1 files changed, 445 insertions, 0 deletions

diff --git a/drivers/net/ethernet/chelsio/cxgb3/l2t.c b/drivers/net/ethernet/chelsio/cxgb3/l2t.c
new file mode 100644
index 000000000000..f452c4003253
--- /dev/null
+++ b/drivers/net/ethernet/chelsio/cxgb3/l2t.c
@@ -0,0 +1,445 @@
+/*
+ * Copyright (c) 2003-2008 Chelsio, 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/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/if.h>
+#include <linux/if_vlan.h>
+#include <linux/jhash.h>
+#include <linux/slab.h>
+#include <net/neighbour.h>
+#include "common.h"
+#include "t3cdev.h"
+#include "cxgb3_defs.h"
+#include "l2t.h"
+#include "t3_cpl.h"
+#include "firmware_exports.h"
+
+#define VLAN_NONE 0xfff
+
+/*
+ * Module locking notes:  There is a RW lock protecting the L2 table as a
+ * whole plus a spinlock per L2T entry.  Entry lookups and allocations happen
+ * under the protection of the table lock, individual entry changes happen
+ * while holding that entry's spinlock.  The table lock nests outside the
+ * entry locks.  Allocations of new entries take the table lock as writers so
+ * no other lookups can happen while allocating new entries.  Entry updates
+ * take the table lock as readers so multiple entries can be updated in
+ * parallel.  An L2T entry can be dropped by decrementing its reference count
+ * and therefore can happen in parallel with entry allocation but no entry
+ * can change state or increment its ref count during allocation as both of
+ * these perform lookups.
+ */
+
+static inline unsigned int vlan_prio(const struct l2t_entry *e)
+{
+        return e->vlan >> 13;
+}
+
+static inline unsigned int arp_hash(u32 key, int ifindex,
+                                    const struct l2t_data *d)
+{
+        return jhash_2words(key, ifindex, 0) & (d->nentries - 1);
+}
+
+static inline void neigh_replace(struct l2t_entry *e, struct neighbour *n)
+{
+        neigh_hold(n);
+        if (e->neigh)
+                neigh_release(e->neigh);
+        e->neigh = n;
+}
+
+/*
+ * Set up an L2T entry and send any packets waiting in the arp queue.  The
+ * supplied skb is used for the CPL_L2T_WRITE_REQ.  Must be called with the
+ * entry locked.
+ */
+static int setup_l2e_send_pending(struct t3cdev *dev, struct sk_buff *skb,
+                                  struct l2t_entry *e)
+{
+        struct cpl_l2t_write_req *req;
+        struct sk_buff *tmp;
+
+        if (!skb) {
+                skb = alloc_skb(sizeof(*req), GFP_ATOMIC);
+                if (!skb)
+                        return -ENOMEM;
+        }
+
+        req = (struct cpl_l2t_write_req *)__skb_put(skb, sizeof(*req));
+        req->wr.wr_hi = htonl(V_WR_OP(FW_WROPCODE_FORWARD));
+        OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_L2T_WRITE_REQ, e->idx));
+        req->params = htonl(V_L2T_W_IDX(e->idx) | V_L2T_W_IFF(e->smt_idx) |
+                            V_L2T_W_VLAN(e->vlan & VLAN_VID_MASK) |
+                            V_L2T_W_PRIO(vlan_prio(e)));
+        memcpy(e->dmac, e->neigh->ha, sizeof(e->dmac));
+        memcpy(req->dst_mac, e->dmac, sizeof(req->dst_mac));
+        skb->priority = CPL_PRIORITY_CONTROL;
+        cxgb3_ofld_send(dev, skb);
+
+        skb_queue_walk_safe(&e->arpq, skb, tmp) {
+                __skb_unlink(skb, &e->arpq);
+                cxgb3_ofld_send(dev, skb);
+        }
+        e->state = L2T_STATE_VALID;
+
+        return 0;
+}
+
+/*
+ * Add a packet to the an L2T entry's queue of packets awaiting resolution.
+ * Must be called with the entry's lock held.
