cxgb3 - Add LRO support

Add LRO support.

Signed-off-by: Divy Le Ray <divy@chelsio.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 221 insertions, 12 deletions

diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c
index 3e91be55e19e..a96331c875e6 100644
--- a/drivers/net/cxgb3/sge.c
+++ b/drivers/net/cxgb3/sge.c
@@ -584,6 +584,8 @@ static void t3_reset_qset(struct sge_qset *q)
         memset(q->txq, 0, sizeof(struct sge_txq) * SGE_TXQ_PER_SET);
         q->txq_stopped = 0;
         memset(&q->tx_reclaim_timer, 0, sizeof(q->tx_reclaim_timer));
+        kfree(q->lro_frag_tbl);
+        q->lro_nfrags = q->lro_frag_len = 0;
 }
 
 
@@ -796,7 +798,7 @@ recycle:
                 goto recycle;
 
         if (!skb)
-                newskb = alloc_skb(SGE_RX_PULL_LEN, GFP_ATOMIC);        
+                newskb = alloc_skb(SGE_RX_PULL_LEN, GFP_ATOMIC);
         if (unlikely(!newskb)) {
                 if (!drop_thres)
                         return NULL;
@@ -1868,9 +1870,10 @@ static void restart_tx(struct sge_qset *qs)
  *      if it was immediate data in a response.
  */
 static void rx_eth(struct adapter *adap, struct sge_rspq *rq,
-                   struct sk_buff *skb, int pad)
+                   struct sk_buff *skb, int pad, int lro)
 {
         struct cpl_rx_pkt *p = (struct cpl_rx_pkt *)(skb->data + pad);
+        struct sge_qset *qs = rspq_to_qset(rq);
         struct port_info *pi;
 
         skb_pull(skb, sizeof(*p) + pad);
@@ -1887,18 +1890,202 @@ static void rx_eth(struct adapter *adap, struct sge_rspq *rq,
         if (unlikely(p->vlan_valid)) {
                 struct vlan_group *grp = pi->vlan_grp;
 
-                rspq_to_qset(rq)->port_stats[SGE_PSTAT_VLANEX]++;
+                qs->port_stats[SGE_PSTAT_VLANEX]++;
                 if (likely(grp))
-                        __vlan_hwaccel_rx(skb, grp, ntohs(p->vlan),
-                                          rq->polling);
+                        if (lro)
+                                lro_vlan_hwaccel_receive_skb(&qs->lro_mgr, skb,
+                                                             grp,
+                                                             ntohs(p->vlan),
+                                                             p);
+                        else
+                                __vlan_hwaccel_rx(skb, grp, ntohs(p->vlan),
+                                                  rq->polling);
                 else
                         dev_kfree_skb_any(skb);
-        } else if (rq->polling)
-                netif_receive_skb(skb);
-        else
+        } else if (rq->polling) {
+                if (lro)
+                        lro_receive_skb(&qs->lro_mgr, skb, p);
+                else
+                        netif_receive_skb(skb);
+        } else
                 netif_rx(skb);
 }
 
