[I/OAT]: TCP recv offload to I/OAT

Locks down user pages and sets up for DMA in tcp_recvmsg, then calls
dma_async_try_early_copy in tcp_v4_do_rcv

Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 4e067d2..ff6ccda 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -263,7 +263,7 @@
 #include <net/tcp.h>
 #include <net/xfrm.h>
 #include <net/ip.h>
-
+#include <net/netdma.h>
 
 #include <asm/uaccess.h>
 #include <asm/ioctls.h>
@@ -1110,6 +1110,7 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
        int target;             /* Read at least this many bytes */
        long timeo;
        struct task_struct *user_recv = NULL;
+       int copied_early = 0;
 
        lock_sock(sk);
 
@@ -1133,6 +1134,17 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 
        target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
 
+#ifdef CONFIG_NET_DMA
+       tp->ucopy.dma_chan = NULL;
+       preempt_disable();
+       if ((len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
+           !sysctl_tcp_low_latency && __get_cpu_var(softnet_data.net_dma)) {
+               preempt_enable_no_resched();
+               tp->ucopy.pinned_list = dma_pin_iovec_pages(msg->msg_iov, len);
+       } else
+               preempt_enable_no_resched();
+#endif
+
        do {
                struct sk_buff *skb;
                u32 offset;
@@ -1274,6 +1286,10 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
                } else
                        sk_wait_data(sk, &timeo);
 
+#ifdef CONFIG_NET_DMA
+               tp->ucopy.wakeup = 0;
+#endif
+
                if (user_recv) {
                        int chunk;
 
@@ -1329,13 +1345,39 @@ do_prequeue:
                }
 
                if (!(flags & MSG_TRUNC)) {
-                       err = skb_copy_datagram_iovec(skb, offset,
-                                                     msg->msg_iov, used);
-                       if (err) {
-                               /* Exception. Bailout! */
-                               if (!copied)
-                                       copied = -EFAULT;
-                               break;
+#ifdef CONFIG_NET_DMA
+                       if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
+                               tp->ucopy.dma_chan = get_softnet_dma();
+
+                       if (tp->ucopy.dma_chan) {
+                               tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
+                                       tp->ucopy.dma_chan, skb, offset,
+                                       msg->msg_iov, used,
+                                       tp->ucopy.pinned_list);
+
+                               if (tp->ucopy.dma_cookie < 0) {
+
+                                       printk(KERN_ALERT "dma_cookie < 0\n");
+
+                                       /* Exception. Bailout! */
+                                       if (!copied)
+                                               copied = -EFAULT;
+                                       break;
+                               }
+                               if ((offset + used) == skb->len)
+                                       copied_early = 1;
+
+                       } else
+#endif
+                       {
+                               err = skb_copy_datagram_iovec(skb, offset,
+                                               msg->msg_iov, used);
+                               if (err) {
+                                       /* Exception. Bailout! */
+                                       if (!copied)
+                                               copied = -EFAULT;
+                                       break;
+                               }
                        }
                }
 
@@ -1355,15 +1397,19 @@ skip_copy:
 
                if (skb->h.th->fin)
                        goto found_fin_ok;
-               if (!(flags & MSG_PEEK))
-                       sk_eat_skb(sk, skb, 0);
+               if (!(flags & MSG_PEEK)) {
+                       sk_eat_skb(sk, skb, copied_early);
+                       copied_early = 0;
+               }
                continue;
 
        found_fin_ok:
                /* Process the FIN. */
                ++*seq;
-               if (!(flags & MSG_PEEK))
-                       sk_eat_skb(sk, skb, 0);
+               if (!(flags & MSG_PEEK)) {
+                       sk_eat_skb(sk, skb, copied_early);
+                       copied_early = 0;
+               }
                break;
        } while (len > 0);
 
