pve-kernel-lowlatency-qoup/patches/kernel/0017-Revert-gro-add-support-of-hw-gro-packets-to-gro-stac.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Thomas Lamprecht <t.lamprecht@proxmox.com>
Date: Sat, 7 Jan 2023 13:50:22 +0100
Subject: [PATCH] Revert "gro: add support of (hw)gro packets to gro stack"

Seems to be the cause of a regression in network performance:
https://lore.kernel.org/netdev/CAK8fFZ5pzMaw3U1KXgC_OK4shKGsN=HDcR62cfPOuL0umXE1Ww@mail.gmail.com/

This reverts commit 5eddb24901ee49eee23c0bfce6af2e83fd5679bd.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
 net/core/gro.c         | 18 ++++--------------
 net/ipv4/tcp_offload.c | 17 ++---------------
 2 files changed, 6 insertions(+), 29 deletions(-)

diff --git a/net/core/gro.c b/net/core/gro.c
index bc9451743307..b4190eb08467 100644
--- a/net/core/gro.c
+++ b/net/core/gro.c
@@ -160,7 +160,6 @@ int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb)
 	unsigned int gro_max_size;
 	unsigned int new_truesize;
 	struct sk_buff *lp;
-	int segs;
 
 	/* pairs with WRITE_ONCE() in netif_set_gro_max_size() */
 	gro_max_size = READ_ONCE(p->dev->gro_max_size);
@@ -176,7 +175,6 @@ int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb)
 			return -E2BIG;
 	}
 
-	segs = NAPI_GRO_CB(skb)->count;
 	lp = NAPI_GRO_CB(p)->last;
 	pinfo = skb_shinfo(lp);
 
@@ -267,7 +265,7 @@ int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb)
 	lp = p;
 
 done:
-	NAPI_GRO_CB(p)->count += segs;
+	NAPI_GRO_CB(p)->count++;
 	p->data_len += len;
 	p->truesize += delta_truesize;
 	p->len += len;
@@ -498,15 +496,8 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
 		BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct napi_gro_cb, zeroed),
 					 sizeof(u32))); /* Avoid slow unaligned acc */
 		*(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0;
-		NAPI_GRO_CB(skb)->flush = skb_has_frag_list(skb);
+		NAPI_GRO_CB(skb)->flush = skb_is_gso(skb) || skb_has_frag_list(skb);
 		NAPI_GRO_CB(skb)->is_atomic = 1;
-		NAPI_GRO_CB(skb)->count = 1;
-		if (unlikely(skb_is_gso(skb))) {
-			NAPI_GRO_CB(skb)->count = skb_shinfo(skb)->gso_segs;
-			/* Only support TCP at the moment. */
-			if (!skb_is_gso_tcp(skb))
-				NAPI_GRO_CB(skb)->flush = 1;
-		}
 
 		/* Setup for GRO checksum validation */
 		switch (skb->ip_summed) {
@@ -554,10 +545,10 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
 	else
 		gro_list->count++;
 
+	NAPI_GRO_CB(skb)->count = 1;
 	NAPI_GRO_CB(skb)->age = jiffies;
 	NAPI_GRO_CB(skb)->last = skb;
-	if (!skb_is_gso(skb))
-		skb_shinfo(skb)->gso_size = skb_gro_len(skb);
+	skb_shinfo(skb)->gso_size = skb_gro_len(skb);
 	list_add(&skb->list, &gro_list->list);
 	ret = GRO_HELD;
 
@@ -669,7 +660,6 @@ static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb)
 
 	skb->encapsulation = 0;
 	skb_shinfo(skb)->gso_type = 0;
-	skb_shinfo(skb)->gso_size = 0;
 	if (unlikely(skb->slow_gro)) {
 		skb_orphan(skb);
 		skb_ext_reset(skb);
diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c
index 45dda7889387..a844a0d38482 100644
--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -255,15 +255,7 @@ struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb)
 
 	mss = skb_shinfo(p)->gso_size;
 
-	/* If skb is a GRO packet, make sure its gso_size matches prior packet mss.
-	 * If it is a single frame, do not aggregate it if its length
-	 * is bigger than our mss.
-	 */
-	if (unlikely(skb_is_gso(skb)))
-		flush |= (mss != skb_shinfo(skb)->gso_size);
-	else
-		flush |= (len - 1) >= mss;
-
+	flush |= (len - 1) >= mss;
 	flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
 #ifdef CONFIG_TLS_DEVICE
 	flush |= p->decrypted ^ skb->decrypted;
@@ -277,12 +269,7 @@ struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb)
 	tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);
 
 out_check_final:
-	/* Force a flush if last segment is smaller than mss. */
-	if (unlikely(skb_is_gso(skb)))
-		flush = len != NAPI_GRO_CB(skb)->count * skb_shinfo(skb)->gso_size;
-	else
-		flush = len < mss;
-
+	flush = len < mss;
 	flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
 					TCP_FLAG_RST | TCP_FLAG_SYN |
 					TCP_FLAG_FIN));