[openib-general] [PATCH 16/18] [RFC] cxgb3 Core L2 Neighbour Management
Steve Wise
swise at opengridcomputing.com
Mon Mar 6 10:10:55 PST 2006
This code manages the hardware's neighbour table and thus hooks into the
native L2/L3 stack. Currently we're using Tom's notifier patch to
detect neighbour changes. This needs more discussion on how RNICs
should be made aware of next hop changes...
--- old/src/linux-kernel/infiniband/hw/cxgb3/t3c/l2t.c 1969-12-31 18:00:00.000000000 -0600
+++ new/src/linux-kernel/infiniband/hw/cxgb3/t3c/l2t.c 2006-03-06 09:26:21.000000000 -0600
@@ -0,0 +1,537 @@
+/*
+ * Copyright (c) 2006 Chelsio, Inc. All rights reserved.
+ * Copyright (c) 2006 Open Grid Computing, 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 <net/neighbour.h>
+#include "t3cdev.h"
+#include "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.
+ *
+ * Note: We do not take refereces to net_devices in this module because both
+ * the TOE and the sockets already hold references to the interfaces and the
+ * lifetime of an L2T entry is fully contained in the lifetime of the TOE.
+ */
+
+static inline unsigned int vlan_prio(const struct l2t_entry *e)
+{
+ return e->vlan >> 13;
+}
+
+static inline void l2t_hold(struct l2t_data *d, struct l2t_entry *e)
+{
+ if (atomic_add_return(1, &e->refcnt) == 1) /* 0 -> 1 transition */
+ atomic_dec(&d->nfree);
+}
+
+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;
+
+ 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;
+ t3c_send(dev, skb);
+ while (e->arpq_head) {
+ skb = e->arpq_head;
+ e->arpq_head = skb->next;
+ skb->next = NULL;
+ t3c_send(dev, skb);
+ }
+ e->arpq_tail = NULL;
+ 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->next = NULL;
+ if (e->arpq_head)
+ e->arpq_tail->next = skb;
+ else
+ e->arpq_head = skb;
+ e->arpq_tail = 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 t3c_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 (e->arpq_head)
+ 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);
+
+/*
+ * 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;
+ }
+ /*
+ * Don't need to worry about the arpq, an L2T entry can't be
+ * released if any packets are waiting for resolution as we
+ * need to be able to communicate with the TOE to close a
+ * connection.
+ */
+ }
+ 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 *dev, struct neighbour *neigh,
+ unsigned int smt_idx)
+{
+ 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);
+
+ 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_INFO(neigh->dev)->vlan_id;
+ 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 TOE.
+ *
+ * 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 *arpq)
+{
+ while (arpq) {
+ struct sk_buff *skb = arpq;
+ struct l2t_skb_cb *cb = L2T_SKB_CB(skb);
+
+ arpq = skb->next;
+ skb->next = NULL;
+ if (cb->arp_failure_handler)
+ cb->arp_failure_handler(dev, skb);
+ else
+ t3c_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, int flags, struct net_device *lldev)
+{
+ struct l2t_entry *e;
+ struct sk_buff *arpq = NULL;
+ 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:
+ 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) {
+ arpq = e->arpq_head;
+ e->arpq_head = e->arpq_tail = NULL;
+ } else if (neigh_is_connected(neigh) && e->arpq_head)
+ setup_l2e_send_pending(dev, NULL, e);
+ } else {
+ e->state = neigh_is_connected(neigh) ?
