net_dma: simple removal

Per commit "77873803363c net_dma: mark broken" net_dma is no longer used
and there is no plan to fix it.

This is the mechanical removal of bits in CONFIG_NET_DMA ifdef guards.
Reverting the remainder of the net_dma induced changes is deferred to
subsequent patches.

Marked for stable due to Roman's report of a memory leak in
dma_pin_iovec_pages():

    https://lkml.org/lkml/2014/9/3/177

Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: David Whipple <whipple@securedatainnovations.ch>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: <stable@vger.kernel.org>
Reported-by: Roman Gushchin <klamm@yandex-team.ru>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 14 insertions, 133 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 97c8f5620c43..28595a364f09 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -274,7 +274,6 @@
 #include <net/tcp.h>
 #include <net/xfrm.h>
 #include <net/ip.h>
-#include <net/netdma.h>
 #include <net/sock.h>
 
 #include <asm/uaccess.h>
@@ -1454,39 +1453,6 @@ static void tcp_prequeue_process(struct sock *sk)
         tp->ucopy.memory = 0;
 }
 
-#ifdef CONFIG_NET_DMA
-static void tcp_service_net_dma(struct sock *sk, bool wait)
-{
-        dma_cookie_t done, used;
-        dma_cookie_t last_issued;
-        struct tcp_sock *tp = tcp_sk(sk);
-
-        if (!tp->ucopy.dma_chan)
-                return;
-
-        last_issued = tp->ucopy.dma_cookie;
-        dma_async_issue_pending(tp->ucopy.dma_chan);
-
-        do {
-                if (dma_async_is_tx_complete(tp->ucopy.dma_chan,
-                                              last_issued, &done,
-                                              &used) == DMA_COMPLETE) {
-                        /* Safe to free early-copied skbs now */
-                        __skb_queue_purge(&sk->sk_async_wait_queue);
-                        break;
-                } else {
-                        struct sk_buff *skb;
-                        while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
-                               (dma_async_is_complete(skb->dma_cookie, done,
-                                                      used) == DMA_COMPLETE)) {
-                                __skb_dequeue(&sk->sk_async_wait_queue);
-                                kfree_skb(skb);
-                        }
-                }
-        } while (wait);
-}
-#endif
-
 static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
 {
         struct sk_buff *skb;
@@ -1504,7 +1470,7 @@ static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
                  * splitted a fat GRO packet, while we released socket lock
                  * in skb_splice_bits()
                  */
-                sk_eat_skb(sk, skb, false);
+                sk_eat_skb(sk, skb);
         }
         return NULL;
 }
@@ -1570,11 +1536,11 @@ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
                                 continue;
                 }
                 if (tcp_hdr(skb)->fin) {
-                        sk_eat_skb(sk, skb, false);
+                        sk_eat_skb(sk, skb);
                         ++seq;
                         break;
                 }
-                sk_eat_skb(sk, skb, false);
+                sk_eat_skb(sk, skb);
                 if (!desc->count)
                         break;
                 tp->copied_seq = seq;
@@ -1612,7 +1578,6 @@ 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;
-        bool copied_early = false;
         struct sk_buff *skb;
         u32 urg_hole = 0;
 
@@ -1655,28 +1620,6 @@ 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();
-        skb = skb_peek_tail(&sk->sk_receive_queue);
-        {
-                int available = 0;
-
-                if (skb)
-                        available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
-                if ((available < target) &&
-                    (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
-                    !sysctl_tcp_low_latency &&
-                    net_dma_find_channel()) {
-                        preempt_enable();
-                        tp->ucopy.pinned_list =
-                                        dma_pin_iovec_pages(msg->msg_iov, len);
-                } else {
-                        preempt_enable();
-                }
-        }
-#endif
-
         do {
                 u32 offset;
 
@@ -1807,16 +1750,6 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
                         /* __ Set realtime policy in scheduler __ */
                 }
 
-#ifdef CONFIG_NET_DMA
-                if (tp->ucopy.dma_chan) {
-                        if (tp->rcv_wnd == 0 &&
-                            !skb_queue_empty(&sk->sk_async_wait_queue)) {
-                                tcp_service_net_dma(sk, true);
-                                tcp_cleanup_rbuf(sk, copied);
-                        } else
-                                dma_async_issue_pending(tp->ucopy.dma_chan);
-                }
-#endif
                 if (copied >= target) {
                         /* Do not sleep, just process backlog. */
                         release_sock(sk);
@@ -1824,11 +1757,6 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
                 } else
                         sk_wait_data(sk, &timeo);
 
-#ifdef CONFIG_NET_DMA
-                tcp_service_net_dma(sk, false);  /* Don't block */
-                tp->ucopy.wakeup = 0;
-#endif
-
                 if (user_recv) {
                         int chunk;
 
@@ -1886,43 +1814,13 @@ do_prequeue:
                 }
 
                 if (!(flags & MSG_TRUNC)) {
-#ifdef CONFIG_NET_DMA
-                        if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
-                                tp->ucopy.dma_chan = net_dma_find_channel();
-
-                        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) {
-
-                                        pr_alert("%s: dma_cookie < 0\n",
-                                                 __func__);
-
-                                        /* Exception. Bailout! */
-                                        if (!copied)
-                                                copied = -EFAULT;
-                                        break;
-                                }
-
-                                dma_async_issue_pending(tp->ucopy.dma_chan);
-
-                                if ((offset + used) == skb->len)
-                                        copied_early = true;
-
-                        } else
-#endif
-                        {
-                                err = skb_copy_datagram_iovec(skb, offset,
-                                                msg->msg_iov, used);
-                                if (err) {
-                                        /* Exception. Bailout! */
-                                        if (!copied)
-                                                copied = -EFAULT;
-                                        break;
-                                }
+                        err = skb_copy_datagram_iovec(skb, offset,
+                                                      msg->msg_iov, used);
+                        if (err) {
+                                /* Exception. Bailout! */
+                                if (!copied)
+                                        copied = -EFAULT;
+                                break;
                         }
                 }
 
@@ -1942,19 +1840,15 @@ skip_copy:
 
                 if (tcp_hdr(skb)->fin)
                         goto found_fin_ok;
-                if (!(flags & MSG_PEEK)) {
-                        sk_eat_skb(sk, skb, copied_early);
-                        copied_early = false;
-                }
+                if (!(flags & MSG_PEEK))
+                        sk_eat_skb(sk, skb);
                 continue;
 
         found_fin_ok:
                 /* Process the FIN. */
                 ++*seq;
-                if (!(flags & MSG_PEEK)) {
-                        sk_eat_skb(sk, skb, copied_early);
-                        copied_early = false;
-                }
+                if (!(flags & MSG_PEEK))
+                        sk_eat_skb(sk, skb);
                 break;
         } while (len > 0);
 
@@ -1977,16 +1871,6 @@ skip_copy:
                 tp->ucopy.len = 0;
         }
 
-#ifdef CONFIG_NET_DMA
-        tcp_service_net_dma(sk, true);  /* Wait for queue to drain */
-        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
          */
@@ -2330,9 +2214,6 @@ int tcp_disconnect(struct sock *sk, int flags)
         __skb_queue_purge(&sk->sk_receive_queue);
         tcp_write_queue_purge(sk);
         __skb_queue_purge(&tp->out_of_order_queue);
-#ifdef CONFIG_NET_DMA
-        __skb_queue_purge(&sk->sk_async_wait_queue);
-#endif
 
         inet->inet_dport = 0;