remote_comm_id(mad);
    id = id_map_get(ibdev, (int *)&pv_cm_id, -1, -1);

    if (!id) {
        pr_debug("Couldn't find an entry for pv_cm_id 0x%x\n", pv_cm_id);
        return -ENOENT;
    }

    *slave = id->slave_id;
    set_remote_comm_id(mad, id->sl_cm_id);

    if (mad->mad_hdr.attr_id == CM_DREQ_ATTR_ID)
        schedule_delayed(ibdev, id);
    else if (mad->mad_hdr.attr_id == CM_REJ_ATTR_ID ||
            mad->mad_hdr.attr_id == CM_DREP_ATTR_ID) {
        id_map_find_del(ibdev, (int) pv_cm_id);
    }

    return 0;
}

void mlx4_ib_cm_paravirt_init(struct mlx4_ib_dev *dev)
{
    spin_lock_init(&dev->sriov.id_map_lock);
    INIT_LIST_HEAD(&dev->sriov.cm_list);
    dev->sriov.sl_id_map = RB_ROOT;
    idr_init(&dev->sriov.pv_id_table);
    idr_pre_get(&dev->sriov.pv_id_table, GFP_KERNEL);
}

/* slave = -1 ==> all slaves */
/* TBD -- call paravirt clean for single slave.  Need for slave RESET event */
void mlx4_ib_cm_paravirt_clean(struct mlx4_ib_dev *dev, int slave)
{
    struct mlx4_ib_sriov *sriov = &dev->sriov;
    struct rb_root *sl_id_map = &sriov->sl_id_map;
    struct list_head lh;
    struct rb_node *nd;
    int need_flush = 1;
    struct id_map_entry *map, *tmp_map;
    /* cancel all delayed work queue entries */
    INIT_LIST_HEAD(&lh);
    spin_lock(&sriov->id_map_lock);
    list_for_each_entry_safe(map, tmp_map, &dev->sriov.cm_list, list) {
        if (slave < 0 || slave == map->slave_id) {
            if (map->scheduled_delete)
                need_flush &= !!cancel_delayed_work(&map->timeout);
        }
    }

    spin_unlock(&sriov->id_map_lock);

    if (!need_flush)
        flush_scheduled_work(); /* make sure all timers were flushed */

    /* now, remove all leftover entries from databases*/
    spin_lock(&sriov->id_map_lock);
    if (slave < 0) {
        while (rb_first(sl_id_map)) {
            struct id_map_entry *ent =
                rb_entry(rb_first(sl_id_map),
                     struct id_map_entry, node);

            rb_erase(&ent->node, sl_id_map);
            idr_remove(&sriov->pv_id_table, (int) ent->pv_cm_id);
        }
        list_splice_init(&dev->sriov.cm_list, &lh);
    } else {
        /* first, move nodes belonging to slave to db remove list */
        nd = rb_first(sl_id_map);
        while (nd) {
            struct id_map_entry *ent =
                rb_entry(nd, struct id_map_entry, node);
            nd = rb_next(nd);
            if (ent->slave_id == slave)
                list_move_tail(&ent->list, &lh);
        }
        /* remove those nodes from databases */
        list_for_each_entry_safe(map, tmp_map, &lh, list) {
            rb_erase(&map->node, sl_id_map);
            idr_remove(&sriov->pv_id_table, (int) map->pv_cm_id);
        }

        /* add remaining nodes from cm_list */
        list_for_each_entry_safe(map, tmp_map, &dev->sriov.cm_list, list) {
            if (slave == map->slave_id)
                list_move_tail(&map->list, &lh);
        }
    }

    spin_unlock(&sriov->id_map_lock);

    /* free any map entries left behind due to cancel_delayed_work above */
    list_for_each_entry_safe(map, tmp_map, &lh, list) {
        list_del(&map->list);
        kfree(map);
    }
}