[PATCH net-next 17/17] rxrpc: Simplify skbuff accounting in receive path
From: David Howells
Date: Wed Nov 23 2022 - 05:35:33 EST
A received skbuff needs a ref when it gets put on a call data queue or conn
packet queue, and rxrpc_input_packet() and co. jump through a lot of hoops
to avoid double-dropping the skbuff ref so that we can avoid getting a ref
when we queue the packet.
Change this so that the skbuff ref is unconditionally dropped by the caller
of rxrpc_input_packet(). An additional ref is then taken on the packet if
it is pushed onto a queue.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
cc: linux-afs@xxxxxxxxxxxxxxxxxxx
---
include/trace/events/rxrpc.h | 1 -
net/rxrpc/conn_event.c | 5 +----
net/rxrpc/input.c | 38 +++++++++++++++++++-------------------
net/rxrpc/io_thread.c | 40 ++++++++++++++++------------------------
net/rxrpc/output.c | 6 +-----
5 files changed, 37 insertions(+), 53 deletions(-)
diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index 3ecacc12fe90..33fb8d2a4de6 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -37,7 +37,6 @@
EM(rxrpc_skb_put_error_report, "PUT error-rep") \
EM(rxrpc_skb_put_input, "PUT input ") \
EM(rxrpc_skb_put_jumbo_subpacket, "PUT jumbo-sub") \
- EM(rxrpc_skb_put_lose, "PUT lose ") \
EM(rxrpc_skb_put_purge, "PUT purge ") \
EM(rxrpc_skb_put_rotate, "PUT rotate ") \
EM(rxrpc_skb_put_unknown, "PUT unknown ") \
diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index 6f376e4e94bc..78f91303a4a8 100644
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -494,6 +494,7 @@ static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
{
_enter("%p,%p", conn, skb);
+ rxrpc_get_skb(skb, rxrpc_skb_get_conn_work);
skb_queue_tail(&conn->rx_queue, skb);
rxrpc_queue_conn(conn, rxrpc_conn_queue_rx_work);
}
@@ -517,12 +518,10 @@ int rxrpc_input_conn_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
case RXRPC_PACKET_TYPE_ACK:
rxrpc_conn_retransmit_call(conn, skb,
sp->hdr.cid & RXRPC_CHANNELMASK);
- rxrpc_free_skb(skb, rxrpc_skb_put_input);
return 0;
case RXRPC_PACKET_TYPE_BUSY:
/* Just ignore BUSY packets for now. */
- rxrpc_free_skb(skb, rxrpc_skb_put_input);
return 0;
case RXRPC_PACKET_TYPE_ABORT:
@@ -531,7 +530,6 @@ int rxrpc_input_conn_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
conn->state = RXRPC_CONN_REMOTELY_ABORTED;
set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
rxrpc_abort_calls(conn, RXRPC_CALL_REMOTELY_ABORTED, sp->hdr.serial);
- rxrpc_free_skb(skb, rxrpc_skb_put_input);
return -ECONNABORTED;
case RXRPC_PACKET_TYPE_CHALLENGE:
@@ -542,7 +540,6 @@ int rxrpc_input_conn_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
default:
trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
tracepoint_string("bad_conn_pkt"));
- rxrpc_free_skb(skb, rxrpc_skb_put_input);
return -EPROTO;
}
}
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index f5a3b1e4f284..70f54976c820 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -344,7 +344,8 @@ static void rxrpc_input_queue_data(struct rxrpc_call *call, struct sk_buff *skb,
/*
* Process a DATA packet.
