sctp: introduce struct sctp_stream_out_ext

With the stream schedulers, sctp_stream_out will become too big to be
allocated by kmalloc and as we need to allocate with BH disabled, we
cannot use __vmalloc in sctp_stream_init().

This patch moves out the stats from sctp_stream_out to
sctp_stream_out_ext, which will be allocated only when the application
tries to sendmsg something on it.

Just the introduction of sctp_stream_out_ext would already fix the issue
described above by splitting the allocation in two. Moving the stats
to it also reduces the pressure on the allocator as we will ask for less
memory atomically when creating the socket and we will use GFP_KERNEL
later.

Then, for stream schedulers, we will just use sctp_stream_out_ext.

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

4 files changed, 42 insertions, 11 deletions

diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
index 3afac275ee82..7b261afc47b9 100644
--- a/net/sctp/chunk.c
+++ b/net/sctp/chunk.c
@@ -311,10 +311,10 @@ int sctp_chunk_abandoned(struct sctp_chunk *chunk)
 
 		if (chunk->sent_count) {
 			chunk->asoc->abandoned_sent[SCTP_PR_INDEX(TTL)]++;
-			streamout->abandoned_sent[SCTP_PR_INDEX(TTL)]++;
+			streamout->ext->abandoned_sent[SCTP_PR_INDEX(TTL)]++;
 		} else {
 			chunk->asoc->abandoned_unsent[SCTP_PR_INDEX(TTL)]++;
-			streamout->abandoned_unsent[SCTP_PR_INDEX(TTL)]++;
+			streamout->ext->abandoned_unsent[SCTP_PR_INDEX(TTL)]++;
 		}
 		return 1;
 	} else if (SCTP_PR_RTX_ENABLED(chunk->sinfo.sinfo_flags) &&
@@ -323,7 +323,7 @@ int sctp_chunk_abandoned(struct sctp_chunk *chunk)
 			&chunk->asoc->stream.out[chunk->sinfo.sinfo_stream];
 
 		chunk->asoc->abandoned_sent[SCTP_PR_INDEX(RTX)]++;
-		streamout->abandoned_sent[SCTP_PR_INDEX(RTX)]++;
+		streamout->ext->abandoned_sent[SCTP_PR_INDEX(RTX)]++;
 		return 1;
 	} else if (!SCTP_PR_POLICY(chunk->sinfo.sinfo_flags) &&
 		   chunk->msg->expires_at &&
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 2966ff400755..746b07b7937d 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -366,7 +366,7 @@ static int sctp_prsctp_prune_sent(struct sctp_association *asoc,
 		streamout = &asoc->stream.out[chk->sinfo.sinfo_stream];
 		asoc->sent_cnt_removable--;
 		asoc->abandoned_sent[SCTP_PR_INDEX(PRIO)]++;
-		streamout->abandoned_sent[SCTP_PR_INDEX(PRIO)]++;
+		streamout->ext->abandoned_sent[SCTP_PR_INDEX(PRIO)]++;
 
 		if (!chk->tsn_gap_acked) {
 			if (chk->transport)
@@ -404,7 +404,7 @@ static int sctp_prsctp_prune_unsent(struct sctp_association *asoc,
 			struct sctp_stream_out *streamout =
 				&asoc->stream.out[chk->sinfo.sinfo_stream];
 
-			streamout->abandoned_unsent[SCTP_PR_INDEX(PRIO)]++;
+			streamout->ext->abandoned_unsent[SCTP_PR_INDEX(PRIO)]++;
 		}
 
 		msg_len -= SCTP_DATA_SNDSIZE(chk) +
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index d4730ada7f32..d207734326b0 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1927,6 +1927,13 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
 		goto out_free;
 	}
 
+	/* Allocate sctp_stream_out_ext if not already done */
+	if (unlikely(!asoc->stream.out[sinfo->sinfo_stream].ext)) {
+		err = sctp_stream_init_ext(&asoc->stream, sinfo->sinfo_stream);
+		if (err)
+			goto out_free;
+	}
+
 	if (sctp_wspace(asoc) < msg_len)
 		sctp_prsctp_prune(asoc, sinfo, msg_len - sctp_wspace(asoc));
 
@@ -6645,7 +6652,7 @@ static int sctp_getsockopt_pr_streamstatus(struct sock *sk, int len,
 					   char __user *optval,
 					   int __user *optlen)
 {
-	struct sctp_stream_out *streamout;
+	struct sctp_stream_out_ext *streamoute;
 	struct sctp_association *asoc;
 	struct sctp_prstatus params;
 	int retval = -EINVAL;
@@ -6668,21 +6675,29 @@ static int sctp_getsockopt_pr_streamstatus(struct sock *sk, int len,
 	if (!asoc || params.sprstat_sid >= asoc->stream.outcnt)
 		goto out;
 
-	streamout = &asoc->stream.out[params.sprstat_sid];
+	streamoute = asoc->stream.out[params.sprstat_sid].ext;
+	if (!streamoute) {
+		/* Not allocated yet, means all stats are 0 */
+		params.sprstat_abandoned_unsent = 0;
+		params.sprstat_abandoned_sent = 0;
+		retval = 0;
+		goto out;
+	}
+
 	if (policy == SCTP_PR_SCTP_NONE) {
 		params.sprstat_abandoned_unsent = 0;
 		params.sprstat_abandoned_sent = 0;
 		for (policy = 0; policy <= SCTP_PR_INDEX(MAX); policy++) {
 			params.sprstat_abandoned_unsent +=
-				streamout->abandoned_unsent[policy];
+				streamoute->abandoned_unsent[policy];
 			params.sprstat_abandoned_sent +=
-				streamout->abandoned_sent[policy];
+				streamoute->abandoned_sent[policy];
 		}
 	} else {
 		params.sprstat_abandoned_unsent =
-			streamout->abandoned_unsent[__SCTP_PR_INDEX(policy)];
+			streamoute->abandoned_unsent[__SCTP_PR_INDEX(policy)];
 		params.sprstat_abandoned_sent =
-			streamout->abandoned_sent[__SCTP_PR_INDEX(policy)];
+			streamoute->abandoned_sent[__SCTP_PR_INDEX(policy)];
 	}
 
 	if (put_user(len, optlen) || copy_to_user(optval, &params, len)) {
diff --git a/net/sctp/stream.c b/net/sctp/stream.c
index 952437d656cc..055ca25bbc91 100644
--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -121,8 +121,24 @@ in:
 	return 0;
 }
 
+int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid)
+{
+	struct sctp_stream_out_ext *soute;
+
+	soute = kzalloc(sizeof(*soute), GFP_KERNEL);
+	if (!soute)
+		return -ENOMEM;
+	stream->out[sid].ext = soute;
+
+	return 0;
+}
+
 void sctp_stream_free(struct sctp_stream *stream)
 {
+	int i;
+
+	for (i = 0; i < stream->outcnt; i++)
+		kfree(stream->out[i].ext);
 	kfree(stream->out);
 	kfree(stream->in);
 }