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	call->tx_buffer is now only accessed within the I/O thread (->tx_sendmsg is the way sendmsg passes packets to the I/O thread) so there's no need to lock around it. Signed-off-by: David Howells <dhowells@redhat.com> cc: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org
		
			
				
	
	
		
			135 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			135 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: GPL-2.0-or-later
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/* RxRPC Tx data buffering.
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 *
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 * Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
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 * Written by David Howells (dhowells@redhat.com)
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 */
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/slab.h>
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#include "ar-internal.h"
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static atomic_t rxrpc_txbuf_debug_ids;
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atomic_t rxrpc_nr_txbuf;
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/*
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 * Allocate and partially initialise an I/O request structure.
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 */
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struct rxrpc_txbuf *rxrpc_alloc_txbuf(struct rxrpc_call *call, u8 packet_type,
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				      gfp_t gfp)
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{
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	struct rxrpc_txbuf *txb;
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	txb = kmalloc(sizeof(*txb), gfp);
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	if (txb) {
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		INIT_LIST_HEAD(&txb->call_link);
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		INIT_LIST_HEAD(&txb->tx_link);
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		refcount_set(&txb->ref, 1);
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		txb->call_debug_id	= call->debug_id;
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		txb->debug_id		= atomic_inc_return(&rxrpc_txbuf_debug_ids);
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		txb->space		= sizeof(txb->data);
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		txb->len		= 0;
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		txb->offset		= 0;
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		txb->flags		= 0;
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		txb->ack_why		= 0;
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		txb->seq		= call->tx_prepared + 1;
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		txb->wire.epoch		= htonl(call->conn->proto.epoch);
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		txb->wire.cid		= htonl(call->cid);
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		txb->wire.callNumber	= htonl(call->call_id);
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		txb->wire.seq		= htonl(txb->seq);
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		txb->wire.type		= packet_type;
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		txb->wire.flags		= call->conn->out_clientflag;
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		txb->wire.userStatus	= 0;
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		txb->wire.securityIndex	= call->security_ix;
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		txb->wire._rsvd		= 0;
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		txb->wire.serviceId	= htons(call->dest_srx.srx_service);
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		trace_rxrpc_txbuf(txb->debug_id,
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				  txb->call_debug_id, txb->seq, 1,
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				  packet_type == RXRPC_PACKET_TYPE_DATA ?
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				  rxrpc_txbuf_alloc_data :
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				  rxrpc_txbuf_alloc_ack);
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		atomic_inc(&rxrpc_nr_txbuf);
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	}
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	return txb;
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}
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void rxrpc_get_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what)
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{
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	int r;
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	__refcount_inc(&txb->ref, &r);
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	trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, r + 1, what);
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}
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void rxrpc_see_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what)
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{
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	int r = refcount_read(&txb->ref);
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	trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, r, what);
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}
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static void rxrpc_free_txbuf(struct rcu_head *rcu)
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{
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	struct rxrpc_txbuf *txb = container_of(rcu, struct rxrpc_txbuf, rcu);
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	trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, 0,
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			  rxrpc_txbuf_free);
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	kfree(txb);
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	atomic_dec(&rxrpc_nr_txbuf);
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}
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void rxrpc_put_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what)
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{
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	unsigned int debug_id, call_debug_id;
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	rxrpc_seq_t seq;
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	bool dead;
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	int r;
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	if (txb) {
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		debug_id = txb->debug_id;
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		call_debug_id = txb->call_debug_id;
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		seq = txb->seq;
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		dead = __refcount_dec_and_test(&txb->ref, &r);
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		trace_rxrpc_txbuf(debug_id, call_debug_id, seq, r - 1, what);
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		if (dead)
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			call_rcu(&txb->rcu, rxrpc_free_txbuf);
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	}
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}
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/*
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 * Shrink the transmit buffer.
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 */
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void rxrpc_shrink_call_tx_buffer(struct rxrpc_call *call)
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{
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	struct rxrpc_txbuf *txb;
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	rxrpc_seq_t hard_ack = smp_load_acquire(&call->acks_hard_ack);
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	bool wake = false;
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	_enter("%x/%x/%x", call->tx_bottom, call->acks_hard_ack, call->tx_top);
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	while ((txb = list_first_entry_or_null(&call->tx_buffer,
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					       struct rxrpc_txbuf, call_link))) {
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		hard_ack = smp_load_acquire(&call->acks_hard_ack);
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		if (before(hard_ack, txb->seq))
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			break;
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		if (txb->seq != call->tx_bottom + 1)
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			rxrpc_see_txbuf(txb, rxrpc_txbuf_see_out_of_step);
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		ASSERTCMP(txb->seq, ==, call->tx_bottom + 1);
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		smp_store_release(&call->tx_bottom, call->tx_bottom + 1);
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		list_del_rcu(&txb->call_link);
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		trace_rxrpc_txqueue(call, rxrpc_txqueue_dequeue);
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		rxrpc_put_txbuf(txb, rxrpc_txbuf_put_rotated);
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		if (after(call->acks_hard_ack, call->tx_bottom + 128))
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			wake = true;
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	}
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	if (wake)
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		wake_up(&call->waitq);
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}
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