FreeBSD/Linux Kernel Cross Reference
sys/dev/cxgbe/t4_l2t.c

     /*-
      * Copyright (c) 2012 Chelsio Communications, Inc.
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. 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.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/8.4/sys/dev/cxgbe/t4_l2t.c 247670 2013-03-02 21:59:07Z np $");
    
    #include "opt_inet.h"
    #include "opt_inet6.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/bus.h>
    #include <sys/lock.h>
    #include <sys/mutex.h>
    #include <sys/rwlock.h>
    #include <sys/socket.h>
    #include <sys/sbuf.h>
    #include <netinet/in.h>
    
    #include "common/common.h"
    #include "common/t4_msg.h"
    #include "t4_l2t.h"
    
    /*
     * 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 ifnets 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.
     */
    
    /*
     * Allocate a free L2T entry.  Must be called with l2t_data.lock held.
     */
    struct l2t_entry *
    t4_alloc_l2e(struct l2t_data *d)
    {
            struct l2t_entry *end, *e, **p;
    
            rw_assert(&d->lock, RA_WLOCKED);
    
            if (!atomic_load_acq_int(&d->nfree))
                    return (NULL);
    
            /* there's definitely a free entry */
            for (e = d->rover, end = &d->l2tab[d->l2t_size]; e != end; ++e)
                    if (atomic_load_acq_int(&e->refcnt) == 0)
                            goto found;
    
            for (e = d->l2tab; atomic_load_acq_int(&e->refcnt); ++e)
                    continue;
    found:
            d->rover = e + 1;
            atomic_subtract_int(&d->nfree, 1);
    
            /*
             * 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_SWITCHING) {
                    for (p = &d->l2tab[e->hash].first; *p; p = &(*p)->next) {
                            if (*p == e) {
                                    *p = e->next;
                                    e->next = NULL;
                                    break;
                           }
                   }
           }
   
           e->state = L2T_STATE_UNUSED;
           return (e);
   }
   
   /*
    * Write an L2T entry.  Must be called with the entry locked.
    * The write may be synchronous or asynchronous.
    */
   int
   t4_write_l2e(struct adapter *sc, struct l2t_entry *e, int sync)
   {
           struct wrqe *wr;
           struct cpl_l2t_write_req *req;
           int idx = e->idx + sc->vres.l2t.start;
   
           mtx_assert(&e->lock, MA_OWNED);
   
           wr = alloc_wrqe(sizeof(*req), &sc->sge.mgmtq);
           if (wr == NULL)
                   return (ENOMEM);
           req = wrtod(wr);
   
           INIT_TP_WR(req, 0);
           OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_L2T_WRITE_REQ, idx |
               V_SYNC_WR(sync) | V_TID_QID(sc->sge.fwq.abs_id)));
           req->params = htons(V_L2T_W_PORT(e->lport) | V_L2T_W_NOREPLY(!sync));
           req->l2t_idx = htons(idx);
           req->vlan = htons(e->vlan);
           memcpy(req->dst_mac, e->dmac, sizeof(req->dst_mac));
   
           t4_wrq_tx(sc, wr);
   
           if (sync && e->state != L2T_STATE_SWITCHING)
                   e->state = L2T_STATE_SYNC_WRITE;
   
           return (0);
   }
   
   /*
    * Allocate an L2T entry for use by a switching rule.  Such need to be
    * explicitly freed and while busy they are not on any hash chain, so normal
    * address resolution updates do not see them.
    */
   struct l2t_entry *
   t4_l2t_alloc_switching(struct l2t_data *d)
   {
           struct l2t_entry *e;
   
           rw_wlock(&d->lock);
           e = t4_alloc_l2e(d);
           if (e) {
                   mtx_lock(&e->lock);          /* avoid race with t4_l2t_free */
                   e->state = L2T_STATE_SWITCHING;
                   atomic_store_rel_int(&e->refcnt, 1);
                   mtx_unlock(&e->lock);
           }
           rw_wunlock(&d->lock);
           return e;
   }
   
   /*
    * Sets/updates the contents of a switching L2T entry that has been allocated
    * with an earlier call to @t4_l2t_alloc_switching.
    */
   int
   t4_l2t_set_switching(struct adapter *sc, struct l2t_entry *e, uint16_t vlan,
       uint8_t port, uint8_t *eth_addr)
   {
           int rc;
   
           e->vlan = vlan;
           e->lport = port;
           memcpy(e->dmac, eth_addr, ETHER_ADDR_LEN);
           mtx_lock(&e->lock);
           rc = t4_write_l2e(sc, e, 0);
           mtx_unlock(&e->lock);
           return (rc);
   }
   
   int
   t4_init_l2t(struct adapter *sc, int flags)
   {
           int i, l2t_size;
           struct l2t_data *d;
   