+ 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 (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 = t3_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;
+ spin_lock_init(&d->l2tab[i].lock);
+ atomic_set(&d->l2tab[i].refcnt, 0);
+ }
+ return d;
+}
+
+void t3_free_l2t(struct l2t_data *d)
+{
+ t3_free_mem(d);
+}
+
+#ifdef CONFIG_PROC_FS
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+static inline void *l2t_get_idx(struct seq_file *seq, loff_t pos)
+{
+ struct l2t_data *d = seq->private;
+
+ return pos >= d->nentries ? NULL : &d->l2tab[pos];
+}
+
+static void *l2t_seq_start(struct seq_file *seq, loff_t *pos)
+{
+ return *pos ? l2t_get_idx(seq, *pos) : SEQ_START_TOKEN;
+}
+
+static void *l2t_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ v = l2t_get_idx(seq, *pos + 1);
+ if (v)
+ ++*pos;
+ return v;
+}
+
+static void l2t_seq_stop(struct seq_file *seq, void *v)
+{
+}
+
+static char l2e_state(const struct l2t_entry *e)
+{
+ switch (e->state) {
+ case L2T_STATE_VALID: return 'V'; /* valid, fast-path entry */
+ case L2T_STATE_STALE: return 'S'; /* needs revalidation, but usable */
+ case L2T_STATE_RESOLVING:
+ return e->arpq_head ? 'A' : 'R';
+ default:
+ return 'U';
+ }
+}
+
+static int l2t_seq_show(struct seq_file *seq, void *v)
+{
+ if (v == SEQ_START_TOKEN)
+ seq_puts(seq, "Index IP address Ethernet address VLAN "
+ "Prio State Users SMTIDX Port\n");
+ else {
+ char ip[20];
+ struct l2t_entry *e = v;
+
+ spin_lock_bh(&e->lock);
+ sprintf(ip, "%u.%u.%u.%u", NIPQUAD(e->addr));
+ seq_printf(seq, "%-5u %-15s %02x:%02x:%02x:%02x:%02x:%02x %4d"
+ " %3u %c %7u %4u %s\n",
+ e->idx, ip, e->dmac[0], e->dmac[1], e->dmac[2],
+ e->dmac[3], e->dmac[4], e->dmac[5],
+ e->vlan & VLAN_VID_MASK, vlan_prio(e),
+ l2e_state(e), atomic_read(&e->refcnt), e->smt_idx,
+ e->neigh ? e->neigh->dev->name : "");
+ spin_unlock_bh(&e->lock);
+ }
+ return 0;
+}
+
+static struct seq_operations l2t_seq_ops = {
+ .start = l2t_seq_start,
+ .next = l2t_seq_next,
+ .stop = l2t_seq_stop,
+ .show = l2t_seq_show
+};
+
+static int l2t_seq_open(struct inode *inode, struct file *file)
+{
+ int rc = seq_open(file, &l2t_seq_ops);
+
+ if (!rc) {
+ struct proc_dir_entry *dp = PDE(inode);
+ struct seq_file *seq = file->private_data;
+
+ seq->private = dp->data;
+ }
+ return rc;
+}
+
+static struct file_operations l2t_seq_fops = {
+ .owner = THIS_MODULE,
+ .open = l2t_seq_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+/*
+ * Create the proc entries for the L2 table under dir.
+ */
+int t3_l2t_proc_setup(struct proc_dir_entry *dir, struct l2t_data *d)
+{
+ struct proc_dir_entry *p;
+
+ if (!dir)
+ return -EINVAL;
+
+ p = create_proc_entry("l2t", S_IRUGO, dir);
+ if (!p)
+ return -ENOMEM;
+
+ p->proc_fops = &l2t_seq_fops;
+ p->data = d;
+ return 0;
+}
+
+void t3_l2t_proc_free(struct proc_dir_entry *dir)
+{
+ if (dir)
+ remove_proc_entry("l2t", dir);
+}
+#endif
--- old/src/linux-kernel/infiniband/hw/cxgb3/t3c/l2t.h 1969-12-31 18:00:00.000000000 -0600
+++ new/src/linux-kernel/infiniband/hw/cxgb3/t3c/l2t.h 2006-03-06 09:26:21.000000000 -0600
@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2006 Chelsio, Inc. All rights reserved.
+ * Copyright (c) 2006 Open Grid Computing, 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.
