[PATCH net-next 22/36] rxrpc: Remove call->input_lock

From: David Howells <dhowells@redhat.com>
To: netdev@vger.kernel.org
Cc: Marc Dionne <marc.dionne@auristor.com>,
	linux-afs@lists.infradead.org, dhowells@redhat.com,
	linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH net-next 22/36] rxrpc: Remove call->input_lock
Date: Fri, 02 Dec 2022 00:18:10 +0000	[thread overview]
Message-ID: <166994029030.1732290.5887725366099476952.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <166994010342.1732290.13771061038178613124.stgit@warthog.procyon.org.uk>

Remove call->input_lock as it was only necessary to serialise access to the
state stored in the rxrpc_call struct by simultaneous softirq handlers
presenting received packets.  They now dump the packets in a queue and a
single process-context handler now processes them.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
---

 net/rxrpc/ar-internal.h |    1 -
 net/rxrpc/call_object.c |    1 -
 net/rxrpc/input.c       |   22 +++++-----------------
 3 files changed, 5 insertions(+), 19 deletions(-)

diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 566377c64184..654e9dab107c 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -657,7 +657,6 @@ struct rxrpc_call {
 	rxrpc_seq_t		rx_consumed;	/* Highest packet consumed */
 	rxrpc_serial_t		rx_serial;	/* Highest serial received for this call */
 	u8			rx_winsize;	/* Size of Rx window */
-	spinlock_t		input_lock;	/* Lock for packet input to this call */
 
 	/* TCP-style slow-start congestion control [RFC5681].  Since the SMSS
 	 * is fixed, we keep these numbers in terms of segments (ie. DATA
diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index 57c8d4cc900a..f6d1b3a6f8c6 100644
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -143,7 +143,6 @@ struct rxrpc_call *rxrpc_alloc_call(struct rxrpc_sock *rx, gfp_t gfp,
 	init_waitqueue_head(&call->waitq);
 	spin_lock_init(&call->notify_lock);
 	spin_lock_init(&call->tx_lock);
-	spin_lock_init(&call->input_lock);
 	spin_lock_init(&call->acks_ack_lock);
 	rwlock_init(&call->state_lock);
 	refcount_set(&call->ref, 1);
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index f4f6f3c62d03..13c52145a926 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -588,8 +588,6 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
 		}
 	}
 
-	spin_lock(&call->input_lock);
-
 	/* Received data implicitly ACKs all of the request packets we sent
 	 * when we're acting as a client.
 	 */
@@ -607,8 +605,6 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
 out:
 	trace_rxrpc_notify_socket(call->debug_id, serial);
 	rxrpc_notify_socket(call);
-
-	spin_unlock(&call->input_lock);
 	rxrpc_free_skb(skb, rxrpc_skb_put_input);
 	_leave(" [queued]");
 }
@@ -811,7 +807,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 	offset = sizeof(struct rxrpc_wire_header);
 	if (skb_copy_bits(skb, offset, &ack, sizeof(ack)) < 0) {
 		rxrpc_proto_abort("XAK", call, 0);
-		goto out_not_locked;
+		goto out;
 	}
 	offset += sizeof(ack);
 
@@ -863,7 +859,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 	    rxrpc_is_client_call(call)) {
 		rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 					  0, -ENETRESET);
-		return;
+		goto out;
 	}
 
 	/* If we get an OUT_OF_SEQUENCE ACK from the server, that can also
@@ -877,7 +873,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 	    rxrpc_is_client_call(call)) {
 		rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 					  0, -ENETRESET);
-		return;
+		goto out;
 	}
 
 	/* Discard any out-of-order or duplicate ACKs (outside lock). */
@@ -885,7 +881,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 		trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
 					   first_soft_ack, call->acks_first_seq,
 					   prev_pkt, call->acks_prev_seq);
-		goto out_not_locked;
+		goto out;
 	}
 
 	info.rxMTU = 0;
@@ -893,14 +889,12 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 	if (skb->len >= ioffset + sizeof(info) &&
 	    skb_copy_bits(skb, ioffset, &info, sizeof(info)) < 0) {
 		rxrpc_proto_abort("XAI", call, 0);
-		goto out_not_locked;
+		goto out;
 	}
 
 	if (nr_acks > 0)
 		skb_condense(skb);
 
-	spin_lock(&call->input_lock);
-
 	/* Discard any out-of-order or duplicate ACKs (inside lock). */
 	if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) {
 		trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
@@ -992,8 +986,6 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 
 	rxrpc_congestion_management(call, skb, &summary, acked_serial);
 out:
-	spin_unlock(&call->input_lock);
-out_not_locked:
 	rxrpc_free_skb(skb_put, rxrpc_skb_put_input);
 	rxrpc_free_skb(skb_old, rxrpc_skb_put_ack);
 }
@@ -1005,12 +997,8 @@ static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 {
 	struct rxrpc_ack_summary summary = { 0 };
 
-	spin_lock(&call->input_lock);
-
 	if (rxrpc_rotate_tx_window(call, call->tx_top, &summary))
 		rxrpc_end_tx_phase(call, false, "ETL");
-
-	spin_unlock(&call->input_lock);
 }
 
 /*