*/
-static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb)
+static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb,
+ bool *_notify)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
struct sk_buff *oos;
@@ -367,7 +368,7 @@ static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb)
if (test_and_set_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
seq + 1 != wtop) {
rxrpc_proto_abort("LSN", call, seq);
- goto err_free;
+ return;
}
} else {
if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
@@ -375,7 +376,7 @@ static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb)
pr_warn("Packet beyond last: c=%x q=%x window=%x-%x wlimit=%x\n",
call->debug_id, seq, window, wtop, wlimit);
rxrpc_proto_abort("LSA", call, seq);
- goto err_free;
+ return;
}
}
@@ -410,9 +411,11 @@ static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb)
if (after(window, wtop))
wtop = window;
+ rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg);
+
spin_lock(&call->recvmsg_queue.lock);
rxrpc_input_queue_data(call, skb, window, wtop, rxrpc_receive_queue);
- skb = NULL;
+ *_notify = true;
while ((oos = skb_peek(&call->rx_oos_queue))) {
struct rxrpc_skb_priv *osp = rxrpc_skb(oos);
@@ -464,16 +467,17 @@ static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb)
struct rxrpc_skb_priv *osp = rxrpc_skb(oos);
if (after(osp->hdr.seq, seq)) {
+ rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg_oos);
__skb_queue_before(&call->rx_oos_queue, oos, skb);
goto oos_queued;
}
}
+ rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg_oos);
__skb_queue_tail(&call->rx_oos_queue, skb);
oos_queued:
trace_rxrpc_receive(call, last ? rxrpc_receive_oos_last : rxrpc_receive_oos,
sp->hdr.serial, sp->hdr.seq);
- skb = NULL;
}
send_ack:
@@ -483,9 +487,6 @@ static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb)
else
rxrpc_propose_delay_ACK(call, serial,
rxrpc_propose_ack_input_data);
-
-err_free:
- rxrpc_free_skb(skb, rxrpc_skb_put_input);
}
/*
@@ -498,6 +499,7 @@ static bool rxrpc_input_split_jumbo(struct rxrpc_call *call, struct sk_buff *skb
struct sk_buff *jskb;
unsigned int offset = sizeof(struct rxrpc_wire_header);
unsigned int len = skb->len - offset;
+ bool notify = false;
while (sp->hdr.flags & RXRPC_JUMBO_PACKET) {
if (len < RXRPC_JUMBO_SUBPKTLEN)
@@ -517,7 +519,8 @@ static bool rxrpc_input_split_jumbo(struct rxrpc_call *call, struct sk_buff *skb
jsp = rxrpc_skb(jskb);
jsp->offset = offset;
jsp->len = RXRPC_JUMBO_DATALEN;
- rxrpc_input_data_one(call, jskb);
+ rxrpc_input_data_one(call, jskb, ¬ify);
+ rxrpc_free_skb(jskb, rxrpc_skb_put_jumbo_subpacket);
sp->hdr.flags = jhdr.flags;
sp->hdr._rsvd = ntohs(jhdr._rsvd);
@@ -529,7 +532,11 @@ static bool rxrpc_input_split_jumbo(struct rxrpc_call *call, struct sk_buff *skb
sp->offset = offset;
sp->len = len;
- rxrpc_input_data_one(call, skb);
+ rxrpc_input_data_one(call, skb, ¬ify);
+ if (notify) {
+ trace_rxrpc_notify_socket(call->debug_id, sp->hdr.serial);
+ rxrpc_notify_socket(call);
+ }
return true;
protocol_error:
@@ -553,7 +560,7 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
state = READ_ONCE(call->state);
if (state >= RXRPC_CALL_COMPLETE)
- goto out;
+ return;
/* Unshare the packet so that it can be modified for in-place
* decryption.
@@ -603,9 +610,6 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
out_notify:
trace_rxrpc_notify_socket(call->debug_id, serial);
rxrpc_notify_socket(call);
-out:
- rxrpc_free_skb(skb, rxrpc_skb_put_input);
- _leave(" [queued]");
}
/*
@@ -975,7 +979,7 @@ void rxrpc_input_call_packet(struct rxrpc_call *call, struct sk_buff *skb)
switch (sp->hdr.type) {
case RXRPC_PACKET_TYPE_DATA:
rxrpc_input_data(call, skb);
- goto no_free;
+ break;
case RXRPC_PACKET_TYPE_ACK:
rxrpc_input_ack(call, skb);
@@ -999,10 +1003,6 @@ void rxrpc_input_call_packet(struct rxrpc_call *call, struct sk_buff *skb)
default:
break;
}
-
- rxrpc_free_skb(skb, rxrpc_skb_put_input);
-no_free:
- _leave("");
}
/*
diff --git a/net/rxrpc/io_thread.c b/net/rxrpc/io_thread.c
index fbb809967bf1..1ea39ff33841 100644
--- a/net/rxrpc/io_thread.c
+++ b/net/rxrpc/io_thread.c
@@ -77,8 +77,6 @@ static void rxrpc_input_version(struct rxrpc_local *local, struct sk_buff *skb)
if (v == 0)
rxrpc_send_version_request(local, &sp->hdr, skb);
}
-
- rxrpc_free_skb(skb, rxrpc_skb_put_input);
