myri10ge: Convert from LRO to GRO

Convert myri10ge from LRO to GRO, and simplify the driver by removing
various LRO-related code which is no longer needed including
ndo_fix_features op, custom skb building from frags, and LRO
header parsing.

Signed-off-by: Andrew Gallatin <gallatin@myri.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 34 insertions, 202 deletions

diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
index 83516e3369c9..84207c04530f 100644
--- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
+++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
@@ -50,7 +50,6 @@
 #include <linux/etherdevice.h>
 #include <linux/if_ether.h>
 #include <linux/if_vlan.h>
-#include <linux/inet_lro.h>
 #include <linux/dca.h>
 #include <linux/ip.h>
 #include <linux/inet.h>
@@ -96,8 +95,6 @@ MODULE_LICENSE("Dual BSD/GPL");
 
 #define MYRI10GE_EEPROM_STRINGS_SIZE 256
 #define MYRI10GE_MAX_SEND_DESC_TSO ((65536 / 2048) * 2)
-#define MYRI10GE_MAX_LRO_DESCRIPTORS 8
-#define MYRI10GE_LRO_MAX_PKTS 64
 
 #define MYRI10GE_NO_CONFIRM_DATA htonl(0xffffffff)
 #define MYRI10GE_NO_RESPONSE_RESULT 0xffffffff
@@ -165,8 +162,6 @@ struct myri10ge_rx_done {
         dma_addr_t bus;
         int cnt;
         int idx;
-        struct net_lro_mgr lro_mgr;
-        struct net_lro_desc lro_desc[MYRI10GE_MAX_LRO_DESCRIPTORS];
 };
 
 struct myri10ge_slice_netstats {
@@ -338,11 +333,6 @@ static int myri10ge_debug = -1;	/* defaults above */
 module_param(myri10ge_debug, int, 0);
 MODULE_PARM_DESC(myri10ge_debug, "Debug level (0=none,...,16=all)");
 
-static int myri10ge_lro_max_pkts = MYRI10GE_LRO_MAX_PKTS;
-module_param(myri10ge_lro_max_pkts, int, S_IRUGO);
-MODULE_PARM_DESC(myri10ge_lro_max_pkts,
-                 "Number of LRO packets to be aggregated");
-
 static int myri10ge_fill_thresh = 256;
 module_param(myri10ge_fill_thresh, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(myri10ge_fill_thresh, "Number of empty rx slots allowed");
@@ -1197,36 +1187,6 @@ static inline void myri10ge_vlan_ip_csum(struct sk_buff *skb, __wsum hw_csum)
         }
 }
 
-static inline void
-myri10ge_rx_skb_build(struct sk_buff *skb, u8 * va,
-                      struct skb_frag_struct *rx_frags, int len, int hlen)
-{
-        struct skb_frag_struct *skb_frags;
-
-        skb->len = skb->data_len = len;
-        /* attach the page(s) */
-
-        skb_frags = skb_shinfo(skb)->frags;
-        while (len > 0) {
-                memcpy(skb_frags, rx_frags, sizeof(*skb_frags));
-                len -= skb_frag_size(rx_frags);
-                skb_frags++;
-                rx_frags++;
-                skb_shinfo(skb)->nr_frags++;
-        }
-
-        /* pskb_may_pull is not available in irq context, but
-         * skb_pull() (for ether_pad and eth_type_trans()) requires
-         * the beginning of the packet in skb_headlen(), move it
-         * manually */
-        skb_copy_to_linear_data(skb, va, hlen);
-        skb_shinfo(skb)->frags[0].page_offset += hlen;
-        skb_frag_size_sub(&skb_shinfo(skb)->frags[0], hlen);
-        skb->data_len -= hlen;
-        skb->tail += hlen;
-        skb_pull(skb, MXGEFW_PAD);
-}
-
 static void
 myri10ge_alloc_rx_pages(struct myri10ge_priv *mgp, struct myri10ge_rx_buf *rx,
                         int bytes, int watchdog)
@@ -1304,18 +1264,14 @@ myri10ge_unmap_rx_page(struct pci_dev *pdev,
         }
 }
 