+static inline int is_eth_tcp(u32 rss)
+{
+        return G_HASHTYPE(ntohl(rss)) == RSS_HASH_4_TUPLE;
+}
+
+/**
+ *      lro_frame_ok - check if an ingress packet is eligible for LRO
+ *      @p: the CPL header of the packet
+ *
+ *      Returns true if a received packet is eligible for LRO.
+ *      The following conditions must be true:
+ *      - packet is TCP/IP Ethernet II (checked elsewhere)
+ *      - not an IP fragment
+ *      - no IP options
+ *      - TCP/IP checksums are correct
+ *      - the packet is for this host
+ */
+static inline int lro_frame_ok(const struct cpl_rx_pkt *p)
+{
+        const struct ethhdr *eh = (struct ethhdr *)(p + 1);
+        const struct iphdr *ih = (struct iphdr *)(eh + 1);
+
+        return (*((u8 *)p + 1) & 0x90) == 0x10 && p->csum == htons(0xffff) &&
+                eh->h_proto == htons(ETH_P_IP) && ih->ihl == (sizeof(*ih) >> 2);
+}
+
+#define TCP_FLAG_MASK (TCP_FLAG_CWR | TCP_FLAG_ECE | TCP_FLAG_URG |\
+                       TCP_FLAG_ACK | TCP_FLAG_PSH | TCP_FLAG_RST |\
+                                       TCP_FLAG_SYN | TCP_FLAG_FIN)
+#define TSTAMP_WORD ((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |\
+                     (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP)
+
+/**
+ *      lro_segment_ok - check if a TCP segment is eligible for LRO
+ *      @tcph: the TCP header of the packet
+ *
+ *      Returns true if a TCP packet is eligible for LRO.  This requires that
+ *      the packet have only the ACK flag set and no TCP options besides
+ *      time stamps.
+ */
+static inline int lro_segment_ok(const struct tcphdr *tcph)
+{
+        int optlen;
+
+        if (unlikely((tcp_flag_word(tcph) & TCP_FLAG_MASK) != TCP_FLAG_ACK))
+                return 0;
+
+        optlen = (tcph->doff << 2) - sizeof(*tcph);
+        if (optlen) {
+                const u32 *opt = (const u32 *)(tcph + 1);
+
+                if (optlen != TCPOLEN_TSTAMP_ALIGNED ||
+                    *opt != htonl(TSTAMP_WORD) || !opt[2])
+                        return 0;
+        }
+        return 1;
+}
+
+static int t3_get_lro_header(void **eh,  void **iph, void **tcph,
+                             u64 *hdr_flags, void *priv)
+{
+        const struct cpl_rx_pkt *cpl = priv;
+
+        if (!lro_frame_ok(cpl))
+                return -1;
+
+        *eh = (struct ethhdr *)(cpl + 1);
+        *iph = (struct iphdr *)((struct ethhdr *)*eh + 1);
+        *tcph = (struct tcphdr *)((struct iphdr *)*iph + 1);
+
+         if (!lro_segment_ok(*tcph))
+                return -1;
+
+        *hdr_flags = LRO_IPV4 | LRO_TCP;
+        return 0;
+}
+
+static int t3_get_skb_header(struct sk_buff *skb,
+                              void **iph, void **tcph, u64 *hdr_flags,
+                              void *priv)
+{
+        void *eh;
+
+        return t3_get_lro_header(&eh, iph, tcph, hdr_flags, priv);
+}
+
+static int t3_get_frag_header(struct skb_frag_struct *frag, void **eh,
+                              void **iph, void **tcph, u64 *hdr_flags,
+                              void *priv)
+{
+        return t3_get_lro_header(eh, iph, tcph, hdr_flags, priv);
+}
+
+/**
+ *      lro_add_page - add a page chunk to an LRO session
+ *      @adap: the adapter
+ *      @qs: the associated queue set
+ *      @fl: the free list containing the page chunk to add
+ *      @len: packet length
+ *      @complete: Indicates the last fragment of a frame
+ *
+ *      Add a received packet contained in a page chunk to an existing LRO
+ *      session.
+ */
+static void lro_add_page(struct adapter *adap, struct sge_qset *qs,
+                         struct sge_fl *fl, int len, int complete)
+{
+        struct rx_sw_desc *sd = &fl->sdesc[fl->cidx];
+        struct cpl_rx_pkt *cpl;
+        struct skb_frag_struct *rx_frag = qs->lro_frag_tbl;
+        int nr_frags = qs->lro_nfrags, frag_len = qs->lro_frag_len;
+        int offset = 0;
+
+        if (!nr_frags) {
+                offset = 2 + sizeof(struct cpl_rx_pkt);
+                qs->lro_va = cpl = sd->pg_chunk.va + 2;
+        }
+
+        fl->credits--;
+
+        len -= offset;
+        pci_unmap_single(adap->pdev, pci_unmap_addr(sd, dma_addr),
+                         fl->buf_size, PCI_DMA_FROMDEVICE);
+
+        rx_frag += nr_frags;
+        rx_frag->page = sd->pg_chunk.page;
+        rx_frag->page_offset = sd->pg_chunk.offset + offset;
+        rx_frag->size = len;
+        frag_len += len;
+        qs->lro_nfrags++;
+        qs->lro_frag_len = frag_len;
+
+        if (!complete)
+                return;
+
+        qs->lro_nfrags = qs->lro_frag_len = 0;
+        cpl = qs->lro_va;
+
+        if (unlikely(cpl->vlan_valid)) {
+                struct net_device *dev = qs->netdev;
+                struct port_info *pi = netdev_priv(dev);
+                struct vlan_group *grp = pi->vlan_grp;
+
+                if (likely(grp != NULL)) {
+                        lro_vlan_hwaccel_receive_frags(&qs->lro_mgr,
+                                                       qs->lro_frag_tbl,
+                                                       frag_len, frag_len,
+                                                       grp, ntohs(cpl->vlan),
+                                                       cpl, 0);
+                        return;
+                }
+        }
+        lro_receive_frags(&qs->lro_mgr, qs->lro_frag_tbl,
+                          frag_len, frag_len, cpl, 0);
+}
+
+/**
+ *      init_lro_mgr - initialize a LRO manager object
+ *      @lro_mgr: the LRO manager object
+ */
+static void init_lro_mgr(struct sge_qset *qs, struct net_lro_mgr *lro_mgr)
+{
+        lro_mgr->dev = qs->netdev;
+        lro_mgr->features = LRO_F_NAPI;
+        lro_mgr->ip_summed = CHECKSUM_UNNECESSARY;
+        lro_mgr->ip_summed_aggr = CHECKSUM_UNNECESSARY;
+        lro_mgr->max_desc = T3_MAX_LRO_SES;
+        lro_mgr->lro_arr = qs->lro_desc;
+        lro_mgr->get_frag_header = t3_get_frag_header;
+        lro_mgr->get_skb_header = t3_get_skb_header;
+        lro_mgr->max_aggr = T3_MAX_LRO_MAX_PKTS;
+        if (lro_mgr->max_aggr > MAX_SKB_FRAGS)
+                lro_mgr->max_aggr = MAX_SKB_FRAGS;
+}
+
 /**
  *      handle_rsp_cntrl_info - handles control information in a response
  *      @qs: the queue set corresponding to the response
@@ -2027,7 +2214,7 @@ static int process_responses(struct adapter *adap, struct sge_qset *qs,
         q->next_holdoff = q->holdoff_tmr;
 