@@ -1386,6 +1432,36 @@ skip_copy:
                tp->ucopy.len = 0;
        }
 
+#ifdef CONFIG_NET_DMA
+       if (tp->ucopy.dma_chan) {
+               struct sk_buff *skb;
+               dma_cookie_t done, used;
+
+               dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
+
+               while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
+                                                tp->ucopy.dma_cookie, &done,
+                                                &used) == DMA_IN_PROGRESS) {
+                       /* do partial cleanup of sk_async_wait_queue */
+                       while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
+                              (dma_async_is_complete(skb->dma_cookie, done,
+                                                     used) == DMA_SUCCESS)) {
+                               __skb_dequeue(&sk->sk_async_wait_queue);
+                               kfree_skb(skb);
+                       }
+               }
+
+               /* Safe to free early-copied skbs now */
+               __skb_queue_purge(&sk->sk_async_wait_queue);
+               dma_chan_put(tp->ucopy.dma_chan);
+               tp->ucopy.dma_chan = NULL;
+       }
+       if (tp->ucopy.pinned_list) {
+               dma_unpin_iovec_pages(tp->ucopy.pinned_list);
+               tp->ucopy.pinned_list = NULL;
+       }
+#endif
+
        /* According to UNIX98, msg_name/msg_namelen are ignored
         * on connected socket. I was just happy when found this 8) --ANK
         */
@@ -1658,6 +1734,9 @@ int tcp_disconnect(struct sock *sk, int flags)
        __skb_queue_purge(&sk->sk_receive_queue);
        sk_stream_writequeue_purge(sk);
        __skb_queue_purge(&tp->out_of_order_queue);
+#ifdef CONFIG_NET_DMA
+       __skb_queue_purge(&sk->sk_async_wait_queue);
+#endif
 
        inet->dport = 0;
 

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index b5521a9..c6d62f0 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -71,6 +71,7 @@
 #include <net/inet_common.h>
 #include <linux/ipsec.h>
 #include <asm/unaligned.h>
+#include <net/netdma.h>
 
 int sysctl_tcp_timestamps = 1;
 int sysctl_tcp_window_scaling = 1;
@@ -3785,6 +3786,50 @@ static inline int tcp_checksum_complete_user(struct sock *sk, struct sk_buff *sk
                __tcp_checksum_complete_user(sk, skb);
 }
 
+#ifdef CONFIG_NET_DMA
+static int tcp_dma_try_early_copy(struct sock *sk, struct sk_buff *skb, int hlen)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       int chunk = skb->len - hlen;
+       int dma_cookie;
+       int copied_early = 0;
+
+       if (tp->ucopy.wakeup)
+               return 0;
+
+       if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
+               tp->ucopy.dma_chan = get_softnet_dma();
+
+       if (tp->ucopy.dma_chan && skb->ip_summed == CHECKSUM_UNNECESSARY) {
+
+               dma_cookie = dma_skb_copy_datagram_iovec(tp->ucopy.dma_chan,
+                       skb, hlen, tp->ucopy.iov, chunk, tp->ucopy.pinned_list);
+
+               if (dma_cookie < 0)
+                       goto out;
+
+               tp->ucopy.dma_cookie = dma_cookie;
+               copied_early = 1;
+
+               tp->ucopy.len -= chunk;
+               tp->copied_seq += chunk;
+               tcp_rcv_space_adjust(sk);
+
+               if ((tp->ucopy.len == 0) ||
+                   (tcp_flag_word(skb->h.th) & TCP_FLAG_PSH) ||
+                   (atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1))) {
+                       tp->ucopy.wakeup = 1;
+                       sk->sk_data_ready(sk, 0);
+               }
+       } else if (chunk > 0) {
+               tp->ucopy.wakeup = 1;
+               sk->sk_data_ready(sk, 0);
+       }
+out:
+       return copied_early;
+}
+#endif /* CONFIG_NET_DMA */
+
 /*
  *     TCP receive function for the ESTABLISHED state. 
  *
@@ -3901,14 +3946,23 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
                        }
                } else {
                        int eaten = 0;
+                       int copied_early = 0;
 
