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// SPDX-License-Identifier: GPL-2.0-or-later
/* RxRPC Tx data buffering.
*
* Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/slab.h>
#include "ar-internal.h"
static atomic_t rxrpc_txbuf_debug_ids;
atomic_t rxrpc_nr_txbuf;
/*
* Allocate and partially initialise a data transmission buffer.
*/
struct rxrpc_txbuf *rxrpc_alloc_data_txbuf(struct rxrpc_call *call, size_t data_size,
size_t data_align, gfp_t gfp)
{
struct rxrpc_wire_header *whdr;
struct rxrpc_txbuf *txb;
size_t total, hoff = 0;
void *buf;
txb = kmalloc(sizeof(*txb), gfp);
if (!txb)
return NULL;
if (data_align)
hoff = round_up(sizeof(*whdr), data_align) - sizeof(*whdr);
total = hoff + sizeof(*whdr) + data_size;
mutex_lock(&call->conn->tx_data_alloc_lock);
buf = __page_frag_alloc_align(&call->conn->tx_data_alloc, total, gfp,
~(data_align - 1) & ~(L1_CACHE_BYTES - 1));
mutex_unlock(&call->conn->tx_data_alloc_lock);
if (!buf) {
kfree(txb);
return NULL;
}
whdr = buf + hoff;
INIT_LIST_HEAD(&txb->call_link);
INIT_LIST_HEAD(&txb->tx_link);
refcount_set(&txb->ref, 1);
txb->last_sent = KTIME_MIN;
txb->call_debug_id = call->debug_id;
txb->debug_id = atomic_inc_return(&rxrpc_txbuf_debug_ids);
txb->space = data_size;
txb->len = 0;
txb->offset = sizeof(*whdr);
txb->flags = call->conn->out_clientflag;
txb->ack_why = 0;
txb->seq = call->tx_prepared + 1;
txb->serial = 0;
txb->cksum = 0;
txb->nr_kvec = 1;
txb->kvec[0].iov_base = whdr;
txb->kvec[0].iov_len = sizeof(*whdr);
whdr->epoch = htonl(call->conn->proto.epoch);
whdr->cid = htonl(call->cid);
whdr->callNumber = htonl(call->call_id);
whdr->seq = htonl(txb->seq);
whdr->type = RXRPC_PACKET_TYPE_DATA;
whdr->flags = 0;
whdr->userStatus = 0;
whdr->securityIndex = call->security_ix;
whdr->_rsvd = 0;
whdr->serviceId = htons(call->dest_srx.srx_service);
trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, 1,
rxrpc_txbuf_alloc_data);
atomic_inc(&rxrpc_nr_txbuf);
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;
INIT_LIST_HEAD(&txb->call_link);
INIT_LIST_HEAD(&txb->tx_link);
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;
__refcount_inc(&txb->ref, &r);
trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, r + 1, what);
}
void rxrpc_see_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what)
{
int r = refcount_read(&txb->ref);
trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, r, what);
}
static void rxrpc_free_txbuf(struct rxrpc_txbuf *txb)
{
int i;
trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, 0,
rxrpc_txbuf_free);
for (i = 0; i < txb->nr_kvec; i++)
if (txb->kvec[i].iov_base)
page_frag_free(txb->kvec[i].iov_base);
kfree(txb);
atomic_dec(&rxrpc_nr_txbuf);
}
void rxrpc_put_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what)
{
unsigned int debug_id, call_debug_id;
rxrpc_seq_t seq;
bool dead;
int r;
if (txb) {
debug_id = txb->debug_id;
call_debug_id = txb->call_debug_id;
seq = txb->seq;
dead = __refcount_dec_and_test(&txb->ref, &r);
trace_rxrpc_txbuf(debug_id, call_debug_id, seq, r - 1, what);
if (dead)
rxrpc_free_txbuf(txb);
}
}
/*
* Shrink the transmit buffer.
*/
void rxrpc_shrink_call_tx_buffer(struct rxrpc_call *call)
{
struct rxrpc_txbuf *txb;
rxrpc_seq_t hard_ack = smp_load_acquire(&call->acks_hard_ack);
bool wake = false;
_enter("%x/%x/%x", call->tx_bottom, call->acks_hard_ack, call->tx_top);
while ((txb = list_first_entry_or_null(&call->tx_buffer,
struct rxrpc_txbuf, call_link))) {
hard_ack = smp_load_acquire(&call->acks_hard_ack);
if (before(hard_ack, txb->seq))
break;
if (txb->seq != call->tx_bottom + 1)
rxrpc_see_txbuf(txb, rxrpc_txbuf_see_out_of_step);
ASSERTCMP(txb->seq, ==, call->tx_bottom + 1);
smp_store_release(&call->tx_bottom, call->tx_bottom + 1);
list_del_rcu(&txb->call_link);
trace_rxrpc_txqueue(call, rxrpc_txqueue_dequeue);
rxrpc_put_txbuf(txb, rxrpc_txbuf_put_rotated);
if (after(call->acks_hard_ack, call->tx_bottom + 128))
wake = true;
}
if (wake)
wake_up(&call->waitq);
}
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