         while (likely(budget_left && is_new_response(r, q))) {
-                int packet_complete, eth, ethpad = 2;
+                int packet_complete, eth, ethpad = 2, lro = qs->lro_enabled;
                 struct sk_buff *skb = NULL;
                 u32 len, flags = ntohl(r->flags);
                 __be32 rss_hi = *(const __be32 *)r,
@@ -2059,6 +2246,9 @@ no_mem:
                 } else if ((len = ntohl(r->len_cq)) != 0) {
                         struct sge_fl *fl;
 
+                        if (eth)
+                                lro = qs->lro_enabled && is_eth_tcp(rss_hi);
+
                         fl = (len & F_RSPD_FLQ) ? &qs->fl[1] : &qs->fl[0];
                         if (fl->use_pages) {
                                 void *addr = fl->sdesc[fl->cidx].pg_chunk.va;
@@ -2068,6 +2258,12 @@ no_mem:
                                 prefetch(addr + L1_CACHE_BYTES);
 #endif
                                 __refill_fl(adap, fl);
+                                if (lro > 0) {
+                                        lro_add_page(adap, qs, fl,
+                                                     G_RSPD_LEN(len),
+                                                     flags & F_RSPD_EOP);
+                                         goto next_fl;
+                                }
 
                                 skb = get_packet_pg(adap, fl, q,
                                                     G_RSPD_LEN(len),
@@ -2083,7 +2279,7 @@ no_mem:
                                 q->rx_drops++;
                         } else if (unlikely(r->rss_hdr.opcode == CPL_TRACE_PKT))
                                 __skb_pull(skb, 2);
-
+next_fl:
                         if (++fl->cidx == fl->size)
                                 fl->cidx = 0;
                 } else
@@ -2113,7 +2309,7 @@ no_mem:
 
                 if (skb != NULL && packet_complete) {
                         if (eth)
-                                rx_eth(adap, q, skb, ethpad);
+                                rx_eth(adap, q, skb, ethpad, lro);
                         else {
                                 q->offload_pkts++;
                                 /* Preserve the RSS info in csum & priority */
@@ -2125,12 +2321,17 @@ no_mem:
                         }
 
                         if (flags & F_RSPD_EOP)
-                                clear_rspq_bufstate(q); 
+                                clear_rspq_bufstate(q);
                 }
                 --budget_left;
         }
 
         deliver_partial_bundle(&adap->tdev, q, offload_skbs, ngathered);
+        lro_flush_all(&qs->lro_mgr);
+        qs->port_stats[SGE_PSTAT_LRO_AGGR] = qs->lro_mgr.stats.aggregated;
+        qs->port_stats[SGE_PSTAT_LRO_FLUSHED] = qs->lro_mgr.stats.flushed;
+        qs->port_stats[SGE_PSTAT_LRO_NO_DESC] = qs->lro_mgr.stats.no_desc;
+
         if (sleeping)
                 check_ring_db(adap, qs, sleeping);
 
@@ -2674,6 +2875,7 @@ int t3_sge_alloc_qset(struct adapter *adapter, unsigned int id, int nports,
 {
         int i, avail, ret = -ENOMEM;
         struct sge_qset *q = &adapter->sge.qs[id];
+        struct net_lro_mgr *lro_mgr = &q->lro_mgr;
 
         init_qset_cntxt(q, id);
         init_timer(&q->tx_reclaim_timer);
@@ -2754,6 +2956,10 @@ int t3_sge_alloc_qset(struct adapter *adapter, unsigned int id, int nports,
         q->fl[0].order = FL0_PG_ORDER;
         q->fl[1].order = FL1_PG_ORDER;
 
+        q->lro_frag_tbl = kcalloc(MAX_FRAME_SIZE / FL1_PG_CHUNK_SIZE + 1,
+                                  sizeof(struct skb_frag_struct),
+                                  GFP_KERNEL);
+        q->lro_nfrags = q->lro_frag_len = 0;
         spin_lock_irq(&adapter->sge.reg_lock);
 
         /* FL threshold comparison uses < */
@@ -2803,6 +3009,9 @@ int t3_sge_alloc_qset(struct adapter *adapter, unsigned int id, int nports,
         q->adap = adapter;
         q->netdev = dev;
         t3_update_qset_coalesce(q, p);
+
+        init_lro_mgr(q, lro_mgr);
+
         avail = refill_fl(adapter, &q->fl[0], q->fl[0].size,
                           GFP_KERNEL | __GFP_COMP);
         if (!avail) {