-#define MYRI10GE_HLEN 64        /* The number of bytes to copy from a
-                                 * page into an skb */
-
 static inline int
-myri10ge_rx_done(struct myri10ge_slice_state *ss, int len, __wsum csum,
-                 bool lro_enabled)
+myri10ge_rx_done(struct myri10ge_slice_state *ss, int len, __wsum csum)
 {
         struct myri10ge_priv *mgp = ss->mgp;
         struct sk_buff *skb;
-        struct skb_frag_struct rx_frags[MYRI10GE_MAX_FRAGS_PER_FRAME];
+        struct skb_frag_struct *rx_frags;
         struct myri10ge_rx_buf *rx;
-        int i, idx, hlen, remainder, bytes;
+        int i, idx, remainder, bytes;
         struct pci_dev *pdev = mgp->pdev;
         struct net_device *dev = mgp->dev;
         u8 *va;
@@ -1332,67 +1288,47 @@ myri10ge_rx_done(struct myri10ge_slice_state *ss, int len, __wsum csum,
         idx = rx->cnt & rx->mask;
         va = page_address(rx->info[idx].page) + rx->info[idx].page_offset;
         prefetch(va);
+
+        skb = napi_get_frags(&ss->napi);
+        if (unlikely(skb == NULL)) {
+                ss->stats.rx_dropped++;
+                for (i = 0, remainder = len; remainder > 0; i++) {
+                        myri10ge_unmap_rx_page(pdev, &rx->info[idx], bytes);
+                        put_page(rx->info[idx].page);
+                        rx->cnt++;
+                        idx = rx->cnt & rx->mask;
+                        remainder -= MYRI10GE_ALLOC_SIZE;
+                }
+                return 0;
+        }
+        rx_frags = skb_shinfo(skb)->frags;
         /* Fill skb_frag_struct(s) with data from our receive */
         for (i = 0, remainder = len; remainder > 0; i++) {
                 myri10ge_unmap_rx_page(pdev, &rx->info[idx], bytes);
-                __skb_frag_set_page(&rx_frags[i], rx->info[idx].page);
-                rx_frags[i].page_offset = rx->info[idx].page_offset;
-                if (remainder < MYRI10GE_ALLOC_SIZE)
-                        skb_frag_size_set(&rx_frags[i], remainder);
-                else
-                        skb_frag_size_set(&rx_frags[i], MYRI10GE_ALLOC_SIZE);
+                skb_fill_page_desc(skb, i, rx->info[idx].page,
+                                   rx->info[idx].page_offset,
+                                   remainder < MYRI10GE_ALLOC_SIZE ?
+                                   remainder : MYRI10GE_ALLOC_SIZE);
                 rx->cnt++;
                 idx = rx->cnt & rx->mask;
                 remainder -= MYRI10GE_ALLOC_SIZE;
         }
 
-        if (lro_enabled) {
-                rx_frags[0].page_offset += MXGEFW_PAD;
-                skb_frag_size_sub(&rx_frags[0], MXGEFW_PAD);
-                len -= MXGEFW_PAD;
-                lro_receive_frags(&ss->rx_done.lro_mgr, rx_frags,
-                                  /* opaque, will come back in get_frag_header */
-                                  len, len,
-                                  (void *)(__force unsigned long)csum, csum);
+        /* remove padding */
+        rx_frags[0].page_offset += MXGEFW_PAD;
+        rx_frags[0].size -= MXGEFW_PAD;
+        len -= MXGEFW_PAD;
 
-                return 1;
-        }
-
-        hlen = MYRI10GE_HLEN > len ? len : MYRI10GE_HLEN;
-
-        /* allocate an skb to attach the page(s) to. This is done
-         * after trying LRO, so as to avoid skb allocation overheads */
-
-        skb = netdev_alloc_skb(dev, MYRI10GE_HLEN + 16);
-        if (unlikely(skb == NULL)) {
-                ss->stats.rx_dropped++;
-                do {
-                        i--;
-                        __skb_frag_unref(&rx_frags[i]);
-                } while (i != 0);
-                return 0;
-        }
-
-        /* Attach the pages to the skb, and trim off any padding */
-        myri10ge_rx_skb_build(skb, va, rx_frags, len, hlen);
-        if (skb_frag_size(&skb_shinfo(skb)->frags[0]) <= 0) {
-                skb_frag_unref(skb, 0);
-                skb_shinfo(skb)->nr_frags = 0;
-        } else {
-                skb->truesize += bytes * skb_shinfo(skb)->nr_frags;
+        skb->len = len;
+        skb->data_len = len;
+        skb->truesize += len;
+        if (dev->features & NETIF_F_RXCSUM) {
+                skb->ip_summed = CHECKSUM_COMPLETE;
+                skb->csum = csum;
         }
-        skb->protocol = eth_type_trans(skb, dev);
         skb_record_rx_queue(skb, ss - &mgp->ss[0]);
 
