kernel/linux.git/net/rds/rds.h, branch linux-7.1.y

net/rds: Trigger rds_send_ping() more than once

2026-02-05T04:46:39+00:00

Even though a peer may have already received a non-zero value for "RDS_EXTHDR_NPATHS" from a node in the past, the current peer may not. Therefore it is important to initiate another rds_send_ping() after a re-connect to any peer: It is unknown at that time if we're still talking to the same instance of RDS kernel modules on the other side. Otherwise, the peer may just operate on a single lane ("c_npaths == 0"), not knowing that more lanes are available. However, if "c_with_sport_idx" is supported, we also need to check that the connection we accepted on lane#0 meets the proper source port modulo requirement, as we fan out: Since the exchange of "RDS_EXTHDR_NPATHS" and "RDS_EXTHDR_SPORT_IDX" is asynchronous, initially we have no choice but to accept an incoming connection (via "accept") in the first slot ("cp_index == 0") for backwards compatibility. But that very connection may have come from a different lane with "cp_index != 0", since the peer thought that we already understood and handled "c_with_sport_idx" properly, as indicated by a previous exchange before a module was reloaded. In short: If a module gets reloaded, we recover from that, but do *not* allow a downgrade to support fewer lanes. Downgrades would require us to merge messages from separate lanes, which is rather tricky with the current RDS design. Each lane has its own sequence number space and all messages would need to be re-sequenced as we merge, all while handling "RDS_FLAG_RETRANSMITTED" and "cp_retrans" properly. Signed-off-by: Gerd Rausch Signed-off-by: Allison Henderson Link: https://patch.msgid.link/20260203055723.1085751-9-achender@kernel.org Signed-off-by: Jakub Kicinski

net/rds: Use the first lane until RDS_EXTHDR_NPATHS arrives

2026-02-05T04:46:39+00:00

Instead of just blocking the sender until "c_npaths" is known (it gets updated upon the receipt of a MPRDS PONG message), simply use the first lane (cp_index#0). But just using the first lane isn't enough. As soon as we enqueue messages on a different lane, we'd run the risk of out-of-order delivery of RDS messages. Earlier messages enqueued on "cp_index == 0" could be delivered later than more recent messages enqueued on "cp_index > 0", mostly because of possible head of line blocking issues causing the first lane to be slower. To avoid that, we simply take a snapshot of "cp_next_tx_seq" at the time we're about to fan-out to more lanes. Then we delay the transmission of messages enqueued on other lanes with "cp_index > 0" until cp_index#0 caught up with the delivery of new messages (from "cp_send_queue") as well as in-flight messages (from "cp_retrans") that haven't been acknowledged yet by the receiver. We also add a new counter "mprds_catchup_tx0_retries" to keep track of how many times "rds_send_xmit" had to suspend activities, because it was waiting for the first lane to catch up. Signed-off-by: Gerd Rausch Signed-off-by: Allison Henderson Link: https://patch.msgid.link/20260203055723.1085751-8-achender@kernel.org Signed-off-by: Jakub Kicinski

net/rds: Update struct rds_statistics to use u64 instead of uint64_t

2026-02-05T04:46:38+00:00

Quick clean up to avoid checkpatch errors when adding members to this struct (Prefer kernel type 'u64' over 'uint64_t'). No functional changes added. Signed-off-by: Allison Henderson Link: https://patch.msgid.link/20260203055723.1085751-7-achender@kernel.org Signed-off-by: Jakub Kicinski

net/rds: Encode cp_index in TCP source port

2026-02-05T04:46:38+00:00

Upon "sendmsg", RDS/TCP selects a backend connection based on a hash calculated from the source-port ("RDS_MPATH_HASH"). However, "rds_tcp_accept_one" accepts connections in the order they arrive, which is non-deterministic. Therefore the mapping of the sender's "cp->cp_index" to that of the receiver changes if the backend connections are dropped and reconnected. However, connection state that's preserved across reconnects (e.g. "cp_next_rx_seq") relies on that sender<->receiver mapping to never change. So we make sure that client and server of the TCP connection have the exact same "cp->cp_index" across reconnects by encoding "cp->cp_index" in the lower three bits of the client's TCP source port. A new extension "RDS_EXTHDR_SPORT_IDX" is introduced, that allows the server to tell the difference between clients that do the "cp->cp_index" encoding, and legacy clients that pick source ports randomly. Signed-off-by: Gerd Rausch Signed-off-by: Allison Henderson Link: https://patch.msgid.link/20260203055723.1085751-3-achender@kernel.org Signed-off-by: Jakub Kicinski

net/rds: new extension header: rdma bytes

2026-02-05T04:46:38+00:00

Introduce a new extension header type RDSV3_EXTHDR_RDMA_BYTES for an RDMA initiator to exchange rdma byte counts to its target. Currently, RDMA operations cannot precisely account how many bytes a peer just transferred via RDMA, which limits per-connection statistics and future policy (e.g., monitoring or rate/cgroup accounting of RDMA traffic). In this patch we expand rds_message_add_extension to accept multiple extensions, and add new flag to RDS header: RDS_FLAG_EXTHDR_EXTENSION, along with a new extension to RDS header: rds_ext_header_rdma_bytes. Signed-off-by: Shamir Rabinovitch Signed-off-by: Guangyu Sun Signed-off-by: Allison Henderson Link: https://patch.msgid.link/20260203055723.1085751-2-achender@kernel.org Signed-off-by: Jakub Kicinski

