sctp: implement memory accounting on rx path

sk_forward_alloc's updating is also done on rx path, but to be consistent
we change to use sk_mem_charge() in sctp_skb_set_owner_r().

In sctp_eat_data(), it's not enough to check sctp_memory_pressure only,
which doesn't work for mem_cgroup_sockets_enabled, so we change to use
sk_under_memory_pressure().

When it's under memory pressure, sk_mem_reclaim() and sk_rmem_schedule()
should be called on both RENEGE or CHUNK DELIVERY path exit the memory
pressure status as soon as possible.

Note that sk_rmem_schedule() is using datalen to make things easy there.

Reported-by: Matteo Croce <mcroce@redhat.com>
Tested-by: Matteo Croce <mcroce@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 15 insertions, 15 deletions

diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index 1d13ec3f2707..eefdfa5abf6e 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -421,7 +421,7 @@ static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
         /*
          * This mimics the behavior of skb_set_owner_r
          */
-        sk->sk_forward_alloc -= event->rmem_len;
+        sk_mem_charge(sk, event->rmem_len);
 }
 
 /* Tests if the list has one and only one entry. */
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index c9ae3404b1bb..7dfc34b28f4f 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -6412,13 +6412,15 @@ static int sctp_eat_data(const struct sctp_association *asoc,
          * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
          * memory usage too much
          */
-        if (*sk->sk_prot_creator->memory_pressure) {
+        if (sk_under_memory_pressure(sk)) {
                 if (sctp_tsnmap_has_gap(map) &&
                     (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
                         pr_debug("%s: under pressure, reneging for tsn:%u\n",
                                  __func__, tsn);
                         deliver = SCTP_CMD_RENEGE;
-                 }
+                } else {
+                        sk_mem_reclaim(sk);
+                }
         }
 
         /*
diff --git a/net/sctp/ulpevent.c b/net/sctp/ulpevent.c
index 8cb7d9858270..c2a7478587ab 100644
--- a/net/sctp/ulpevent.c
+++ b/net/sctp/ulpevent.c
@@ -634,8 +634,9 @@ struct sctp_ulpevent *sctp_ulpevent_make_rcvmsg(struct sctp_association *asoc,
                                                 gfp_t gfp)
 {
         struct sctp_ulpevent *event = NULL;
-        struct sk_buff *skb;
-        size_t padding, len;
+        struct sk_buff *skb = chunk->skb;
+        struct sock *sk = asoc->base.sk;
+        size_t padding, datalen;
         int rx_count;
 
         /*
@@ -646,15 +647,12 @@ struct sctp_ulpevent *sctp_ulpevent_make_rcvmsg(struct sctp_association *asoc,
         if (asoc->ep->rcvbuf_policy)
                 rx_count = atomic_read(&asoc->rmem_alloc);
         else
-                rx_count = atomic_read(&asoc->base.sk->sk_rmem_alloc);
+                rx_count = atomic_read(&sk->sk_rmem_alloc);
 
-        if (rx_count >= asoc->base.sk->sk_rcvbuf) {
+        datalen = ntohs(chunk->chunk_hdr->length);
 
-                if ((asoc->base.sk->sk_userlocks & SOCK_RCVBUF_LOCK) ||
-                    (!sk_rmem_schedule(asoc->base.sk, chunk->skb,
-                                       chunk->skb->truesize)))
-                        goto fail;
-        }
+        if (rx_count >= sk->sk_rcvbuf || !sk_rmem_schedule(sk, skb, datalen))
+                goto fail;
 
         /* Clone the original skb, sharing the data.  */
         skb = skb_clone(chunk->skb, gfp);
@@ -681,8 +679,7 @@ struct sctp_ulpevent *sctp_ulpevent_make_rcvmsg(struct sctp_association *asoc,
          * The sender should never pad with more than 3 bytes.  The receiver
          * MUST ignore the padding bytes.
          */
-        len = ntohs(chunk->chunk_hdr->length);
-        padding = SCTP_PAD4(len) - len;
+        padding = SCTP_PAD4(datalen) - datalen;
 
         /* Fixup cloned skb with just this chunks data.  */
         skb_trim(skb, chunk->chunk_end - padding - skb->data);
diff --git a/net/sctp/ulpqueue.c b/net/sctp/ulpqueue.c
index 7cdc3623fa35..a212fe079c07 100644
--- a/net/sctp/ulpqueue.c
+++ b/net/sctp/ulpqueue.c
@@ -1104,7 +1104,8 @@ void sctp_ulpq_renege(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
                         freed += sctp_ulpq_renege_frags(ulpq, needed - freed);
         }
         /* If able to free enough room, accept this chunk. */
-        if (freed >= needed) {
+        if (sk_rmem_schedule(asoc->base.sk, chunk->skb, needed) &&
+            freed >= needed) {
                 int retval = sctp_ulpq_tail_data(ulpq, chunk, gfp);
                 /*
                  * Enter partial delivery if chunk has not been