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Subject[PATCH net 1/7] rxrpc: Improve jumbo packet counting
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Improve the information stored about jumbo packets so that we don't need to
reparse them so much later.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeffrey Altman <jaltman@auristor.com>
---

net/rxrpc/ar-internal.h | 10 +++++++---
net/rxrpc/input.c | 23 ++++++++++++++---------
net/rxrpc/protocol.h | 9 +++++++++
3 files changed, 30 insertions(+), 12 deletions(-)

diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 145335611af6..87cff6c218b6 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -185,11 +185,15 @@ struct rxrpc_host_header {
* - max 48 bytes (struct sk_buff::cb)
*/
struct rxrpc_skb_priv {
- union {
- u8 nr_jumbo; /* Number of jumbo subpackets */
- };
+ u8 nr_subpackets; /* Number of subpackets */
+ u8 rx_flags; /* Received packet flags */
+#define RXRPC_SKB_INCL_LAST 0x01 /* - Includes last packet */
union {
int remain; /* amount of space remaining for next write */
+
+ /* List of requested ACKs on subpackets */
+ unsigned long rx_req_ack[(RXRPC_MAX_NR_JUMBO + BITS_PER_LONG - 1) /
+ BITS_PER_LONG];
};

struct rxrpc_host_header hdr; /* RxRPC packet header from this packet */
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index dd47d465d1d3..ffcec5117954 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -347,7 +347,7 @@ static bool rxrpc_receiving_reply(struct rxrpc_call *call)
}

/*
- * Scan a jumbo packet to validate its structure and to work out how many
+ * Scan a data packet to validate its structure and to work out how many
* subpackets it contains.
*
* A jumbo packet is a collection of consecutive packets glued together with
@@ -358,16 +358,21 @@ static bool rxrpc_receiving_reply(struct rxrpc_call *call)
* the last are RXRPC_JUMBO_DATALEN in size. The last subpacket may be of any
* size.
*/
-static bool rxrpc_validate_jumbo(struct sk_buff *skb)
+static bool rxrpc_validate_data(struct sk_buff *skb)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
unsigned int offset = sizeof(struct rxrpc_wire_header);
unsigned int len = skb->len;
- int nr_jumbo = 1;
u8 flags = sp->hdr.flags;

- do {
- nr_jumbo++;
+ for (;;) {
+ if (flags & RXRPC_REQUEST_ACK)
+ __set_bit(sp->nr_subpackets, sp->rx_req_ack);
+ sp->nr_subpackets++;
+
+ if (!(flags & RXRPC_JUMBO_PACKET))
+ break;
+
if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
goto protocol_error;
if (flags & RXRPC_LAST_PACKET)
@@ -376,9 +381,10 @@ static bool rxrpc_validate_jumbo(struct sk_buff *skb)
if (skb_copy_bits(skb, offset, &flags, 1) < 0)
goto protocol_error;
offset += sizeof(struct rxrpc_jumbo_header);
- } while (flags & RXRPC_JUMBO_PACKET);
+ }

- sp->nr_jumbo = nr_jumbo;
+ if (flags & RXRPC_LAST_PACKET)
+ sp->rx_flags |= RXRPC_SKB_INCL_LAST;
return true;

protocol_error:
@@ -1237,8 +1243,7 @@ int rxrpc_input_packet(struct sock *udp_sk, struct sk_buff *skb)
if (sp->hdr.callNumber == 0 ||
sp->hdr.seq == 0)
goto bad_message;
- if (sp->hdr.flags & RXRPC_JUMBO_PACKET &&
- !rxrpc_validate_jumbo(skb))
+ if (!rxrpc_validate_data(skb))
goto bad_message;
break;

diff --git a/net/rxrpc/protocol.h b/net/rxrpc/protocol.h
index 99ce322d7caa..49bb972539aa 100644
--- a/net/rxrpc/protocol.h
+++ b/net/rxrpc/protocol.h
@@ -89,6 +89,15 @@ struct rxrpc_jumbo_header {
#define RXRPC_JUMBO_DATALEN 1412 /* non-terminal jumbo packet data length */
#define RXRPC_JUMBO_SUBPKTLEN (RXRPC_JUMBO_DATALEN + sizeof(struct rxrpc_jumbo_header))

+/*
+ * The maximum number of subpackets that can possibly fit in a UDP packet is:
+ *
+ * ((max_IP - IP_hdr - UDP_hdr) / RXRPC_JUMBO_SUBPKTLEN) + 1
+ * = ((65535 - 28 - 28) / 1416) + 1
+ * = 46 non-terminal packets and 1 terminal packet.
+ */
+#define RXRPC_MAX_NR_JUMBO 47
+
/*****************************************************************************/
/*
* on-the-wire Rx ACK packet data payload
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