}
/*
@@ -150,7 +148,6 @@ static int rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff *skb)
static int lose;
if ((lose++ & 7) == 7) {
trace_rxrpc_rx_lose(sp);
- rxrpc_free_skb(skb, rxrpc_skb_put_lose);
return 0;
}
}
@@ -160,13 +157,13 @@ static int rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff *skb)
switch (sp->hdr.type) {
case RXRPC_PACKET_TYPE_VERSION:
if (rxrpc_to_client(sp))
- goto discard;
+ return 0;
rxrpc_input_version(local, skb);
- goto out;
+ return 0;
case RXRPC_PACKET_TYPE_BUSY:
if (rxrpc_to_server(sp))
- goto discard;
+ return 0;
fallthrough;
case RXRPC_PACKET_TYPE_ACK:
case RXRPC_PACKET_TYPE_ACKALL:
@@ -186,18 +183,18 @@ static int rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff *skb)
case RXRPC_PACKET_TYPE_CHALLENGE:
if (rxrpc_to_server(sp))
- goto discard;
+ return 0;
break;
case RXRPC_PACKET_TYPE_RESPONSE:
if (rxrpc_to_client(sp))
- goto discard;
+ return 0;
break;
/* Packet types 9-11 should just be ignored. */
case RXRPC_PACKET_TYPE_PARAMS:
case RXRPC_PACKET_TYPE_10:
case RXRPC_PACKET_TYPE_11:
- goto discard;
+ return 0;
default:
goto bad_message;
@@ -217,7 +214,7 @@ static int rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff *skb)
if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
sp->hdr.seq == 1)
goto unsupported_service;
- goto discard;
+ return 0;
}
}
@@ -243,7 +240,7 @@ static int rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff *skb)
/* Connection-level packet */
_debug("CONN %p {%d}", conn, conn->debug_id);
rxrpc_input_conn_packet(conn, skb);
- goto out;
+ return 0;
}
if ((int)sp->hdr.serial - (int)conn->hi_serial > 0)
@@ -255,19 +252,19 @@ static int rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff *skb)
/* Ignore really old calls */
if (sp->hdr.callNumber < chan->last_call)
- goto discard;
+ return 0;
if (sp->hdr.callNumber == chan->last_call) {
if (chan->call ||
sp->hdr.type == RXRPC_PACKET_TYPE_ABORT)
- goto discard;
+ return 0;
/* For the previous service call, if completed
* successfully, we discard all further packets.
*/
if (rxrpc_conn_is_service(conn) &&
chan->last_type == RXRPC_PACKET_TYPE_ACK)
- goto discard;
+ return 0;
/* But otherwise we need to retransmit the final packet
* from data cached in the connection record.
@@ -278,7 +275,7 @@ static int rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff *skb)
sp->hdr.serial,
sp->hdr.flags);
rxrpc_input_conn_packet(conn, skb);
- goto out;
+ return 0;
}
call = rcu_dereference(chan->call);
@@ -299,7 +296,7 @@ static int rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff *skb)
sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
goto bad_message;
if (sp->hdr.seq != 1)
- goto discard;
+ return 0;
call = rxrpc_new_incoming_call(local, rx, skb);
if (!call)
goto reject_packet;
@@ -313,12 +310,6 @@ static int rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff *skb)
rcu_read_unlock();
rxrpc_input_call_event(call, skb);
rcu_read_lock();
- goto out;
-
-discard:
- rxrpc_free_skb(skb, rxrpc_skb_put_input);
-out:
- trace_rxrpc_rx_done(0, 0);
return 0;
wrong_security:
@@ -346,9 +337,7 @@ static int rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff *skb)
post_abort:
skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
reject_packet:
- trace_rxrpc_rx_done(skb->mark, skb->priority);
rxrpc_reject_packet(local, skb);
- _leave(" [badmsg]");
return 0;
}
@@ -387,9 +376,12 @@ int rxrpc_io_thread(void *data)
if ((skb = __skb_dequeue(&rx_queue))) {
switch (skb->mark) {
case RXRPC_SKB_MARK_PACKET:
+ skb->priority = 0;
rcu_read_lock();
rxrpc_input_packet(local, skb);
rcu_read_unlock();
+ trace_rxrpc_rx_done(skb->mark, skb->priority);
+ rxrpc_free_skb(skb, rxrpc_skb_put_input);
break;
case RXRPC_SKB_MARK_ERROR:
rxrpc_input_error(local, skb);
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 9eb877f90433..0b5159dff995 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -585,7 +585,7 @@ void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
ioc = 2;
break;
default:
- goto out;
+ return;
}
if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
@@ -608,10 +608,6 @@ void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
trace_rxrpc_tx_packet(local->debug_id, &whdr,
rxrpc_tx_point_reject);
}
-
-out:
- rxrpc_free_skb(skb, rxrpc_skb_put_input);
- _leave("");
}
/*