+ */
+#ifndef _CHELSIO_L2T_H
+#define _CHELSIO_L2T_H
+
+#include <linux/config.h>
+#include <linux/spinlock.h>
+#include "t3cdev.h"
+#include <asm/atomic.h>
+
+enum {
+ L2T_STATE_VALID, /* entry is up to date */
+ L2T_STATE_STALE, /* entry may be used but needs revalidation */
+ L2T_STATE_RESOLVING, /* entry needs address resolution */
+ L2T_STATE_UNUSED /* entry not in use */
+};
+
+struct neighbour;
+struct sk_buff;
+
+/*
+ * Each L2T entry plays multiple roles. First of all, it keeps state for the
+ * corresponding entry of the HW L2 table and maintains a queue of offload
+ * packets awaiting address resolution. Second, it is a node of a hash table
+ * chain, where the nodes of the chain are linked together through their next
+ * pointer. Finally, each node is a bucket of a hash table, pointing to the
+ * first element in its chain through its first pointer.
+ */
+struct l2t_entry {
+ u16 state; /* entry state */
+ u16 idx; /* entry index */
+ u32 addr; /* dest IP address */
+ int ifindex; /* neighbor's net_device's ifindex */
+ u16 smt_idx; /* SMT index */
+ u16 vlan; /* VLAN TCI (id: bits 0-11, prio: 13-15 */
+ struct neighbour *neigh; /* associated neighbour */
+ struct l2t_entry *first; /* start of hash chain */
+ struct l2t_entry *next; /* next l2t_entry on chain */
+ struct sk_buff *arpq_head; /* queue of packets awaiting resolution */
+ struct sk_buff *arpq_tail;
+ spinlock_t lock;
+ atomic_t refcnt; /* entry reference count */
+ u8 dmac[6]; /* neighbour's MAC address */
+};
+
+struct l2t_data {
+ unsigned int nentries; /* number of entries */
+ struct l2t_entry *rover; /* starting point for next allocation */
+ atomic_t nfree; /* number of free entries */
+ rwlock_t lock;
+ struct l2t_entry l2tab[0];
+};
+
+typedef void (*arp_failure_handler_t)(struct t3cdev *dev, struct sk_buff *skb);
+
+/*
+ * Callback stored in an skb to handle address resolution failure.
+ */
+struct l2t_skb_cb {
+ arp_failure_handler_t arp_failure_handler;
+};
+
+#define L2T_SKB_CB(skb) ((struct l2t_skb_cb *)(skb)->cb)
+
+static inline void set_arp_failure_handler(struct sk_buff *skb,
+ arp_failure_handler_t hnd)
+{
+ L2T_SKB_CB(skb)->arp_failure_handler = hnd;
+}
+
+/*
+ * Getting to the L2 data from a toe device.
+ */
+#define L2DATA(dev) ((dev)->l2opt)
+
+void t3_l2e_free(struct l2t_data *d, struct l2t_entry *e);
+void t3_l2t_update(struct t3cdev *dev, struct neighbour *neigh, int flags, struct net_device *lldev);
+struct l2t_entry *t3_l2t_get(struct t3cdev *dev, struct neighbour *neigh,
+ unsigned int smt_idx);
+int t3_l2t_send_slow(struct t3cdev *dev, struct sk_buff *skb,
+ struct l2t_entry *e);
+struct l2t_data *t3_init_l2t(unsigned int l2t_capacity);
+void t3_free_l2t(struct l2t_data *d);
+
+#ifdef CONFIG_PROC_FS
+int t3_l2t_proc_setup(struct proc_dir_entry *dir, struct l2t_data *d);
+void t3_l2t_proc_free(struct proc_dir_entry *dir);
+#else
+#define l2t_proc_setup(dir, d) 0
+#define l2t_proc_free(dir)
+#endif
+
+int t3c_send(struct t3cdev *dev, struct sk_buff *skb);
+
+static inline int l2t_send(struct t3cdev *dev, struct sk_buff *skb,
+ struct l2t_entry *e)
+{
+ if (likely(e->state == L2T_STATE_VALID))
+ return t3c_send(dev, skb);
+ return t3_l2t_send_slow(dev, skb, e);
+}
+
+static inline void l2t_release(struct l2t_data *d, struct l2t_entry *e)
+{
+ if (atomic_dec_and_test(&e->refcnt))
+ t3_l2e_free(d, e);
+}
+#endif
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