+ */
+static inline void arpq_enqueue(struct l2t_entry *e, struct sk_buff *skb)
+{
+        __skb_queue_tail(&e->arpq, skb);
+}
+
+int t3_l2t_send_slow(struct t3cdev *dev, struct sk_buff *skb,
+                     struct l2t_entry *e)
+{
+again:
+        switch (e->state) {
+        case L2T_STATE_STALE:   /* entry is stale, kick off revalidation */
+                neigh_event_send(e->neigh, NULL);
+                spin_lock_bh(&e->lock);
+                if (e->state == L2T_STATE_STALE)
+                        e->state = L2T_STATE_VALID;
+                spin_unlock_bh(&e->lock);
+        case L2T_STATE_VALID:   /* fast-path, send the packet on */
+                return cxgb3_ofld_send(dev, skb);
+        case L2T_STATE_RESOLVING:
+                spin_lock_bh(&e->lock);
+                if (e->state != L2T_STATE_RESOLVING) {
+                        /* ARP already completed */
+                        spin_unlock_bh(&e->lock);
+                        goto again;
+                }
+                arpq_enqueue(e, skb);
+                spin_unlock_bh(&e->lock);
+
+                /*
+                 * Only the first packet added to the arpq should kick off
+                 * resolution.  However, because the alloc_skb below can fail,
+                 * we allow each packet added to the arpq to retry resolution
+                 * as a way of recovering from transient memory exhaustion.
+                 * A better way would be to use a work request to retry L2T
+                 * entries when there's no memory.
+                 */
+                if (!neigh_event_send(e->neigh, NULL)) {
+                        skb = alloc_skb(sizeof(struct cpl_l2t_write_req),
+                                        GFP_ATOMIC);
+                        if (!skb)
+                                break;
+
+                        spin_lock_bh(&e->lock);
+                        if (!skb_queue_empty(&e->arpq))
+                                setup_l2e_send_pending(dev, skb, e);
+                        else    /* we lost the race */
+                                __kfree_skb(skb);
+                        spin_unlock_bh(&e->lock);
+                }
+        }
+        return 0;
+}
+
+EXPORT_SYMBOL(t3_l2t_send_slow);
+
+void t3_l2t_send_event(struct t3cdev *dev, struct l2t_entry *e)
+{
+again:
+        switch (e->state) {
+        case L2T_STATE_STALE:   /* entry is stale, kick off revalidation */
+                neigh_event_send(e->neigh, NULL);
+                spin_lock_bh(&e->lock);
+                if (e->state == L2T_STATE_STALE) {
+                        e->state = L2T_STATE_VALID;
+                }
+                spin_unlock_bh(&e->lock);
+                return;
+        case L2T_STATE_VALID:   /* fast-path, send the packet on */
+                return;
+        case L2T_STATE_RESOLVING:
+                spin_lock_bh(&e->lock);
+                if (e->state != L2T_STATE_RESOLVING) {
+                        /* ARP already completed */
+                        spin_unlock_bh(&e->lock);
+                        goto again;
+                }
+                spin_unlock_bh(&e->lock);
+
+                /*
+                 * Only the first packet added to the arpq should kick off
+                 * resolution.  However, because the alloc_skb below can fail,
+                 * we allow each packet added to the arpq to retry resolution
+                 * as a way of recovering from transient memory exhaustion.
+                 * A better way would be to use a work request to retry L2T
+                 * entries when there's no memory.
+                 */
+                neigh_event_send(e->neigh, NULL);
+        }
+}
+
+EXPORT_SYMBOL(t3_l2t_send_event);
+
+/*
+ * Allocate a free L2T entry.  Must be called with l2t_data.lock held.
+ */
+static struct l2t_entry *alloc_l2e(struct l2t_data *d)
+{
+        struct l2t_entry *end, *e, **p;
+
+        if (!atomic_read(&d->nfree))
+                return NULL;
+
+        /* there's definitely a free entry */
+        for (e = d->rover, end = &d->l2tab[d->nentries]; e != end; ++e)
+                if (atomic_read(&e->refcnt) == 0)
+                        goto found;
+
+        for (e = &d->l2tab[1]; atomic_read(&e->refcnt); ++e) ;
+found:
+        d->rover = e + 1;
+        atomic_dec(&d->nfree);
+
+        /*
+         * The entry we found may be an inactive entry that is
+         * presently in the hash table.  We need to remove it.
