sctp: introduce sctp_assoc_update_frag_point

and avoid the open-coded versions of it.

Now sctp_datamsg_from_user can just re-use asoc->frag_point as it will
always be updated.

Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 20 insertions, 39 deletions

diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index 0b98e4683f10..350c65620a4e 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -428,26 +428,6 @@ static inline int sctp_list_single_entry(struct list_head *head)
         return (head->next != head) && (head->next == head->prev);
 }
 
-/* Break down data chunks at this point.  */
-static inline int sctp_frag_point(const struct sctp_association *asoc, int pmtu)
-{
-        struct sctp_sock *sp = sctp_sk(asoc->base.sk);
-        struct sctp_af *af = sp->pf->af;
-        int frag = pmtu;
-
-        frag -= af->ip_options_len(asoc->base.sk);
-        frag -= af->net_header_len;
-        frag -= sizeof(struct sctphdr) + sctp_datachk_len(&asoc->stream);
-
-        if (asoc->user_frag)
-                frag = min_t(int, frag, asoc->user_frag);
-
-        frag = SCTP_TRUNC4(min_t(int, frag, SCTP_MAX_CHUNK_LEN -
-                                            sctp_datachk_len(&asoc->stream)));
-
-        return frag;
-}
-
 static inline void sctp_assoc_pending_pmtu(struct sctp_association *asoc)
 {
         sctp_assoc_sync_pmtu(asoc);
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index c5e244be8f1e..ebf809eed33a 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -2097,6 +2097,7 @@ int sctp_assoc_update(struct sctp_association *old,
 
 __u32 sctp_association_get_next_tsn(struct sctp_association *);
 
+void sctp_assoc_update_frag_point(struct sctp_association *asoc);
 void sctp_assoc_set_pmtu(struct sctp_association *asoc, __u32 pmtu);
 void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index 85b362324084..a29025418b96 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -666,8 +666,6 @@ struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
 
         peer->pmtu_pending = 0;
 
-        asoc->frag_point = sctp_frag_point(asoc, asoc->pathmtu);
-
         /* The asoc->peer.port might not be meaningful yet, but
          * initialize the packet structure anyway.
          */
@@ -1370,10 +1368,26 @@ sctp_assoc_choose_alter_transport(struct sctp_association *asoc,
         }
 }
 
+void sctp_assoc_update_frag_point(struct sctp_association *asoc)
+{
+        int frag = sctp_mtu_payload(sctp_sk(asoc->base.sk), asoc->pathmtu,
+                                    sctp_datachk_len(&asoc->stream));
+
+        if (asoc->user_frag)
+                frag = min_t(int, frag, asoc->user_frag);
+
+        frag = min_t(int, frag, SCTP_MAX_CHUNK_LEN -
+                                sctp_datachk_len(&asoc->stream));
+
+        asoc->frag_point = SCTP_TRUNC4(frag);
+}
+
 void sctp_assoc_set_pmtu(struct sctp_association *asoc, __u32 pmtu)
 {
-        if (asoc->pathmtu != pmtu)
+        if (asoc->pathmtu != pmtu) {
                 asoc->pathmtu = pmtu;
+                sctp_assoc_update_frag_point(asoc);
+        }
 
         pr_debug("%s: asoc:%p, pmtu:%d, frag_point:%d\n", __func__, asoc,
                  asoc->pathmtu, asoc->frag_point);
@@ -1403,10 +1417,6 @@ void sctp_assoc_sync_pmtu(struct sctp_association *asoc)
         }
 
         sctp_assoc_set_pmtu(asoc, pmtu);
-        asoc->frag_point = sctp_frag_point(asoc, pmtu);
-
-        pr_debug("%s: asoc:%p, pmtu:%d, frag_point:%d\n", __func__, asoc,
-                 asoc->pathmtu, asoc->frag_point);
 }
 
 /* Should we send a SACK to update our peer? */
diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
index be296d633e95..79daa98208c3 100644
--- a/net/sctp/chunk.c
+++ b/net/sctp/chunk.c
@@ -172,8 +172,6 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
         struct list_head *pos, *temp;
         struct sctp_chunk *chunk;
         struct sctp_datamsg *msg;
-        struct sctp_sock *sp;
-        struct sctp_af *af;
         int err;
 
         msg = sctp_datamsg_new(GFP_KERNEL);
@@ -192,12 +190,7 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
         /* This is the biggest possible DATA chunk that can fit into
          * the packet
          */
-        sp = sctp_sk(asoc->base.sk);
-        af = sp->pf->af;
-        max_data = asoc->pathmtu - af->net_header_len -
-                   sizeof(struct sctphdr) - sctp_datachk_len(&asoc->stream) -
-                   af->ip_options_len(asoc->base.sk);
-        max_data = SCTP_TRUNC4(max_data);
+        max_data = asoc->frag_point;
 
         /* If the the peer requested that we authenticate DATA chunks
          * we need to account for bundling of the AUTH chunks along with
@@ -222,9 +215,6 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
                 }
         }
 
-        /* Check what's our max considering the above */
-        max_data = min_t(size_t, max_data, asoc->frag_point);
-
         /* Set first_len and then account for possible bundles on first frag */
         first_len = max_data;
 
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index b9d14f57146b..21bf457be3ea 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3251,7 +3251,7 @@ static int sctp_setsockopt_maxseg(struct sock *sk, char __user *optval, unsigned
                                sctp_datachk_len(&asoc->stream);
                 }
                 asoc->user_frag = val;
-                asoc->frag_point = sctp_frag_point(asoc, asoc->pathmtu);
+                sctp_assoc_update_frag_point(asoc);
         } else {
                 if (params.assoc_id && sctp_style(sk, UDP))
                         return -EINVAL;