-        if (dev->features & NETIF_F_RXCSUM) {
-                if ((skb->protocol == htons(ETH_P_IP)) ||
-                    (skb->protocol == htons(ETH_P_IPV6))) {
-                        skb->csum = csum;
-                        skb->ip_summed = CHECKSUM_COMPLETE;
-                } else
-                        myri10ge_vlan_ip_csum(skb, csum);
-        }
-        netif_receive_skb(skb);
+        napi_gro_frags(&ss->napi);
         return 1;
 }
 
@@ -1480,18 +1416,11 @@ myri10ge_clean_rx_done(struct myri10ge_slice_state *ss, int budget)
         u16 length;
         __wsum checksum;
 
-        /*
-         * Prevent compiler from generating more than one ->features memory
-         * access to avoid theoretical race condition with functions that
-         * change NETIF_F_LRO flag at runtime.
-         */
-        bool lro_enabled = !!(ACCESS_ONCE(mgp->dev->features) & NETIF_F_LRO);
-
         while (rx_done->entry[idx].length != 0 && work_done < budget) {
                 length = ntohs(rx_done->entry[idx].length);
                 rx_done->entry[idx].length = 0;
                 checksum = csum_unfold(rx_done->entry[idx].checksum);
-                rx_ok = myri10ge_rx_done(ss, length, checksum, lro_enabled);
+                rx_ok = myri10ge_rx_done(ss, length, checksum);
                 rx_packets += rx_ok;
                 rx_bytes += rx_ok * (unsigned long)length;
                 cnt++;
@@ -1503,9 +1432,6 @@ myri10ge_clean_rx_done(struct myri10ge_slice_state *ss, int budget)
         ss->stats.rx_packets += rx_packets;
         ss->stats.rx_bytes += rx_bytes;
 
-        if (lro_enabled)
-                lro_flush_all(&rx_done->lro_mgr);
-
         /* restock receive rings if needed */
         if (ss->rx_small.fill_cnt - ss->rx_small.cnt < myri10ge_fill_thresh)
                 myri10ge_alloc_rx_pages(mgp, &ss->rx_small,
@@ -1779,7 +1705,6 @@ static const char myri10ge_gstrings_slice_stats[][ETH_GSTRING_LEN] = {
         "tx_pkt_start", "tx_pkt_done", "tx_req", "tx_done",
         "rx_small_cnt", "rx_big_cnt",
         "wake_queue", "stop_queue", "tx_linearized",
-        "LRO aggregated", "LRO flushed", "LRO avg aggr", "LRO no_desc",
 };
 
 #define MYRI10GE_NET_STATS_LEN      21
@@ -1880,14 +1805,6 @@ myri10ge_get_ethtool_stats(struct net_device *netdev,
                 data[i++] = (unsigned int)ss->tx.wake_queue;
                 data[i++] = (unsigned int)ss->tx.stop_queue;
                 data[i++] = (unsigned int)ss->tx.linearized;
-                data[i++] = ss->rx_done.lro_mgr.stats.aggregated;
-                data[i++] = ss->rx_done.lro_mgr.stats.flushed;
-                if (ss->rx_done.lro_mgr.stats.flushed)
-                        data[i++] = ss->rx_done.lro_mgr.stats.aggregated /
-                            ss->rx_done.lro_mgr.stats.flushed;
-                else
-                        data[i++] = 0;
-                data[i++] = ss->rx_done.lro_mgr.stats.no_desc;
         }
 }
 
@@ -2271,67 +2188,6 @@ static void myri10ge_free_irq(struct myri10ge_priv *mgp)
                 pci_disable_msix(pdev);
 }
 
