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>

4 files changed, 15 insertions, 220 deletions

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 44eba052b43d..c3d2a48481f1 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -635,15 +635,6 @@ static struct ctl_table ipv4_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec
 	},
-#ifdef CONFIG_NET_DMA
-	{
-		.procname	= "tcp_dma_copybreak",
-		.data		= &sysctl_tcp_dma_copybreak,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec
-	},
-#endif
 	{
 		.procname	= "tcp_slow_start_after_idle",
 		.data		= &sysctl_tcp_slow_start_after_idle,
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;
 
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index eeaac399420d..1342e9851f97 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -73,7 +73,6 @@
 #include <net/inet_common.h>
 #include <linux/ipsec.h>
 #include <asm/unaligned.h>
-#include <net/netdma.h>
 
 int sysctl_tcp_timestamps __read_mostly = 1;
 int sysctl_tcp_window_scaling __read_mostly = 1;
@@ -4970,53 +4969,6 @@ static inline bool tcp_checksum_complete_user(struct sock *sk,
 	       __tcp_checksum_complete_user(sk, skb);
 }
 
-#ifdef CONFIG_NET_DMA
-static bool 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;
-	bool copied_early = false;
-
-	if (tp->ucopy.wakeup)
-		return false;
-
-	if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
-		tp->ucopy.dma_chan = net_dma_find_channel();
-
-	if (tp->ucopy.dma_chan && skb_csum_unnecessary(skb)) {
-
-		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 = true;
-
-		tp->ucopy.len -= chunk;
-		tp->copied_seq += chunk;
-		tcp_rcv_space_adjust(sk);
-
-		if ((tp->ucopy.len == 0) ||
-		    (tcp_flag_word(tcp_hdr(skb)) & 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 */
-
 /* Does PAWS and seqno based validation of an incoming segment, flags will
  * play significant role here.
  */
@@ -5201,14 +5153,6 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
 
 			if (tp->copied_seq == tp->rcv_nxt &&
 			    len - tcp_header_len <= tp->ucopy.len) {
-#ifdef CONFIG_NET_DMA
-				if (tp->ucopy.task == current &&
-				    sock_owned_by_user(sk) &&
-				    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);
@@ -5274,11 +5218,6 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
 			if (!copied_early || tp->rcv_nxt != tp->rcv_wup)
 				__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_partial(skb, fragstolen);
 			sk->sk_data_ready(sk, 0);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 3cf976510497..737c2e270ee3 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -72,7 +72,6 @@
 #include <net/inet_common.h>
 #include <net/timewait_sock.h>
 #include <net/xfrm.h>
-#include <net/netdma.h>
 #include <net/secure_seq.h>
 #include <net/tcp_memcontrol.h>
 #include <net/busy_poll.h>
@@ -1999,18 +1998,8 @@ process:
 	bh_lock_sock_nested(sk);
 	ret = 0;
 	if (!sock_owned_by_user(sk)) {
-#ifdef CONFIG_NET_DMA
-		struct tcp_sock *tp = tcp_sk(sk);
-		if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
-			tp->ucopy.dma_chan = net_dma_find_channel();
-		if (tp->ucopy.dma_chan)
+		if (!tcp_prequeue(sk, skb))
 			ret = tcp_v4_do_rcv(sk, skb);
-		else
-#endif
-		{
-			if (!tcp_prequeue(sk, skb))
-				ret = tcp_v4_do_rcv(sk, skb);
-		}
 	} else if (unlikely(sk_add_backlog(sk, skb,
 					   sk->sk_rcvbuf + sk->sk_sndbuf))) {
 		bh_unlock_sock(sk);
@@ -2169,11 +2158,6 @@ void tcp_v4_destroy_sock(struct sock *sk)
 	}
 #endif
 
-#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);