tcp: don't split packets for restoring a send queue

The kernel can do it better. The problem exists only for recv queues.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

include/kerndat.h

@@ -16,7 +16,6 @@ extern int kerndat_get_dirty_track(void);
 
 struct kerndat_s {
 	dev_t shmem_dev;
-	int tcp_max_wshare;
 	int tcp_max_rshare;
 	int last_cap;
 	u64 zero_page_pfn;

kerndat.c

@@ -19,7 +19,6 @@
 #include "util.h"
 
 struct kerndat_s kdat = {
-	.tcp_max_wshare = 2U << 20,
 	.tcp_max_rshare = 3U << 20,
 };
 
@@ -197,7 +196,6 @@ static int tcp_read_sysctl_limits(void)
 	int ret;
 
 	struct sysctl_req req[] = {
-		{ "net/ipv4/tcp_wmem", &vect[0], CTL_U32A(ARRAY_SIZE(vect[0])) },
 		{ "net/ipv4/tcp_rmem", &vect[1], CTL_U32A(ARRAY_SIZE(vect[1])) },
 		{ },
 	};
@@ -212,13 +210,12 @@ static int tcp_read_sysctl_limits(void)
 		goto out;
 	}
 
-	kdat.tcp_max_wshare = min(kdat.tcp_max_wshare, (int)vect[0][2]);
 	kdat.tcp_max_rshare = min(kdat.tcp_max_rshare, (int)vect[1][2]);
 
-	if (kdat.tcp_max_wshare < 128 || kdat.tcp_max_rshare < 128)
+	if (kdat.tcp_max_rshare < 128)
 		pr_warn("The memory limits for TCP queues are suspiciously small\n");
 out:
-	pr_debug("TCP queue memory limits are %d:%d\n", kdat.tcp_max_wshare, kdat.tcp_max_rshare);
+	pr_debug("TCP recv queue memory limit is %d\n", kdat.tcp_max_rshare);
 	return 0;
 }
 

sk-tcp.c

@@ -456,7 +456,7 @@ static int restore_tcp_seqs(int sk, TcpStreamEntry *tse)
 static int __send_tcp_queue(int sk, int queue, u32 len, struct cr_img *img)
 {
 	int ret, err = -1;
-	int off, max;
+	int off;
 	char *buf;
 
 	buf = xmalloc(len);
@@ -466,10 +466,12 @@ static int __send_tcp_queue(int sk, int queue, u32 len, struct cr_img *img)
 	if (read_img_buf(img, buf, len) < 0)
 		goto err;
 
-	max = (queue == TCP_SEND_QUEUE) ? kdat.tcp_max_wshare : kdat.tcp_max_rshare;
 	off = 0;
 	while (len) {
-		int chunk = (len > max ? max : len);
+		int chunk = len;
+
+		if (queue == TCP_RECV_QUEUE && len > kdat.tcp_max_rshare)
+			chunk = kdat.tcp_max_rshare;
 
 		ret = send(sk, buf + off, chunk, 0);
 		if (ret <= 0) {