           l2t_size = sc->vres.l2t.size;
           if (l2t_size < 2)       /* At least 1 bucket for IP and 1 for IPv6 */
                   return (EINVAL);
   
           d = malloc(sizeof(*d) + l2t_size * sizeof (struct l2t_entry), M_CXGBE,
               M_ZERO | flags);
           if (!d)
                   return (ENOMEM);
   
           d->l2t_size = l2t_size;
           d->rover = d->l2tab;
           atomic_store_rel_int(&d->nfree, l2t_size);
           rw_init(&d->lock, "L2T");
   
           for (i = 0; i < l2t_size; i++) {
                   struct l2t_entry *e = &d->l2tab[i];
   
                   e->idx = i;
                   e->state = L2T_STATE_UNUSED;
                   mtx_init(&e->lock, "L2T_E", NULL, MTX_DEF);
                   STAILQ_INIT(&e->wr_list);
                   atomic_store_rel_int(&e->refcnt, 0);
           }
   
           sc->l2t = d;
           t4_register_cpl_handler(sc, CPL_L2T_WRITE_RPL, do_l2t_write_rpl);
   
           return (0);
   }
   
   int
   t4_free_l2t(struct l2t_data *d)
   {
           int i;
   
           for (i = 0; i < d->l2t_size; i++)
                   mtx_destroy(&d->l2tab[i].lock);
           rw_destroy(&d->lock);
           free(d, M_CXGBE);
   
           return (0);
   }
   
   int
   do_l2t_write_rpl(struct sge_iq *iq, const struct rss_header *rss,
       struct mbuf *m)
   {
           const struct cpl_l2t_write_rpl *rpl = (const void *)(rss + 1);
           unsigned int tid = GET_TID(rpl);
           unsigned int idx = tid % L2T_SIZE;
   
           if (__predict_false(rpl->status != CPL_ERR_NONE)) {
                   log(LOG_ERR,
                       "Unexpected L2T_WRITE_RPL (%u) for entry at hw_idx %u\n",
                       rpl->status, idx);
                   return (EINVAL);
           }
   
           return (0);
   }
   
   #ifdef SBUF_DRAIN
   static inline unsigned int
   vlan_prio(const struct l2t_entry *e)
   {
           return e->vlan >> 13;
   }
   
   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_SYNC_WRITE: return 'W';
           case L2T_STATE_RESOLVING: return STAILQ_EMPTY(&e->wr_list) ? 'R' : 'A';
           case L2T_STATE_SWITCHING: return 'X';
           default: return 'U';
           }
   }
   
   int
   sysctl_l2t(SYSCTL_HANDLER_ARGS)
   {
           struct adapter *sc = arg1;
           struct l2t_data *l2t = sc->l2t;
           struct l2t_entry *e;
           struct sbuf *sb;
           int rc, i, header = 0;
           char ip[INET6_ADDRSTRLEN];
   
           if (l2t == NULL)
                   return (ENXIO);
   
           rc = sysctl_wire_old_buffer(req, 0);
           if (rc != 0)
                   return (rc);
   
           sb = sbuf_new_for_sysctl(NULL, NULL, 4096, req);
           if (sb == NULL)
                   return (ENOMEM);
   
           e = &l2t->l2tab[0];
           for (i = 0; i < l2t->l2t_size; i++, e++) {
                   mtx_lock(&e->lock);
                   if (e->state == L2T_STATE_UNUSED)
                           goto skip;
   
                   if (header == 0) {
                           sbuf_printf(sb, " Idx IP address      "
                               "Ethernet address  VLAN/P LP State Users Port");
                           header = 1;
                   }
                   if (e->state == L2T_STATE_SWITCHING)
                           ip[0] = 0;
                   else {
                           inet_ntop(e->ipv6 ? AF_INET6 : AF_INET, &e->addr[0],
                               &ip[0], sizeof(ip));
                   }
   
                   /*
                    * XXX: e->ifp may not be around.
                    * XXX: IPv6 addresses may not align properly in the output.
                    */
                   sbuf_printf(sb, "\n%4u %-15s %02x:%02x:%02x:%02x:%02x:%02x %4d"
                              " %u %2u   %c   %5u %s",
                              e->idx, ip, e->dmac[0], e->dmac[1], e->dmac[2],
                              e->dmac[3], e->dmac[4], e->dmac[5],
                              e->vlan & 0xfff, vlan_prio(e), e->lport,
                              l2e_state(e), atomic_load_acq_int(&e->refcnt),
                              e->ifp->if_xname);
   skip:
                   mtx_unlock(&e->lock);
           }
   
           rc = sbuf_finish(sb);
           sbuf_delete(sb);
   
           return (rc);
   }
   #endif

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