[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
--- 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 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 @@
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 @@
} else
sk_wait_data(sk, &timeo);
+#ifdef CONFIG_NET_DMA
+ tp->ucopy.wakeup = 0;
+#endif
+
if (user_recv) {
int chunk;
@@ -1329,13 +1345,39 @@
}
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 @@
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 @@
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 @@
__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;