-                       if (tp->ucopy.task == current &&
-                           tp->copied_seq == tp->rcv_nxt &&
-                           len - tcp_header_len <= tp->ucopy.len &&
-                           sock_owned_by_user(sk)) {
-                               __set_current_state(TASK_RUNNING);
+                       if (tp->copied_seq == tp->rcv_nxt &&
+                           len - tcp_header_len <= tp->ucopy.len) {
+#ifdef CONFIG_NET_DMA
+                               if (tcp_dma_try_early_copy(sk, skb, tcp_header_len)) {
+                                       copied_early = 1;
+                                       eaten = 1;
+                               }
+#endif
+                               if (tp->ucopy.task == current && sock_owned_by_user(sk) && !copied_early) {
+                                       __set_current_state(TASK_RUNNING);
 
-                               if (!tcp_copy_to_iovec(sk, skb, tcp_header_len)) {
+                                       if (!tcp_copy_to_iovec(sk, skb, tcp_header_len))
+                                               eaten = 1;
+                               }
+                               if (eaten) {
                                        /* Predicted packet is in window by definition.
                                         * seq == rcv_nxt and rcv_wup <= rcv_nxt.
                                         * Hence, check seq<=rcv_wup reduces to:
@@ -3924,8 +3978,9 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
                                        __skb_pull(skb, tcp_header_len);
                                        tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
                                        NET_INC_STATS_BH(LINUX_MIB_TCPHPHITSTOUSER);
-                                       eaten = 1;
                                }
+                               if (copied_early)
+                                       tcp_cleanup_rbuf(sk, skb->len);
                        }
                        if (!eaten) {
                                if (tcp_checksum_complete_user(sk, skb))
@@ -3966,6 +4021,11 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
 
                        __tcp_ack_snd_check(sk, 0);
 no_ack:
+#ifdef CONFIG_NET_DMA
+                       if (copied_early)
+                               __skb_queue_tail(&sk->sk_async_wait_queue, skb);
+                       else
+#endif
                        if (eaten)
                                __kfree_skb(skb);
                        else

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 672950e..25ecc6e 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -71,6 +71,7 @@
 #include <net/inet_common.h>
 #include <net/timewait_sock.h>
 #include <net/xfrm.h>
+#include <net/netdma.h>
 
 #include <linux/inet.h>
 #include <linux/ipv6.h>
@@ -1091,8 +1092,18 @@ process:
        bh_lock_sock(sk);
        ret = 0;
        if (!sock_owned_by_user(sk)) {
-               if (!tcp_prequeue(sk, skb))
+#ifdef CONFIG_NET_DMA
+               struct tcp_sock *tp = tcp_sk(sk);
+               if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
+                       tp->ucopy.dma_chan = get_softnet_dma();
+               if (tp->ucopy.dma_chan)
                        ret = tcp_v4_do_rcv(sk, skb);
+               else
+#endif
+               {
+                       if (!tcp_prequeue(sk, skb))
+                       ret = tcp_v4_do_rcv(sk, skb);
+               }
        } else
                sk_add_backlog(sk, skb);
        bh_unlock_sock(sk);
@@ -1296,6 +1307,11 @@ int tcp_v4_destroy_sock(struct sock *sk)
        /* Cleans up our, hopefully empty, out_of_order_queue. */
        __skb_queue_purge(&tp->out_of_order_queue);
 
+#ifdef CONFIG_NET_DMA
+       /* Cleans up our sk_async_wait_queue */
+       __skb_queue_purge(&sk->sk_async_wait_queue);
+#endif
+
        /* Clean prequeue, it must be empty really */
        __skb_queue_purge(&tp->ucopy.prequeue);
 

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 301eee7..a50eb30 100644 (file)
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1218,8 +1218,16 @@ process:
        bh_lock_sock(sk);
        ret = 0;
        if (!sock_owned_by_user(sk)) {
-               if (!tcp_prequeue(sk, skb))
-                       ret = tcp_v6_do_rcv(sk, skb);
+#ifdef CONFIG_NET_DMA
+                struct tcp_sock *tp = tcp_sk(sk);
+                if (tp->ucopy.dma_chan)
+                        ret = tcp_v6_do_rcv(sk, skb);
+                else
+#endif
+               {
+                       if (!tcp_prequeue(sk, skb))
+                               ret = tcp_v6_do_rcv(sk, skb);
+               }
        } else
                sk_add_backlog(sk, skb);
        bh_unlock_sock(sk);