git: c9047eb7b30d - main - tcp: allow TSO even while RX path is unordered

The branch main has been updated by rscheff:

URL: https://cgit.FreeBSD.org/src/commit/?id=c9047eb7b30d8f88fd90b62fbb40d90e046bd1d7

commit c9047eb7b30d8f88fd90b62fbb40d90e046bd1d7
Author:     Richard Scheffenegger <rscheff@FreeBSD.org>
AuthorDate: 2024-11-14 07:38:30 +0000
Commit:     Richard Scheffenegger <rscheff@FreeBSD.org>
CommitDate: 2024-11-14 08:15:53 +0000

    tcp: allow TSO even while RX path is unordered
    
    Over IP networks, forward and return path largely
    act independently from each other. Do not disable LRO
    on the TX side, when reordering/loss is happening
    on the RX half-connection.
    
    Reviewed By: rrs, #transport, peter.lei_ieee.org
    Sponsored by: NetApp, Inc.
    Differential Revision: https://reviews.freebsd.org/D47056
---
 sys/netinet/tcp_output.c      | 8 ++++----
 sys/netinet/tcp_stacks/bbr.c  | 1 -
 sys/netinet/tcp_stacks/rack.c | 5 +----
 3 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c
index 8f19885f6b9b..38ce2e3f3145 100644
--- a/sys/netinet/tcp_output.c
+++ b/sys/netinet/tcp_output.c
@@ -513,8 +513,8 @@ after_sack_rexmit:
 	 * hardware).
 	 *
 	 * TSO may only be used if we are in a pure bulk sending state.  The
-	 * presence of TCP-MD5, SACK retransmits, SACK advertizements and
-	 * IP options prevent using TSO.  With TSO the TCP header is the same
+	 * presence of TCP-MD5, IP options (IPsec), and possibly SACK
+	 * retransmits prevent using TSO.  With TSO the TCP header is the same
 	 * (except for the sequence number) for all generated packets.  This
 	 * makes it impossible to transmit any options which vary per generated
 	 * segment or packet.
@@ -556,9 +556,9 @@ after_sack_rexmit:
 	if ((tp->t_flags & TF_TSO) && V_tcp_do_tso && len > tp->t_maxseg &&
 	    (tp->t_port == 0) &&
 	    ((tp->t_flags & TF_SIGNATURE) == 0) &&
-	    tp->rcv_numsacks == 0 && ((sack_rxmit == 0) || V_tcp_sack_tso) &&
+	    ((sack_rxmit == 0) || V_tcp_sack_tso) &&
 	    (ipoptlen == 0 || (ipoptlen == ipsec_optlen &&
-	    (tp->t_flags2 & TF2_IPSEC_TSO) != 0)) &&
+	     (tp->t_flags2 & TF2_IPSEC_TSO) != 0)) &&
 	    !(flags & TH_SYN))
 		tso = 1;
 
diff --git a/sys/netinet/tcp_stacks/bbr.c b/sys/netinet/tcp_stacks/bbr.c
index 866ae29eef45..4ab12884b379 100644
--- a/sys/netinet/tcp_stacks/bbr.c
+++ b/sys/netinet/tcp_stacks/bbr.c
@@ -12619,7 +12619,6 @@ recheck_resend:
 	    (len > maxseg) &&
 	    (tp->t_port == 0) &&
 	    ((tp->t_flags & TF_SIGNATURE) == 0) &&
-	    tp->rcv_numsacks == 0 &&
 	    ipoptlen == 0)
 		tso = 1;
 
diff --git a/sys/netinet/tcp_stacks/rack.c b/sys/netinet/tcp_stacks/rack.c
index e77604820b63..30b0704ed7d6 100644
--- a/sys/netinet/tcp_stacks/rack.c
+++ b/sys/netinet/tcp_stacks/rack.c
@@ -20708,7 +20708,7 @@ again:
 	if ((tp->t_flags & TF_TSO) && V_tcp_do_tso && len > segsiz &&
 	    (tp->t_port == 0) &&
 	    ((tp->t_flags & TF_SIGNATURE) == 0) &&
-	    tp->rcv_numsacks == 0 && sack_rxmit == 0 &&
+	    sack_rxmit == 0 &&
 	    ipoptlen == 0)
 		tso = 1;
 	{
@@ -20910,7 +20910,6 @@ just_return_nolock:
 			    rack_use_rfo &&
 			    ((flags & (TH_SYN|TH_FIN)) == 0) &&
 			    (ipoptlen == 0) &&
-			    (tp->rcv_numsacks == 0) &&
 			    rack->r_fsb_inited &&
 			    TCPS_HAVEESTABLISHED(tp->t_state) &&
 			    ((IN_RECOVERY(tp->t_flags)) == 0) &&
@@ -22550,7 +22549,6 @@ enobufs:
 		    ((flags & (TH_SYN|TH_FIN)) == 0) &&
 		    (rsm == NULL) &&
 		    (ipoptlen == 0) &&
-		    (tp->rcv_numsacks == 0) &&
 		    rack->r_fsb_inited &&
 		    TCPS_HAVEESTABLISHED(tp->t_state) &&
 		    ((IN_RECOVERY(tp->t_flags)) == 0) &&
@@ -22578,7 +22576,6 @@ enobufs:
 		    ((flags & (TH_SYN|TH_FIN)) == 0) &&
 		    (rsm == NULL) &&
 		    (ipoptlen == 0) &&
-		    (tp->rcv_numsacks == 0) &&
 		    (rack->r_must_retran == 0) &&
 		    rack->r_fsb_inited &&
 		    TCPS_HAVEESTABLISHED(tp->t_state) &&