-static int
-myri10ge_get_frag_header(struct skb_frag_struct *frag, void **mac_hdr,
-                         void **ip_hdr, void **tcpudp_hdr,
-                         u64 * hdr_flags, void *priv)
-{
-        struct ethhdr *eh;
-        struct vlan_ethhdr *veh;
-        struct iphdr *iph;
-        u8 *va = skb_frag_address(frag);
-        unsigned long ll_hlen;
-        /* passed opaque through lro_receive_frags() */
-        __wsum csum = (__force __wsum) (unsigned long)priv;
-
-        /* find the mac header, aborting if not IPv4 */
-
-        eh = (struct ethhdr *)va;
-        *mac_hdr = eh;
-        ll_hlen = ETH_HLEN;
-        if (eh->h_proto != htons(ETH_P_IP)) {
-                if (eh->h_proto == htons(ETH_P_8021Q)) {
-                        veh = (struct vlan_ethhdr *)va;
-                        if (veh->h_vlan_encapsulated_proto != htons(ETH_P_IP))
-                                return -1;
-
-                        ll_hlen += VLAN_HLEN;
-
-                        /*
-                         *  HW checksum starts ETH_HLEN bytes into
-                         *  frame, so we must subtract off the VLAN
-                         *  header's checksum before csum can be used
-                         */
-                        csum = csum_sub(csum, csum_partial(va + ETH_HLEN,
-                                                           VLAN_HLEN, 0));
-                } else {
-                        return -1;
-                }
-        }
-        *hdr_flags = LRO_IPV4;
-
-        iph = (struct iphdr *)(va + ll_hlen);
-        *ip_hdr = iph;
-        if (iph->protocol != IPPROTO_TCP)
-                return -1;
-        if (ip_is_fragment(iph))
-                return -1;
-        *hdr_flags |= LRO_TCP;
-        *tcpudp_hdr = (u8 *) (*ip_hdr) + (iph->ihl << 2);
-
-        /* verify the IP checksum */
-        if (unlikely(ip_fast_csum((u8 *) iph, iph->ihl)))
-                return -1;
-
-        /* verify the  checksum */
-        if (unlikely(csum_tcpudp_magic(iph->saddr, iph->daddr,
-                                       ntohs(iph->tot_len) - (iph->ihl << 2),
-                                       IPPROTO_TCP, csum)))
-                return -1;
-
-        return 0;
-}
-
 static int myri10ge_get_txrx(struct myri10ge_priv *mgp, int slice)
 {
         struct myri10ge_cmd cmd;
@@ -2402,7 +2258,6 @@ static int myri10ge_open(struct net_device *dev)
         struct myri10ge_cmd cmd;
         int i, status, big_pow2, slice;
         u8 *itable;
-        struct net_lro_mgr *lro_mgr;
 
         if (mgp->running != MYRI10GE_ETH_STOPPED)
                 return -EBUSY;
@@ -2513,19 +2368,6 @@ static int myri10ge_open(struct net_device *dev)
                         goto abort_with_rings;
                 }
 
-                lro_mgr = &ss->rx_done.lro_mgr;
-                lro_mgr->dev = dev;
-                lro_mgr->features = LRO_F_NAPI;
-                lro_mgr->ip_summed = CHECKSUM_COMPLETE;
-                lro_mgr->ip_summed_aggr = CHECKSUM_UNNECESSARY;
-                lro_mgr->max_desc = MYRI10GE_MAX_LRO_DESCRIPTORS;
-                lro_mgr->lro_arr = ss->rx_done.lro_desc;
-                lro_mgr->get_frag_header = myri10ge_get_frag_header;
-                lro_mgr->max_aggr = myri10ge_lro_max_pkts;
-                lro_mgr->frag_align_pad = 2;
-                if (lro_mgr->max_aggr > MAX_SKB_FRAGS)
-                        lro_mgr->max_aggr = MAX_SKB_FRAGS;
-
                 /* must happen prior to any irq */
                 napi_enable(&(ss)->napi);
         }
@@ -3143,15 +2985,6 @@ static int myri10ge_set_mac_address(struct net_device *dev, void *addr)
         return 0;
 }
 
-static netdev_features_t myri10ge_fix_features(struct net_device *dev,
-        netdev_features_t features)
-{
-        if (!(features & NETIF_F_RXCSUM))
-                features &= ~NETIF_F_LRO;
-
-        return features;
-}
-
 static int myri10ge_change_mtu(struct net_device *dev, int new_mtu)
 {
         struct myri10ge_priv *mgp = netdev_priv(dev);
@@ -3878,7 +3711,6 @@ static const struct net_device_ops myri10ge_netdev_ops = {
         .ndo_get_stats64        = myri10ge_get_stats,
         .ndo_validate_addr      = eth_validate_addr,
         .ndo_change_mtu         = myri10ge_change_mtu,
-        .ndo_fix_features       = myri10ge_fix_features,
         .ndo_set_rx_mode        = myri10ge_set_multicast_list,
         .ndo_set_mac_address    = myri10ge_set_mac_address,
 };
@@ -4018,7 +3850,7 @@ static int myri10ge_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
         netdev->netdev_ops = &myri10ge_netdev_ops;
         netdev->mtu = myri10ge_initial_mtu;
-        netdev->hw_features = mgp->features | NETIF_F_LRO | NETIF_F_RXCSUM;
+        netdev->hw_features = mgp->features | NETIF_F_RXCSUM;
         netdev->features = netdev->hw_features;
 
         if (dac_enabled)