Linux kernel mirror (for testing)
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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* RxRPC Tx data buffering.
3 *
4 * Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/slab.h>
11#include "ar-internal.h"
12
13static atomic_t rxrpc_txbuf_debug_ids;
14atomic_t rxrpc_nr_txbuf;
15
16/*
17 * Allocate and partially initialise an I/O request structure.
18 */
19struct rxrpc_txbuf *rxrpc_alloc_txbuf(struct rxrpc_call *call, u8 packet_type,
20 gfp_t gfp)
21{
22 struct rxrpc_txbuf *txb;
23
24 txb = kmalloc(sizeof(*txb), gfp);
25 if (txb) {
26 INIT_LIST_HEAD(&txb->call_link);
27 INIT_LIST_HEAD(&txb->tx_link);
28 refcount_set(&txb->ref, 1);
29 txb->call_debug_id = call->debug_id;
30 txb->debug_id = atomic_inc_return(&rxrpc_txbuf_debug_ids);
31 txb->space = sizeof(txb->data);
32 txb->len = 0;
33 txb->offset = 0;
34 txb->flags = 0;
35 txb->ack_why = 0;
36 txb->seq = call->tx_prepared + 1;
37 txb->wire.epoch = htonl(call->conn->proto.epoch);
38 txb->wire.cid = htonl(call->cid);
39 txb->wire.callNumber = htonl(call->call_id);
40 txb->wire.seq = htonl(txb->seq);
41 txb->wire.type = packet_type;
42 txb->wire.flags = call->conn->out_clientflag;
43 txb->wire.userStatus = 0;
44 txb->wire.securityIndex = call->security_ix;
45 txb->wire._rsvd = 0;
46 txb->wire.serviceId = htons(call->dest_srx.srx_service);
47
48 trace_rxrpc_txbuf(txb->debug_id,
49 txb->call_debug_id, txb->seq, 1,
50 packet_type == RXRPC_PACKET_TYPE_DATA ?
51 rxrpc_txbuf_alloc_data :
52 rxrpc_txbuf_alloc_ack);
53 atomic_inc(&rxrpc_nr_txbuf);
54 }
55
56 return txb;
57}
58
59void rxrpc_get_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what)
60{
61 int r;
62
63 __refcount_inc(&txb->ref, &r);
64 trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, r + 1, what);
65}
66
67void rxrpc_see_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what)
68{
69 int r = refcount_read(&txb->ref);
70
71 trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, r, what);
72}
73
74static void rxrpc_free_txbuf(struct rcu_head *rcu)
75{
76 struct rxrpc_txbuf *txb = container_of(rcu, struct rxrpc_txbuf, rcu);
77
78 trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, 0,
79 rxrpc_txbuf_free);
80 kfree(txb);
81 atomic_dec(&rxrpc_nr_txbuf);
82}
83
84void rxrpc_put_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what)
85{
86 unsigned int debug_id, call_debug_id;
87 rxrpc_seq_t seq;
88 bool dead;
89 int r;
90
91 if (txb) {
92 debug_id = txb->debug_id;
93 call_debug_id = txb->call_debug_id;
94 seq = txb->seq;
95 dead = __refcount_dec_and_test(&txb->ref, &r);
96 trace_rxrpc_txbuf(debug_id, call_debug_id, seq, r - 1, what);
97 if (dead)
98 call_rcu(&txb->rcu, rxrpc_free_txbuf);
99 }
100}
101
102/*
103 * Shrink the transmit buffer.
104 */
105void rxrpc_shrink_call_tx_buffer(struct rxrpc_call *call)
106{
107 struct rxrpc_txbuf *txb;
108 rxrpc_seq_t hard_ack = smp_load_acquire(&call->acks_hard_ack);
109 bool wake = false;
110
111 _enter("%x/%x/%x", call->tx_bottom, call->acks_hard_ack, call->tx_top);
112
113 for (;;) {
114 spin_lock(&call->tx_lock);
115 txb = list_first_entry_or_null(&call->tx_buffer,
116 struct rxrpc_txbuf, call_link);
117 if (!txb)
118 break;
119 hard_ack = smp_load_acquire(&call->acks_hard_ack);
120 if (before(hard_ack, txb->seq))
121 break;
122
123 if (txb->seq != call->tx_bottom + 1)
124 rxrpc_see_txbuf(txb, rxrpc_txbuf_see_out_of_step);
125 ASSERTCMP(txb->seq, ==, call->tx_bottom + 1);
126 smp_store_release(&call->tx_bottom, call->tx_bottom + 1);
127 list_del_rcu(&txb->call_link);
128
129 trace_rxrpc_txqueue(call, rxrpc_txqueue_dequeue);
130
131 spin_unlock(&call->tx_lock);
132
133 rxrpc_put_txbuf(txb, rxrpc_txbuf_put_rotated);
134 if (after(call->acks_hard_ack, call->tx_bottom + 128))
135 wake = true;
136 }
137
138 spin_unlock(&call->tx_lock);
139
140 if (wake)
141 wake_up(&call->waitq);
142}