[PATCH net 1/5] rxrpc: Pass the input handler's data skb reference to the Rx ring

From: David Howells
Date: Thu Aug 29 2019 - 09:06:23 EST


Pass the reference held on a DATA skb in the rxrpc input handler into the
Rx ring rather than getting an additional ref for this and then dropping
the original ref at the end.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---

net/rxrpc/input.c | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 35b1a9368d80..140cede77655 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -422,7 +422,8 @@ static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
}

/*
- * Process a DATA packet, adding the packet to the Rx ring.
+ * Process a DATA packet, adding the packet to the Rx ring. The caller's
+ * packet ref must be passed on or discarded.
*/
static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
{
@@ -441,8 +442,10 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
sp->hdr.serial, seq0, sp->hdr.flags, sp->nr_subpackets);

state = READ_ONCE(call->state);
- if (state >= RXRPC_CALL_COMPLETE)
+ if (state >= RXRPC_CALL_COMPLETE) {
+ rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
return;
+ }

if (call->state == RXRPC_CALL_SERVER_RECV_REQUEST) {
unsigned long timo = READ_ONCE(call->next_req_timo);
@@ -555,7 +558,8 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
* Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
* and also rxrpc_fill_out_ack().
*/
- rxrpc_get_skb(skb, rxrpc_skb_rx_got);
+ if (!terminal)
+ rxrpc_get_skb(skb, rxrpc_skb_rx_got);
call->rxtx_annotations[ix] = annotation;
smp_wmb();
call->rxtx_buffer[ix] = skb;
@@ -616,6 +620,7 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)

unlock:
spin_unlock(&call->input_lock);
+ rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
_leave(" [queued]");
}

@@ -1024,7 +1029,7 @@ static void rxrpc_input_call_packet(struct rxrpc_call *call,
switch (sp->hdr.type) {
case RXRPC_PACKET_TYPE_DATA:
rxrpc_input_data(call, skb);
- break;
+ goto no_free;

case RXRPC_PACKET_TYPE_ACK:
rxrpc_input_ack(call, skb);
@@ -1051,6 +1056,8 @@ static void rxrpc_input_call_packet(struct rxrpc_call *call,
break;
}

+ rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
+no_free:
_leave("");
}

@@ -1375,8 +1382,11 @@ int rxrpc_input_packet(struct sock *udp_sk, struct sk_buff *skb)
mutex_unlock(&call->user_mutex);
}

+ /* Process a call packet; this either discards or passes on the ref
+ * elsewhere.
+ */
rxrpc_input_call_packet(call, skb);
- goto discard;
+ goto out;

discard:
rxrpc_free_skb(skb, rxrpc_skb_rx_freed);