+         */
+        if (e->state != L2T_STATE_UNUSED) {
+                int hash = arp_hash(e->addr, e->ifindex, d);
+
+                for (p = &d->l2tab[hash].first; *p; p = &(*p)->next)
+                        if (*p == e) {
+                                *p = e->next;
+                                break;
+                        }
+                e->state = L2T_STATE_UNUSED;
+        }
+        return e;
+}
+
+/*
+ * Called when an L2T entry has no more users.  The entry is left in the hash
+ * table since it is likely to be reused but we also bump nfree to indicate
+ * that the entry can be reallocated for a different neighbor.  We also drop
+ * the existing neighbor reference in case the neighbor is going away and is
+ * waiting on our reference.
+ *
+ * Because entries can be reallocated to other neighbors once their ref count
+ * drops to 0 we need to take the entry's lock to avoid races with a new
+ * incarnation.
+ */
+void t3_l2e_free(struct l2t_data *d, struct l2t_entry *e)
+{
+        spin_lock_bh(&e->lock);
+        if (atomic_read(&e->refcnt) == 0) {     /* hasn't been recycled */
+                if (e->neigh) {
+                        neigh_release(e->neigh);
+                        e->neigh = NULL;
+                }
+        }
+        spin_unlock_bh(&e->lock);
+        atomic_inc(&d->nfree);
+}
+
+EXPORT_SYMBOL(t3_l2e_free);
+
+/*
+ * Update an L2T entry that was previously used for the same next hop as neigh.
+ * Must be called with softirqs disabled.
+ */
+static inline void reuse_entry(struct l2t_entry *e, struct neighbour *neigh)
+{
+        unsigned int nud_state;
+
+        spin_lock(&e->lock);    /* avoid race with t3_l2t_free */
+
+        if (neigh != e->neigh)
+                neigh_replace(e, neigh);
+        nud_state = neigh->nud_state;
+        if (memcmp(e->dmac, neigh->ha, sizeof(e->dmac)) ||
+            !(nud_state & NUD_VALID))
+                e->state = L2T_STATE_RESOLVING;
+        else if (nud_state & NUD_CONNECTED)
+                e->state = L2T_STATE_VALID;
+        else
+                e->state = L2T_STATE_STALE;
+        spin_unlock(&e->lock);
+}
+
+struct l2t_entry *t3_l2t_get(struct t3cdev *cdev, struct neighbour *neigh,
+                             struct net_device *dev)
+{
+        struct l2t_entry *e;
+        struct l2t_data *d = L2DATA(cdev);
+        u32 addr = *(u32 *) neigh->primary_key;
+        int ifidx = neigh->dev->ifindex;
+        int hash = arp_hash(addr, ifidx, d);
+        struct port_info *p = netdev_priv(dev);
+        int smt_idx = p->port_id;
+
+        write_lock_bh(&d->lock);
+        for (e = d->l2tab[hash].first; e; e = e->next)
+                if (e->addr == addr && e->ifindex == ifidx &&
+                    e->smt_idx == smt_idx) {
+                        l2t_hold(d, e);
+                        if (atomic_read(&e->refcnt) == 1)
+                                reuse_entry(e, neigh);
+                        goto done;
+                }
+
+        /* Need to allocate a new entry */
+        e = alloc_l2e(d);
+        if (e) {
+                spin_lock(&e->lock);    /* avoid race with t3_l2t_free */
+                e->next = d->l2tab[hash].first;
+                d->l2tab[hash].first = e;
+                e->state = L2T_STATE_RESOLVING;
+                e->addr = addr;
+                e->ifindex = ifidx;
+                e->smt_idx = smt_idx;
+                atomic_set(&e->refcnt, 1);
+                neigh_replace(e, neigh);
+                if (neigh->dev->priv_flags & IFF_802_1Q_VLAN)
+                        e->vlan = vlan_dev_vlan_id(neigh->dev);
+                else
+                        e->vlan = VLAN_NONE;
+                spin_unlock(&e->lock);
+        }
+done:
+        write_unlock_bh(&d->lock);
+        return e;
+}
+
+EXPORT_SYMBOL(t3_l2t_get);
+
+/*
+ * Called when address resolution fails for an L2T entry to handle packets
+ * on the arpq head.  If a packet specifies a failure handler it is invoked,
+ * otherwise the packets is sent to the offload device.