net/rds: rds_tcp_accept_one ought to not discard messages

2026-01-23T19:51:31+00:00

RDS/TCP differs from RDS/RDMA in that message acknowledgment is done based on TCP sequence numbers: As soon as the last byte of a message has been acknowledged by the TCP stack of a peer, "rds_tcp_write_space()" goes on to discard prior messages from the send queue. Which is fine, for as long as the receiver never throws any messages away. Unfortunately, that is *not* the case since the introduction of MPRDS: commit 1a0e100fb2c96 "RDS: TCP: Enable multipath RDS for TCP" A new function "rds_tcp_accept_one_path" was introduced, which is entitled to return "NULL", if no connection path is currently available. Unfortunately, this happens after the "->accept()" call, and the new socket often already contains messages, since the peer already transitioned to "RDS_CONN_UP" on behalf of "TCP_ESTABLISHED". That's also the case after this [1]: commit 1a0e100fb2c96 "RDS: TCP: Force every connection to be initiated by numerically smaller IP address" which tried to address the situation of pending data by only transitioning connections from a smaller IP address to "RDS_CONN_UP". But even in those cases, and in particular if the "RDS_EXTHDR_NPATHS" handshake has not occurred yet, and therefore we're working with "c_npaths <= 1", "c_conn[0]" may be in a state distinct from "RDS_CONN_DOWN", and therefore all messages on the just accepted socket will be tossed away. This fix changes "rds_tcp_accept_one": * If connected from a peer with a larger IP address, the new socket will continue to get closed right away. With commit [1] above, there should not be any messages in the socket receive buffer, since the peer never transitioned to "RDS_CONN_UP". Therefore it should be okay to not make any efforts to dispatch the socket receive buffer. * If connected from a peer with a smaller IP address, we call "rds_tcp_accept_one_path" to find a free slot/"path". If found, business goes on as usual. If none was found, we save/stash the newly accepted socket into "rds_tcp_accepted_sock", in order to not lose any messages that may have arrived already. We then return from "rds_tcp_accept_one" with "-ENOBUFS". Later on, when a slot/"path" does become available again (e.g. state transitioned to "RDS_CONN_DOWN", or HS extension header was received with "c_npaths > 1") we call "rds_tcp_conn_slots_available" that simply re-issues a "rds_tcp_accept_one_path" worker-callback and picks up the new socket from "rds_tcp_accepted_sock", and thereby continuing where it left with "-ENOBUFS" last time. Since a new slot has become available, those messages won't be lost, since processing proceeds as if that slot had been available the first time around. Signed-off-by: Gerd Rausch Signed-off-by: Jack Vogel Signed-off-by: Allison Henderson Link: https://patch.msgid.link/20260122055213.83608-3-achender@kernel.org Signed-off-by: Jakub Kicinski

net/rds: Add per cp work queue

2026-01-13T11:27:03+00:00

This patch adds a per connection workqueue which can be initialized and used independently of the globally shared rds_wq. This patch is the first in a series that aims to address tcp ack timeouts during the tcp socket shutdown sequence. This initial refactoring lays the ground work needed to alleviate queue congestion during heavy reads and writes. The independently managed queues will allow shutdowns and reconnects respond more quickly before the peer(s) timeout waiting for the proper acks. Signed-off-by: Allison Henderson Link: https://patch.msgid.link/20260109224843.128076-2-achender@kernel.org Signed-off-by: Paolo Abeni

net: Convert proto_ops bind() callbacks to use sockaddr_unsized

2025-11-05T03:10:32+00:00

Update all struct proto_ops bind() callback function prototypes from "struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the compiler about object sizes. Calls into struct proto handlers gain casts that will be removed in the struct proto conversion patch. No binary changes expected. Signed-off-by: Kees Cook Link: https://patch.msgid.link/20251104002617.2752303-2-kees@kernel.org Signed-off-by: Jakub Kicinski

rds: Fix endianness annotation for RDS_MPATH_HASH

2025-08-22T23:44:39+00:00

jhash_1word accepts host endian inputs while rs_bound_port is a be16 value (sockaddr_in6.sin6_port). Use ntohs() for consistency. Flagged by Sparse. Signed-off-by: Ujwal Kundur Reviewed-by: Allison Henderson Link: https://patch.msgid.link/20250820175550.498-4-ujwal.kundur@gmail.com Signed-off-by: Jakub Kicinski

net/rds: Remove unused function declarations

2023-08-13T11:25:42+00:00

Commit 39de8281791c ("RDS: Main header file") declared but never implemented rds_trans_init() and rds_trans_exit(), remove it. Commit d37c9359056f ("RDS: Move loop-only function to loop.c") removed the implementation rds_message_inc_free() but not the declaration. Since commit 55b7ed0b582f ("RDS: Common RDMA transport code") rds_rdma_conn_connect() is never implemented and used. rds_tcp_map_seq() is never implemented and used since commit 70041088e3b9 ("RDS: Add TCP transport to RDS"). Signed-off-by: Yue Haibing Reviewed-by: Simon Horman Signed-off-by: David S. Miller