[PATCH 5.4 13/19] sctp: shrink stream outq only when new outcnt < old outcnt

Greg Kroah-Hartman
2020-07-30T08:05:52Z

From: Xin Long <lucien.xin@gmail.com>

[ Upstream commit 8f13399db22f909a35735bf8ae2f932e0c8f0e30 ]

It's not necessary to go list_for_each for outq->out_chunk_list
when new outcnt >= old outcnt, as no chunk with higher sid than
new (outcnt - 1) exists in the outqueue.

While at it, also move the list_for_each code in a new function
sctp_stream_shrink_out(), which will be used in the next patch.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/sctp/stream.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)

--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -22,17 +22,11 @@
#include <net/sctp/sm.h>
#include <net/sctp/stream_sched.h>

-/* Migrates chunks from stream queues to new stream queues if needed,
- * but not across associations. Also, removes those chunks to streams
- * higher than the new max.
- */
-static void sctp_stream_outq_migrate(struct sctp_stream *stream,
- struct sctp_stream *new, __u16 outcnt)
+static void sctp_stream_shrink_out(struct sctp_stream *stream, __u16 outcnt)
{
struct sctp_association *asoc;
struct sctp_chunk *ch, *temp;
struct sctp_outq *outq;
- int i;

asoc = container_of(stream, struct sctp_association, stream);
outq = &asoc->outqueue;
@@ -56,6 +50,19 @@ static void sctp_stream_outq_migrate(str

sctp_chunk_free(ch);
}
+}
+
+/* Migrates chunks from stream queues to new stream queues if needed,
+ * but not across associations. Also, removes those chunks to streams
+ * higher than the new max.
+ */
+static void sctp_stream_outq_migrate(struct sctp_stream *stream,
+ struct sctp_stream *new, __u16 outcnt)
+{
+ int i;
+
+ if (stream->outcnt > outcnt)
+ sctp_stream_shrink_out(stream, outcnt);

if (new) {
/* Here we actually move the old ext stuff into the new