From 6eee6b8bd1ce6cd43b19a0748e249ce2eac6ca15 Mon Sep 17 00:00:00 2001
From: Stefan Lankes <slankes@eonerc.rwth-aachen.de>
Date: Mon, 6 Aug 2018 07:54:34 +0200
Subject: [PATCH] remove obsolete buffering of TX packets

---
 caves                   |  2 +-
 drivers/net/uhyve-net.c | 38 +++-----------------------------------
 drivers/net/uhyve-net.h |  8 +-------
 3 files changed, 5 insertions(+), 43 deletions(-)

diff --git a/caves b/caves
index 2a7238cc6..7c7b47f8e 160000
--- a/caves
+++ b/caves
@@ -1 +1 @@
-Subproject commit 2a7238cc66cf35ac4d67ea7b66d0d24ba94e01c2
+Subproject commit 7c7b47f8e251b09302ed43c18ffcf639d4c0a118
diff --git a/drivers/net/uhyve-net.c b/drivers/net/uhyve-net.c
index f82e46c0e..d77760eed 100755
--- a/drivers/net/uhyve-net.c
+++ b/drivers/net/uhyve-net.c
@@ -125,29 +125,14 @@ static inline uint8_t dehex(char c)
 
 static err_t uhyve_netif_output(struct netif* netif, struct pbuf* p)
 {
-	uhyve_netif_t* uhyve_netif = netif->state;
-	uint8_t transmitid = uhyve_netif->tx_queue % TX_BUF_NUM;
 	uint32_t i;
 	struct pbuf *q;
 
-	if(BUILTIN_EXPECT((uhyve_netif->tx_queue - uhyve_netif->tx_complete) > (TX_BUF_NUM - 1), 0)) {
-		LOG_ERROR("uhyve_netif_output: too many packets at once\n");
-		return ERR_IF;
-	}
-
 	if(BUILTIN_EXPECT(p->tot_len > 1792, 0)) {
 		LOG_ERROR("uhyve_netif_output: packet (%i bytes) is longer than 1792 bytes\n", p->tot_len);
 		return ERR_IF;
 	}
 
-	if(uhyve_netif->tx_inuse[transmitid] == 1) {
-		LOG_ERROR("uhyve_netif_output: %i already inuse\n", transmitid);
-		return ERR_IF;
-	}
-
-	uhyve_netif->tx_queue++;
-	uhyve_netif->tx_inuse[transmitid] = 1;
-
 #if ETH_PAD_SIZE
 	pbuf_header(p, -ETH_PAD_SIZE); /*drop padding word */
 #endif
@@ -157,11 +142,10 @@ static err_t uhyve_netif_output(struct netif* netif, struct pbuf* p)
 	 * This list MUST consist of a single packet ONLY
 	 */
 	for (q = p, i = 0; q != 0; q = q->next) {
-		memcpy(uhyve_netif->tx_buf[transmitid] + i, q->payload, q->len);
+		// send the packet
+		uhyve_net_write_sync(q->payload, q->len);
 		i += q->len;
 	}
-	// send the packet
-	uhyve_net_write_sync(uhyve_netif->tx_buf[transmitid], p->tot_len);
 
 #if ETH_PAD_SIZE
 	pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */
@@ -169,10 +153,6 @@ static err_t uhyve_netif_output(struct netif* netif, struct pbuf* p)
 
 	LINK_STATS_INC(link.xmit);
 
-	uhyve_netif->tx_complete++;
-	uhyve_netif->tx_inuse[transmitid] = 0;
-//	LOG_INFO("Transmit OK | queue = %i, complete = %i \n", uhyve_netif->tx_queue, uhyve_netif->tx_complete);
-
 	return ERR_OK;
 }
 
@@ -259,18 +239,6 @@ err_t uhyve_netif_init (struct netif* netif)
 	}
 	memset(uhyve_netif->rx_buf, 0x00, RX_BUF_LEN + 16);
 
-	uhyve_netif->tx_buf[0] = page_alloc(TX_BUF_NUM * TX_BUF_LEN, VMA_READ|VMA_WRITE|VMA_CACHEABLE);
-	if (!(uhyve_netif->tx_buf[0])) {
-		LOG_ERROR("uhyve_netif_init: out of memory\n");
-		page_free(uhyve_netif->rx_buf, RX_BUF_LEN + 16);
-		kfree(uhyve_netif);
-		return ERR_MEM;
-	}
-	memset(uhyve_netif->tx_buf[0], 0x00, TX_BUF_NUM * TX_BUF_LEN);
-	for (int i = 1; i < TX_BUF_NUM; i++) {
-		uhyve_netif->tx_buf[i] = uhyve_netif->tx_buf[0] + i*TX_BUF_LEN;
-	}
-
 	netif->state = uhyve_netif;
 	mynetif = netif;
 
@@ -306,7 +274,7 @@ err_t uhyve_netif_init (struct netif* netif)
 	netif->output = etharp_output;
 	netif->linkoutput = uhyve_netif_output;
 	/* maximum transfer unit */
-	netif->mtu = 1500;
+	netif->mtu = 32768;
 	/* broadcast capability */
 	netif->flags |= NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_IGMP | NETIF_FLAG_LINK_UP | NETIF_FLAG_MLD6;
 
diff --git a/drivers/net/uhyve-net.h b/drivers/net/uhyve-net.h
index c031f0d30..4991752b1 100755
--- a/drivers/net/uhyve-net.h
+++ b/drivers/net/uhyve-net.h
@@ -35,9 +35,7 @@
 
 #define MIN(a, b)	(a) < (b) ? (a) : (b)
 
-#define RX_BUF_LEN 2048
-#define TX_BUF_LEN 2048
-#define TX_BUF_NUM 1		//number of tx buffer
+#define RX_BUF_LEN 3276
 
 // UHYVE_PORT_NETINFO
 typedef struct {
@@ -77,10 +75,6 @@ typedef struct {
 typedef struct uhyve_netif {
 	struct eth_addr *ethaddr;
 	/* Add whatever per-interface state that is needed here. */
-	uint8_t* tx_buf[TX_BUF_NUM];
-	uint32_t tx_queue;
-	uint32_t tx_complete;
-	uint8_t tx_inuse[TX_BUF_NUM];
 	uint8_t* rx_buf;
 } uhyve_netif_t;