sctp: reduce memory footprint of sctp_chunk structure

sctp_chunks should be put on a diet.  This is some of the low hanging
fruit that we can strip out.  Changes all the __s8/__u8 flags to
bitfields.  Saves 12 bytes per chunk.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

4 files changed, 26 insertions, 23 deletions

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index ab1c472ea753..0dc1b7267c37 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -731,20 +731,23 @@ struct sctp_chunk {
          */
         struct sk_buff *auth_chunk;
 
-        __u8 rtt_in_progress;   /* Is this chunk used for RTT calculation? */
-        __u8 resent;            /* Has this chunk ever been retransmitted. */
-        __u8 has_tsn;           /* Does this chunk have a TSN yet? */
-        __u8 has_ssn;           /* Does this chunk have a SSN yet? */
-        __u8 singleton;         /* Was this the only chunk in the packet? */
-        __u8 end_of_packet;     /* Was this the last chunk in the packet? */
-        __u8 ecn_ce_done;       /* Have we processed the ECN CE bit? */
-        __u8 pdiscard;          /* Discard the whole packet now? */
-        __u8 tsn_gap_acked;     /* Is this chunk acked by a GAP ACK? */
-        __s8 fast_retransmit;    /* Is this chunk fast retransmitted? */
-        __u8 tsn_missing_report; /* Data chunk missing counter. */
-        __u8 data_accepted;     /* At least 1 chunk in this packet accepted */
-        __u8 auth;              /* IN: was auth'ed | OUT: needs auth */
-        __u8 has_asconf;        /* IN: have seen an asconf before */
+#define SCTP_CAN_FRTX 0x0
+#define SCTP_NEED_FRTX 0x1
+#define SCTP_DONT_FRTX 0x2
+        __u16   rtt_in_progress:1,      /* This chunk used for RTT calc? */
+                resent:1,               /* Has this chunk ever been resent. */
+                has_tsn:1,              /* Does this chunk have a TSN yet? */
+                has_ssn:1,              /* Does this chunk have a SSN yet? */
+                singleton:1,            /* Only chunk in the packet? */
+                end_of_packet:1,        /* Last chunk in the packet? */
+                ecn_ce_done:1,          /* Have we processed the ECN CE bit? */
+                pdiscard:1,             /* Discard the whole packet now? */
+                tsn_gap_acked:1,        /* Is this chunk acked by a GAP ACK? */
+                data_accepted:1,        /* At least 1 chunk accepted */
+                auth:1,                 /* IN: was auth'ed | OUT: needs auth */
+                has_asconf:1,           /* IN: have seen an asconf before */
+                tsn_missing_report:2,   /* Data chunk missing counter. */
+                fast_retransmit:2;      /* Is this chunk fast retransmitted? */
 };
 
 void sctp_chunk_hold(struct sctp_chunk *);
diff --git a/net/sctp/output.c b/net/sctp/output.c
index 225c7123c41f..c3f417f7ec6e 100644
--- a/net/sctp/output.c
+++ b/net/sctp/output.c
@@ -699,7 +699,7 @@ static sctp_xmit_t sctp_packet_append_data(struct sctp_packet *packet,
          *    When a Fast Retransmit is being performed the sender SHOULD
          *    ignore the value of cwnd and SHOULD NOT delay retransmission.
          */
-        if (chunk->fast_retransmit <= 0)
+        if (chunk->fast_retransmit != SCTP_NEED_FRTX)
                 if (transport->flight_size >= transport->cwnd) {
                         retval = SCTP_XMIT_RWND_FULL;
                         goto finish;
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index da8d846301c1..247ebc95c1e5 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -420,7 +420,7 @@ void sctp_retransmit_mark(struct sctp_outq *q,
                  * be added to the retransmit queue.
                  */
                 if ((reason == SCTP_RTXR_FAST_RTX  &&
-                            (chunk->fast_retransmit > 0)) ||
+                            (chunk->fast_retransmit == SCTP_NEED_FRTX)) ||
                     (reason != SCTP_RTXR_FAST_RTX  && !chunk->tsn_gap_acked)) {
                         /* If this chunk was sent less then 1 rto ago, do not
                          * retransmit this chunk, but give the peer time
@@ -650,8 +650,8 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
                         /* Mark the chunk as ineligible for fast retransmit
                          * after it is retransmitted.
                          */
-                        if (chunk->fast_retransmit > 0)
-                                chunk->fast_retransmit = -1;
+                        if (chunk->fast_retransmit == SCTP_NEED_FRTX)
+                                chunk->fast_retransmit = SCTP_DONT_FRTX;
 
                         /* Force start T3-rtx timer when fast retransmitting
                          * the earliest outstanding TSN
@@ -680,8 +680,8 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
          */
         if (rtx_timeout || fast_rtx) {
                 list_for_each_entry(chunk1, lqueue, transmitted_list) {
-                        if (chunk1->fast_retransmit > 0)
-                                chunk1->fast_retransmit = -1;
+                        if (chunk1->fast_retransmit == SCTP_NEED_FRTX)
+                                chunk1->fast_retransmit = SCTP_DONT_FRTX;
                 }
         }
 
@@ -1656,7 +1656,7 @@ static void sctp_mark_missing(struct sctp_outq *q,
                  * chunk if it has NOT been fast retransmitted or marked for
                  * fast retransmit already.
                  */
-                if (!chunk->fast_retransmit &&
+                if (chunk->fast_retransmit == SCTP_CAN_FRTX &&
                     !chunk->tsn_gap_acked &&
                     TSN_lt(tsn, highest_new_tsn_in_sack)) {
 
@@ -1681,7 +1681,7 @@ static void sctp_mark_missing(struct sctp_outq *q,
                  */
 
                 if (chunk->tsn_missing_report >= 3) {
-                        chunk->fast_retransmit = 1;
+                        chunk->fast_retransmit = SCTP_NEED_FRTX;
                         do_fast_retransmit = 1;
                 }
         }
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index d68869f966c3..99fe0747cc96 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -1211,7 +1211,7 @@ struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
          */
         retval->tsn_missing_report = 0;
         retval->tsn_gap_acked = 0;
-        retval->fast_retransmit = 0;
+        retval->fast_retransmit = SCTP_CAN_FRTX;
 
         /* If this is a fragmented message, track all fragments
          * of the message (for SEND_FAILED).