+ *
+ * XXX: maybe we should abandon the latter behavior and just require a failure
+ * handler.
+ */
+static void handle_failed_resolution(struct t3cdev *dev, struct sk_buff_head *arpq)
+{
+        struct sk_buff *skb, *tmp;
+
+        skb_queue_walk_safe(arpq, skb, tmp) {
+                struct l2t_skb_cb *cb = L2T_SKB_CB(skb);
+
+                __skb_unlink(skb, arpq);
+                if (cb->arp_failure_handler)
+                        cb->arp_failure_handler(dev, skb);
+                else
+                        cxgb3_ofld_send(dev, skb);
+        }
+}
+
+/*
+ * Called when the host's ARP layer makes a change to some entry that is
+ * loaded into the HW L2 table.
+ */
+void t3_l2t_update(struct t3cdev *dev, struct neighbour *neigh)
+{
+        struct sk_buff_head arpq;
+        struct l2t_entry *e;
+        struct l2t_data *d = L2DATA(dev);
+        u32 addr = *(u32 *) neigh->primary_key;
+        int ifidx = neigh->dev->ifindex;
+        int hash = arp_hash(addr, ifidx, d);
+
+        read_lock_bh(&d->lock);
+        for (e = d->l2tab[hash].first; e; e = e->next)
+                if (e->addr == addr && e->ifindex == ifidx) {
+                        spin_lock(&e->lock);
+                        goto found;
+                }
+        read_unlock_bh(&d->lock);
+        return;
+
+found:
+        __skb_queue_head_init(&arpq);
+
+        read_unlock(&d->lock);
+        if (atomic_read(&e->refcnt)) {
+                if (neigh != e->neigh)
+                        neigh_replace(e, neigh);
+
+                if (e->state == L2T_STATE_RESOLVING) {
+                        if (neigh->nud_state & NUD_FAILED) {
+                                skb_queue_splice_init(&e->arpq, &arpq);
+                        } else if (neigh->nud_state & (NUD_CONNECTED|NUD_STALE))
+                                setup_l2e_send_pending(dev, NULL, e);
+                } else {
+                        e->state = neigh->nud_state & NUD_CONNECTED ?
+                            L2T_STATE_VALID : L2T_STATE_STALE;
+                        if (memcmp(e->dmac, neigh->ha, 6))
+                                setup_l2e_send_pending(dev, NULL, e);
+                }
+        }
+        spin_unlock_bh(&e->lock);
+
+        if (!skb_queue_empty(&arpq))
+                handle_failed_resolution(dev, &arpq);
+}
+
+struct l2t_data *t3_init_l2t(unsigned int l2t_capacity)
+{
+        struct l2t_data *d;
+        int i, size = sizeof(*d) + l2t_capacity * sizeof(struct l2t_entry);
+
+        d = cxgb_alloc_mem(size);
+        if (!d)
+                return NULL;
+
+        d->nentries = l2t_capacity;
+        d->rover = &d->l2tab[1];        /* entry 0 is not used */
+        atomic_set(&d->nfree, l2t_capacity - 1);
+        rwlock_init(&d->lock);
+
+        for (i = 0; i < l2t_capacity; ++i) {
+                d->l2tab[i].idx = i;
+                d->l2tab[i].state = L2T_STATE_UNUSED;
+                __skb_queue_head_init(&d->l2tab[i].arpq);
+                spin_lock_init(&d->l2tab[i].lock);
+                atomic_set(&d->l2tab[i].refcnt, 0);
+        }
+        return d;
+}
+
+void t3_free_l2t(struct l2t_data *d)
+{
+        cxgb_free_mem(d);
+}
+