[net-next,30/37] rxrpc: Don't allocate a txbuf for an ACK transmission

Message ID	20241202143057.378147-31-dhowells@redhat.com (mailing list archive)
State	New
Delegated to:	Netdev Maintainers
Headers	show Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 91A2A217F2C for <netdev@vger.kernel.org>; Mon, 2 Dec 2024 14:33:13 +0000 (UTC) From: David Howells <dhowells@redhat.com> To: netdev@vger.kernel.org Cc: David Howells <dhowells@redhat.com>, Marc Dionne <marc.dionne@auristor.com>, Yunsheng Lin <linyunsheng@huawei.com>, "David S. Miller" <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>, linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next 30/37] rxrpc: Don't allocate a txbuf for an ACK transmission Date: Mon, 2 Dec 2024 14:30:48 +0000 Message-ID: <20241202143057.378147-31-dhowells@redhat.com> In-Reply-To: <20241202143057.378147-1-dhowells@redhat.com> References: <20241202143057.378147-1-dhowells@redhat.com> Precedence: bulk MIME-Version: 1.0 Content-Transfer-Encoding: 8bit
Series	rxrpc: Implement jumbo DATA transmission and RACK-TLP \| expand [net-next,00/37] rxrpc: Implement jumbo DATA transmission and RACK-TLP [net-next,01/37] rxrpc: Fix handling of received connection abort [net-next,02/37] rxrpc: Use umin() and umax() rather than min_t()/max_t() where possible [net-next,03/37] rxrpc: Clean up Tx header flags generation handling [net-next,04/37] rxrpc: Don't set the MORE-PACKETS rxrpc wire header flag [net-next,05/37] rxrpc: Show stats counter for received reason-0 ACKs [net-next,06/37] rxrpc: Request an ACK on impending Tx stall [net-next,07/37] rxrpc: Use a large kvec[] in rxrpc_local rather than every rxrpc_txbuf [net-next,08/37] rxrpc: Implement path-MTU probing using padded PING ACKs (RFC8899) [net-next,09/37] rxrpc: Separate the packet length from the data length in rxrpc_txbuf [net-next,10/37] rxrpc: Prepare to be able to send jumbo DATA packets [net-next,11/37] rxrpc: Add a tracepoint to show variables pertinent to jumbo packet size [net-next,12/37] rxrpc: Fix CPU time starvation in I/O thread [net-next,13/37] rxrpc: Fix injection of packet loss [net-next,14/37] rxrpc: Only set DF=1 on initial DATA transmission [net-next,15/37] rxrpc: Timestamp DATA packets before transmitting them [net-next,16/37] rxrpc: Implement progressive transmission queue struct [net-next,17/37] rxrpc: call->acks_hard_ack is now the same call->tx_bottom, so remove it [net-next,18/37] rxrpc: Replace call->acks_first_seq with tracking of the hard ACK point [net-next,19/37] rxrpc: Display stats about jumbo packets transmitted and received [net-next,20/37] rxrpc: Adjust names and types of congestion-related fields [net-next,21/37] rxrpc: Use the new rxrpc_tx_queue struct to more efficiently process ACKs [net-next,22/37] rxrpc: Store the DATA serial in the txqueue and use this in RTT calc [net-next,23/37] rxrpc: Don't use received skbuff timestamps [net-next,24/37] rxrpc: Generate rtt_min [net-next,25/37] rxrpc: Adjust the rxrpc_rtt_rx tracepoint [net-next,26/37] rxrpc: Display userStatus in rxrpc_rx_ack trace [net-next,27/37] rxrpc: Fix the calculation and use of RTO [net-next,28/37] rxrpc: Fix initial resend timeout [net-next,29/37] rxrpc: Send jumbo DATA packets [net-next,30/37] rxrpc: Don't allocate a txbuf for an ACK transmission [net-next,31/37] rxrpc: Use irq-disabling spinlocks between app and I/O thread [net-next,32/37] rxrpc: Tidy up the ACK parsing a bit [net-next,33/37] rxrpc: Add a reason indicator to the tx_data tracepoint [net-next,34/37] rxrpc: Add a reason indicator to the tx_ack tracepoint [net-next,35/37] rxrpc: Manage RTT per-call rather than per-peer [net-next,36/37] rxrpc: Fix request for an ACK when cwnd is minimum [net-next,37/37] rxrpc: Implement RACK/TLP to deal with transmission stalls [RFC8985]

diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h index 7681c67f7d65..326a4c257aea 100644 --- a/include/trace/events/rxrpc.h +++ b/include/trace/events/rxrpc.h @@ -462,13 +462,11 @@ /* ---- Must update size of stat_why_req_ack[] if more are added! */ #define rxrpc_txbuf_traces \ - EM(rxrpc_txbuf_alloc_ack, "ALLOC ACK ") \ EM(rxrpc_txbuf_alloc_data, "ALLOC DATA ") \ EM(rxrpc_txbuf_free, "FREE ") \ EM(rxrpc_txbuf_get_buffer, "GET BUFFER ") \ EM(rxrpc_txbuf_get_trans, "GET TRANS ") \ EM(rxrpc_txbuf_get_retrans, "GET RETRANS") \ - EM(rxrpc_txbuf_put_ack_tx, "PUT ACK TX ") \ EM(rxrpc_txbuf_put_cleaned, "PUT CLEANED") \ EM(rxrpc_txbuf_put_nomem, "PUT NOMEM ") \ EM(rxrpc_txbuf_put_rotated, "PUT ROTATED") \ diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h index 361d4f1bfb4f..0a9fad23c9ac 100644 --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -835,11 +835,9 @@ struct rxrpc_txbuf { #define RXRPC_TXBUF_WIRE_FLAGS 0xff /* The wire protocol flags */ #define RXRPC_TXBUF_RESENT 0x100 /* Set if has been resent */ __be16 cksum; /* Checksum to go in header */ - unsigned short ack_rwind; /* ACK receive window */ - u8 /*enum rxrpc_propose_ack_trace*/ ack_why; /* If ack, why */ bool jumboable; /* Can be non-terminal jumbo subpacket */ u8 nr_kvec; /* Amount of kvec[] used */ - struct kvec kvec[3]; + struct kvec kvec[1]; }; static inline bool rxrpc_sending_to_server(const struct rxrpc_txbuf *txb) @@ -1365,7 +1363,6 @@ static inline void rxrpc_sysctl_exit(void) {} extern atomic_t rxrpc_nr_txbuf; struct rxrpc_txbuf *rxrpc_alloc_data_txbuf(struct rxrpc_call *call, size_t data_size, size_t data_align, gfp_t gfp); -struct rxrpc_txbuf *rxrpc_alloc_ack_txbuf(struct rxrpc_call *call, size_t sack_size); void rxrpc_get_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what); void rxrpc_see_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what); void rxrpc_put_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what); diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c index 50798a641e37..73c37689c54f 100644 --- a/net/rxrpc/output.c +++ b/net/rxrpc/output.c @@ -71,22 +71,97 @@ static void rxrpc_set_keepalive(struct rxrpc_call *call, ktime_t now) trace_rxrpc_timer_set(call, delay, rxrpc_timer_trace_keepalive); } +/* + * Allocate transmission buffers for an ACK and attach them to local->kv[]. + */ +static int rxrpc_alloc_ack(struct rxrpc_call *call, size_t sack_size) +{ + struct rxrpc_wire_header *whdr; + struct rxrpc_acktrailer *trailer; + struct rxrpc_ackpacket *ack; + struct kvec *kv = call->local->kvec; + gfp_t gfp = rcu_read_lock_held() ? GFP_ATOMIC | __GFP_NOWARN : GFP_NOFS; + void *buf, *buf2 = NULL; + u8 *filler; + + buf = page_frag_alloc(&call->local->tx_alloc, + sizeof(*whdr) + sizeof(*ack) + 1 + 3 + sizeof(*trailer), gfp); + if (!buf) + return -ENOMEM; + + if (sack_size) { + buf2 = page_frag_alloc(&call->local->tx_alloc, sack_size, gfp); + if (!buf2) { + page_frag_free(buf); + return -ENOMEM; + } + } + + whdr = buf; + ack = buf + sizeof(*whdr); + filler = buf + sizeof(*whdr) + sizeof(*ack) + 1; + trailer = buf + sizeof(*whdr) + sizeof(*ack) + 1 + 3; + + kv[0].iov_base = whdr; + kv[0].iov_len = sizeof(*whdr) + sizeof(*ack); + kv[1].iov_base = buf2; + kv[1].iov_len = sack_size; + kv[2].iov_base = filler; + kv[2].iov_len = 3 + sizeof(*trailer); + return 3; /* Number of kvec[] used. */ +} + +static void rxrpc_free_ack(struct rxrpc_call *call) +{ + page_frag_free(call->local->kvec[0].iov_base); + if (call->local->kvec[1].iov_base) + page_frag_free(call->local->kvec[1].iov_base); +} + +/* + * Record the beginning of an RTT probe. + */ +static void rxrpc_begin_rtt_probe(struct rxrpc_call *call, rxrpc_serial_t serial, + ktime_t now, enum rxrpc_rtt_tx_trace why) +{ + unsigned long avail = call->rtt_avail; + int rtt_slot = 9; + + if (!(avail & RXRPC_CALL_RTT_AVAIL_MASK)) + goto no_slot; + + rtt_slot = __ffs(avail & RXRPC_CALL_RTT_AVAIL_MASK); + if (!test_and_clear_bit(rtt_slot, &call->rtt_avail)) + goto no_slot; + + call->rtt_serial[rtt_slot] = serial; + call->rtt_sent_at[rtt_slot] = now; + smp_wmb(); /* Write data before avail bit */ + set_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail); + + trace_rxrpc_rtt_tx(call, why, rtt_slot, serial); + return; + +no_slot: + trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_no_slot, rtt_slot, serial); +} + /* * Fill out an ACK packet. */ -static void rxrpc_fill_out_ack(struct rxrpc_call *call, - struct rxrpc_txbuf *txb, - u8 ack_reason, - rxrpc_serial_t serial) +static int rxrpc_fill_out_ack(struct rxrpc_call *call, int nr_kv, u8 ack_reason, + rxrpc_serial_t serial_to_ack, rxrpc_serial_t *_ack_serial) { - struct rxrpc_wire_header *whdr = txb->kvec[0].iov_base; - struct rxrpc_acktrailer *trailer = txb->kvec[2].iov_base + 3; + struct kvec *kv = call->local->kvec; + struct rxrpc_wire_header *whdr = kv[0].iov_base; + struct rxrpc_acktrailer *trailer = kv[2].iov_base + 3; struct rxrpc_ackpacket *ack = (struct rxrpc_ackpacket *)(whdr + 1); unsigned int qsize, sack, wrap, to, max_mtu, if_mtu; rxrpc_seq_t window, wtop; + ktime_t now = ktime_get_real(); int rsize; - u8 *filler = txb->kvec[2].iov_base; - u8 *sackp = txb->kvec[1].iov_base; + u8 *filler = kv[2].iov_base; + u8 *sackp = kv[1].iov_base; rxrpc_inc_stat(call->rxnet, stat_tx_ack_fill); @@ -94,14 +169,25 @@ static void rxrpc_fill_out_ack(struct rxrpc_call *call, wtop = call->ackr_wtop; sack = call->ackr_sack_base % RXRPC_SACK_SIZE; + *_ack_serial = rxrpc_get_next_serial(call->conn); + + whdr->epoch = htonl(call->conn->proto.epoch); + whdr->cid = htonl(call->cid); + whdr->callNumber = htonl(call->call_id); + whdr->serial = htonl(*_ack_serial); whdr->seq = 0; whdr->type = RXRPC_PACKET_TYPE_ACK; - txb->flags |= RXRPC_SLOW_START_OK; + whdr->flags = call->conn->out_clientflag | RXRPC_SLOW_START_OK; + whdr->userStatus = 0; + whdr->securityIndex = call->security_ix; + whdr->_rsvd = 0; + whdr->serviceId = htons(call->dest_srx.srx_service); + ack->bufferSpace = 0; ack->maxSkew = 0; ack->firstPacket = htonl(window); ack->previousPacket = htonl(call->rx_highest_seq); - ack->serial = htonl(serial); + ack->serial = htonl(serial_to_ack); ack->reason = ack_reason; ack->nAcks = wtop - window; filler[0] = 0; @@ -109,12 +195,10 @@ static void rxrpc_fill_out_ack(struct rxrpc_call *call, filler[2] = 0; if (ack_reason == RXRPC_ACK_PING) - txb->flags |= RXRPC_REQUEST_ACK; + whdr->flags |= RXRPC_REQUEST_ACK; if (after(wtop, window)) { - txb->len += ack->nAcks; - txb->kvec[1].iov_base = sackp; - txb->kvec[1].iov_len = ack->nAcks; + kv[1].iov_len = ack->nAcks; wrap = RXRPC_SACK_SIZE - sack; to = umin(ack->nAcks, RXRPC_SACK_SIZE); @@ -133,7 +217,6 @@ static void rxrpc_fill_out_ack(struct rxrpc_call *call, qsize = (window - 1) - call->rx_consumed; rsize = max_t(int, call->rx_winsize - qsize, 0); - txb->ack_rwind = rsize; if_mtu = call->peer->if_mtu - call->peer->hdrsize; if (call->peer->ackr_adv_pmtud) { @@ -146,48 +229,27 @@ static void rxrpc_fill_out_ack(struct rxrpc_call *call, trailer->ifMTU = htonl(if_mtu); trailer->rwind = htonl(rsize); trailer->jumbo_max = 0; /* Advertise pmtu discovery */ -} - -/* - * Record the beginning of an RTT probe. - */ -static void rxrpc_begin_rtt_probe(struct rxrpc_call *call, rxrpc_serial_t serial, - ktime_t now, enum rxrpc_rtt_tx_trace why) -{ - unsigned long avail = call->rtt_avail; - int rtt_slot = 9; - if (!(avail & RXRPC_CALL_RTT_AVAIL_MASK)) - goto no_slot; - - rtt_slot = __ffs(avail & RXRPC_CALL_RTT_AVAIL_MASK); - if (!test_and_clear_bit(rtt_slot, &call->rtt_avail)) - goto no_slot; - - call->rtt_serial[rtt_slot] = serial; - call->rtt_sent_at[rtt_slot] = now; - smp_wmb(); /* Write data before avail bit */ - set_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail); - - trace_rxrpc_rtt_tx(call, why, rtt_slot, serial); - return; - -no_slot: - trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_no_slot, rtt_slot, serial); + if (ack_reason == RXRPC_ACK_PING) + rxrpc_begin_rtt_probe(call, *_ack_serial, now, rxrpc_rtt_tx_ping); + if (whdr->flags & RXRPC_REQUEST_ACK) + call->peer->rtt_last_req = now; + rxrpc_set_keepalive(call, now); + return nr_kv; } /* * Transmit an ACK packet. */ -static void rxrpc_send_ack_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb, - int nr_kv, enum rxrpc_propose_ack_trace why) +static void rxrpc_send_ack_packet(struct rxrpc_call *call, int nr_kv, size_t len, + rxrpc_serial_t serial, enum rxrpc_propose_ack_trace why) { struct kvec *kv = call->local->kvec; struct rxrpc_wire_header *whdr = kv[0].iov_base; + struct rxrpc_acktrailer *trailer = kv[2].iov_base + 3; struct rxrpc_connection *conn; struct rxrpc_ackpacket *ack = (struct rxrpc_ackpacket *)(whdr + 1); struct msghdr msg; - ktime_t now; int ret; if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags)) @@ -201,41 +263,31 @@ static void rxrpc_send_ack_packet(struct rxrpc_call *call, struct rxrpc_txbuf *t msg.msg_controllen = 0; msg.msg_flags = MSG_SPLICE_PAGES; - whdr->flags = txb->flags & RXRPC_TXBUF_WIRE_FLAGS; - - txb->serial = rxrpc_get_next_serial(conn); - whdr->serial = htonl(txb->serial); - trace_rxrpc_tx_ack(call->debug_id, txb->serial, + trace_rxrpc_tx_ack(call->debug_id, serial, ntohl(ack->firstPacket), ntohl(ack->serial), ack->reason, ack->nAcks, - txb->ack_rwind); + ntohl(trailer->rwind)); rxrpc_inc_stat(call->rxnet, stat_tx_ack_send); - iov_iter_kvec(&msg.msg_iter, WRITE, kv, nr_kv, txb->len); + iov_iter_kvec(&msg.msg_iter, WRITE, kv, nr_kv, len); rxrpc_local_dont_fragment(conn->local, why == rxrpc_propose_ack_ping_for_mtu_probe); - ret = do_udp_sendmsg(conn->local->socket, &msg, txb->len); + ret = do_udp_sendmsg(conn->local->socket, &msg, len); call->peer->last_tx_at = ktime_get_seconds(); if (ret < 0) { - trace_rxrpc_tx_fail(call->debug_id, txb->serial, ret, + trace_rxrpc_tx_fail(call->debug_id, serial, ret, rxrpc_tx_point_call_ack); if (why == rxrpc_propose_ack_ping_for_mtu_probe && ret == -EMSGSIZE) - rxrpc_input_probe_for_pmtud(conn, txb->serial, true); + rxrpc_input_probe_for_pmtud(conn, serial, true); } else { trace_rxrpc_tx_packet(call->debug_id, whdr, rxrpc_tx_point_call_ack); - now = ktime_get_real(); - if (ack->reason == RXRPC_ACK_PING) - rxrpc_begin_rtt_probe(call, txb->serial, now, rxrpc_rtt_tx_ping); - if (txb->flags & RXRPC_REQUEST_ACK) - call->peer->rtt_last_req = now; - rxrpc_set_keepalive(call, now); if (why == rxrpc_propose_ack_ping_for_mtu_probe) { call->peer->pmtud_pending = false; call->peer->pmtud_probing = true; - call->conn->pmtud_probe = txb->serial; + call->conn->pmtud_probe = serial; call->conn->pmtud_call = call->debug_id; trace_rxrpc_pmtud_tx(call); } @@ -247,10 +299,11 @@ static void rxrpc_send_ack_packet(struct rxrpc_call *call, struct rxrpc_txbuf *t * Queue an ACK for immediate transmission. */ void rxrpc_send_ACK(struct rxrpc_call *call, u8 ack_reason, - rxrpc_serial_t serial, enum rxrpc_propose_ack_trace why) + rxrpc_serial_t serial_to_ack, enum rxrpc_propose_ack_trace why) { - struct rxrpc_txbuf *txb; struct kvec *kv = call->local->kvec; + rxrpc_serial_t ack_serial; + size_t len; int nr_kv; if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags)) @@ -258,32 +311,29 @@ void rxrpc_send_ACK(struct rxrpc_call *call, u8 ack_reason, rxrpc_inc_stat(call->rxnet, stat_tx_acks[ack_reason]); - txb = rxrpc_alloc_ack_txbuf(call, call->ackr_wtop - call->ackr_window); - if (!txb) { + nr_kv = rxrpc_alloc_ack(call, call->ackr_wtop - call->ackr_window); + if (nr_kv < 0) { kleave(" = -ENOMEM"); return; } - txb->ack_why = why; - - rxrpc_fill_out_ack(call, txb, ack_reason, serial); + nr_kv = rxrpc_fill_out_ack(call, nr_kv, ack_reason, serial_to_ack, &ack_serial); + len = kv[0].iov_len; + len += kv[1].iov_len; + len += kv[2].iov_len; /* Extend a path MTU probe ACK. */ - nr_kv = txb->nr_kvec; - kv[0] = txb->kvec[0]; - kv[1] = txb->kvec[1]; - kv[2] = txb->kvec[2]; if (why == rxrpc_propose_ack_ping_for_mtu_probe) { size_t probe_mtu = call->peer->pmtud_trial + sizeof(struct rxrpc_wire_header); - if (txb->len > probe_mtu) + if (len > probe_mtu) goto skip; - while (txb->len < probe_mtu) { - size_t part = umin(probe_mtu - txb->len, PAGE_SIZE); + while (len < probe_mtu) { + size_t part = umin(probe_mtu - len, PAGE_SIZE); kv[nr_kv].iov_base = page_address(ZERO_PAGE(0)); kv[nr_kv].iov_len = part; - txb->len += part; + len += part; nr_kv++; } } @@ -292,10 +342,10 @@ void rxrpc_send_ACK(struct rxrpc_call *call, u8 ack_reason, atomic_set(&call->ackr_nr_consumed, 0); clear_bit(RXRPC_CALL_RX_IS_IDLE, &call->flags); - trace_rxrpc_send_ack(call, why, ack_reason, serial); - rxrpc_send_ack_packet(call, txb, nr_kv, why); + trace_rxrpc_send_ack(call, why, ack_reason, ack_serial); + rxrpc_send_ack_packet(call, nr_kv, len, ack_serial, why); skip: - rxrpc_put_txbuf(txb, rxrpc_txbuf_put_ack_tx); + rxrpc_free_ack(call); } /* diff --git a/net/rxrpc/txbuf.c b/net/rxrpc/txbuf.c index 067223c8c35f..131d9e55c8e9 100644 --- a/net/rxrpc/txbuf.c +++ b/net/rxrpc/txbuf.c @@ -73,82 +73,6 @@ struct rxrpc_txbuf *rxrpc_alloc_data_txbuf(struct rxrpc_call *call, size_t data_ return txb; } -/* - * Allocate and partially initialise an ACK packet. - */ -struct rxrpc_txbuf *rxrpc_alloc_ack_txbuf(struct rxrpc_call *call, size_t sack_size) -{ - struct rxrpc_wire_header *whdr; - struct rxrpc_acktrailer *trailer; - struct rxrpc_ackpacket *ack; - struct rxrpc_txbuf *txb; - gfp_t gfp = rcu_read_lock_held() ? GFP_ATOMIC | __GFP_NOWARN : GFP_NOFS; - void *buf, *buf2 = NULL; - u8 *filler; - - txb = kmalloc(sizeof(*txb), gfp); - if (!txb) - return NULL; - - buf = page_frag_alloc(&call->local->tx_alloc, - sizeof(*whdr) + sizeof(*ack) + 1 + 3 + sizeof(*trailer), gfp); - if (!buf) { - kfree(txb); - return NULL; - } - - if (sack_size) { - buf2 = page_frag_alloc(&call->local->tx_alloc, sack_size, gfp); - if (!buf2) { - page_frag_free(buf); - kfree(txb); - return NULL; - } - } - - whdr = buf; - ack = buf + sizeof(*whdr); - filler = buf + sizeof(*whdr) + sizeof(*ack) + 1; - trailer = buf + sizeof(*whdr) + sizeof(*ack) + 1 + 3; - - refcount_set(&txb->ref, 1); - txb->call_debug_id = call->debug_id; - txb->debug_id = atomic_inc_return(&rxrpc_txbuf_debug_ids); - txb->space = 0; - txb->len = sizeof(*whdr) + sizeof(*ack) + 3 + sizeof(*trailer); - txb->offset = 0; - txb->flags = call->conn->out_clientflag; - txb->ack_rwind = 0; - txb->seq = 0; - txb->serial = 0; - txb->cksum = 0; - txb->nr_kvec = 3; - txb->kvec[0].iov_base = whdr; - txb->kvec[0].iov_len = sizeof(*whdr) + sizeof(*ack); - txb->kvec[1].iov_base = buf2; - txb->kvec[1].iov_len = sack_size; - txb->kvec[2].iov_base = filler; - txb->kvec[2].iov_len = 3 + sizeof(*trailer); - - whdr->epoch = htonl(call->conn->proto.epoch); - whdr->cid = htonl(call->cid); - whdr->callNumber = htonl(call->call_id); - whdr->seq = 0; - whdr->type = RXRPC_PACKET_TYPE_ACK; - whdr->flags = 0; - whdr->userStatus = 0; - whdr->securityIndex = call->security_ix; - whdr->_rsvd = 0; - whdr->serviceId = htons(call->dest_srx.srx_service); - - get_page(virt_to_head_page(trailer)); - - trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, 1, - rxrpc_txbuf_alloc_ack); - atomic_inc(&rxrpc_nr_txbuf); - return txb; -} - void rxrpc_get_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what) { int r;

[net-next,30/37] rxrpc: Don't allocate a txbuf for an ACK transmission

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