Merge branch 'net-rds-rds-tcp-protocol-and-extension-improvements'

Allison Henderson says:

====================
net/rds: RDS-TCP protocol and extension improvements

This is subset 3 of the larger RDS-TCP patch series I posted last
Oct.  The greater series aims to correct multiple rds-tcp issues that
can cause dropped or out of sequence messages.  I've broken it down into
smaller sets to make reviews more manageable.

In this set, we introduce extension headers for byte accounting
and fix several RDS/TCP protocol issues including message preservation
during connection transitions and multipath lane handling.

The entire set can be viewed in the rfc here:
https://lore.kernel.org/netdev/20251022191715.157755-1-achender@kernel.org/
====================

Link: https://patch.msgid.link/20260203055723.1085751-1-achender@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 33 insertions, 7 deletions

diff --git a/net/rds/ib_send.c b/net/rds/ib_send.c
index f9d28ddd168d..fcd04c29f543 100644
--- a/net/rds/ib_send.c
+++ b/net/rds/ib_send.c
@@ -577,16 +577,42 @@ int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm,
 		/* If it has a RDMA op, tell the peer we did it. This is
 		 * used by the peer to release use-once RDMA MRs. */
 		if (rm->rdma.op_active) {
-			struct rds_ext_header_rdma ext_hdr;
+			struct rds_ext_header_rdma ext_hdr = {};
+			struct rds_ext_header_rdma_bytes
+				rdma_bytes_ext_hdr = {};
 
 			ext_hdr.h_rdma_rkey = cpu_to_be32(rm->rdma.op_rkey);
-			rds_message_add_extension(&rm->m_inc.i_hdr,
-					RDS_EXTHDR_RDMA, &ext_hdr, sizeof(ext_hdr));
+			if (rds_message_add_extension(&rm->m_inc.i_hdr,
+						      RDS_EXTHDR_RDMA,
+						      &ext_hdr)) {
+				/* prepare the rdma bytes ext header */
+				rdma_bytes_ext_hdr.h_rflags =
+					rm->rdma.op_write ?
+					RDS_FLAG_RDMA_WR_BYTES :
+					RDS_FLAG_RDMA_RD_BYTES;
+				rdma_bytes_ext_hdr.h_rdma_bytes =
+					cpu_to_be32(rm->rdma.op_bytes);
+			} else {
+				rdsdebug("RDS_EXTHDR_RDMA dropped");
+			}
+
+			if (rds_message_add_extension(&rm->m_inc.i_hdr,
+						      RDS_EXTHDR_RDMA_BYTES,
+						      &rdma_bytes_ext_hdr)) {
+				/* rdma bytes ext header was added successfully,
+				 * notify the remote side via flag in header
+				 */
+				rm->m_inc.i_hdr.h_flags |=
+					RDS_FLAG_EXTHDR_EXTENSION;
+			} else {
+				rdsdebug("RDS_EXTHDR_RDMA_BYTES dropped");
+			}
 		}
-		if (rm->m_rdma_cookie) {
-			rds_message_add_rdma_dest_extension(&rm->m_inc.i_hdr,
-					rds_rdma_cookie_key(rm->m_rdma_cookie),
-					rds_rdma_cookie_offset(rm->m_rdma_cookie));
+		if (rm->m_rdma_cookie &&
+		    !rds_message_add_rdma_dest_extension(&rm->m_inc.i_hdr,
+				rds_rdma_cookie_key(rm->m_rdma_cookie),
+				rds_rdma_cookie_offset(rm->m_rdma_cookie))) {
+			rdsdebug("RDS_EXTHDR_RDMA_DEST dropped\n");
 		}
 
 		/* Note - rds_ib_piggyb_ack clears the ACK_REQUIRED bit, so