sctp: count both sk and asoc sndbuf with skb truesize and sctp_chunk size

Now it's confusing that asoc sndbuf_used is doing memory accounting with
SCTP_DATA_SNDSIZE(chunk) + sizeof(sk_buff) + sizeof(sctp_chunk) while sk
sk_wmem_alloc is doing that with skb->truesize + sizeof(sctp_chunk).

It also causes sctp_prsctp_prune to count with a wrong freed memory when
sndbuf_policy is not set.

To make this right and also keep consistent between asoc sndbuf_used, sk
sk_wmem_alloc and sk_wmem_queued, use skb->truesize + sizeof(sctp_chunk)
for them.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 6 deletions

diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 42191ed9902b..9cb854b05342 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -385,9 +385,7 @@ static int sctp_prsctp_prune_sent(struct sctp_association *asoc,
                         asoc->outqueue.outstanding_bytes -= sctp_data_size(chk);
                 }
 
-                msg_len -= SCTP_DATA_SNDSIZE(chk) +
-                           sizeof(struct sk_buff) +
-                           sizeof(struct sctp_chunk);
+                msg_len -= chk->skb->truesize + sizeof(struct sctp_chunk);
                 if (msg_len <= 0)
                         break;
         }
@@ -421,9 +419,7 @@ static int sctp_prsctp_prune_unsent(struct sctp_association *asoc,
                         streamout->ext->abandoned_unsent[SCTP_PR_INDEX(PRIO)]++;
                 }
 
-                msg_len -= SCTP_DATA_SNDSIZE(chk) +
-                           sizeof(struct sk_buff) +
-                           sizeof(struct sctp_chunk);
+                msg_len -= chk->skb->truesize + sizeof(struct sctp_chunk);
                 sctp_chunk_free(chk);
                 if (msg_len <= 0)
                         break;