[DCCP]: Simplified conditions due to use of enum:8 states

This reaps the benefit of the earlier patch, which changed the type of
CCID 3 states to use enums, in that many conditions are now simplified
and the number of possible (unexpected) values is greatly reduced.

In a few instances, this also allowed to simplify pre-conditions; where
care has been taken to retain logical equivalence.

[DCCP]: Introduce a consistent BUG/WARN message scheme

This refines the existing set of DCCP messages so that
 * BUG(), BUG_ON(), WARN_ON() have meaningful DCCP-specific counterparts
 * DCCP_CRIT (for severe warnings) is not rate-limited
 * DCCP_WARN() is introduced as rate-limited wrapper

Using these allows a faster and cleaner transition to their original
counterparts once the code has matured into a full DCCP implementation.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

4 files changed, 63 insertions, 84 deletions

diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
index 0fb0d66544a2..207f7f9b36ca 100644
--- a/net/dccp/ccids/ccid2.c
+++ b/net/dccp/ccids/ccid2.c
@@ -420,7 +420,7 @@ static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset,
         return -1;
 
 out_invalid_option:
-        BUG_ON(1); /* should never happen... options were previously parsed ! */
+        DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
         return -1;
 }
 
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 7db801ec1ab9..4eada515b773 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -176,8 +176,6 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
                        ccid3_tx_state_name(hctx->ccid3hctx_state));
         
         switch (hctx->ccid3hctx_state) {
-        case TFRC_SSTATE_TERM:
-                goto out;
         case TFRC_SSTATE_NO_FBACK:
                 /* Halve send rate */
                 hctx->ccid3hctx_x /= 2;
@@ -240,9 +238,10 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
                                         2 * usecs_div(hctx->ccid3hctx_s,
                                                       hctx->ccid3hctx_x));
                 break;
-        default:
-                DCCP_BUG("%s, sk=%p, Illegal state (%d)!", dccp_role(sk), sk,
-                         hctx->ccid3hctx_state);
+        case TFRC_SSTATE_NO_SENT:
+                DCCP_BUG("Illegal %s state NO_SENT, sk=%p", dccp_role(sk), sk);
+                /* fall through */
+        case TFRC_SSTATE_TERM:
                 goto out;
         }
 
@@ -264,7 +263,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk,
         long delay;
         int rc = -ENOTCONN;
 
-        BUG_ON(hctx == NULL || hctx->ccid3hctx_state == TFRC_SSTATE_TERM);
+        BUG_ON(hctx == NULL);
 
         /* Check if pure ACK or Terminating*/
         /*
@@ -282,9 +281,8 @@ static int ccid3_hc_tx_send_packet(struct sock *sk,
 
                 rc = -ENOBUFS;
                 if (unlikely(new_packet == NULL)) {
-                        LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, not enough "
-                                       "mem to add to history, send refused\n",
-                                       __FUNCTION__, dccp_role(sk), sk);
+                        DCCP_WARN("%s, sk=%p, not enough mem to add to history,"
+                                  "send refused\n", dccp_role(sk), sk);
                         goto out;
                 }
 
@@ -317,9 +315,8 @@ static int ccid3_hc_tx_send_packet(struct sock *sk,
                 /* divide by -1000 is to convert to ms and get sign right */
                 rc = delay > 0 ? delay : 0;
                 break;
-        default:
-                DCCP_BUG("%s, sk=%p, Illegal state (%d)!", dccp_role(sk), sk,
-                         hctx->ccid3hctx_state);
+        case TFRC_SSTATE_TERM:
+                DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
                 rc = -EINVAL;
                 break;
         }
@@ -343,7 +340,7 @@ static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, int len)
         struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
         struct timeval now;
 
-        BUG_ON(hctx == NULL || hctx->ccid3hctx_state == TFRC_SSTATE_TERM);
+        BUG_ON(hctx == NULL);
 
         dccp_timestamp(sk, &now);
 
@@ -354,13 +351,11 @@ static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, int len)
 
                 packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
                 if (unlikely(packet == NULL)) {
-                        LIMIT_NETDEBUG(KERN_WARNING "%s: packet doesn't "
-                                       "exists in history!\n", __FUNCTION__);
+                        DCCP_WARN("packet doesn't exist in history!\n");
                         return;
                 }
                 if (unlikely(packet->dccphtx_sent)) {
-                        LIMIT_NETDEBUG(KERN_WARNING "%s: no unsent packet in "
-                                       "history!\n", __FUNCTION__);
+                        DCCP_WARN("no unsent packet in history!\n");
                         return;
                 }
                 packet->dccphtx_tstamp = now;
@@ -395,9 +390,8 @@ static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, int len)
         case TFRC_SSTATE_NO_SENT:
                 /* if first wasn't pure ack */
                 if (len != 0)
-                        printk(KERN_CRIT "%s: %s, First packet sent is noted "
-                                         "as a data packet\n",
-                               __FUNCTION__, dccp_role(sk));
+                        DCCP_CRIT("%s, First packet sent is noted "
+                                  "as a data packet",  dccp_role(sk));
                 return;
         case TFRC_SSTATE_NO_FBACK:
         case TFRC_SSTATE_FBACK:
@@ -410,9 +404,8 @@ static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, int len)
                                           hctx->ccid3hctx_t_ipi);
                 }
                 break;
-        default:
-                DCCP_BUG("%s, sk=%p, Illegal state (%d)!", dccp_role(sk), sk,
-                         hctx->ccid3hctx_state);
+        case TFRC_SSTATE_TERM:
+                DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
                 break;
         }
 }
@@ -430,7 +423,7 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
         u32 x_recv;
         u32 r_sample;
 
-        BUG_ON(hctx == NULL || hctx->ccid3hctx_state == TFRC_SSTATE_TERM);
+        BUG_ON(hctx == NULL);
 
         /* we are only interested in ACKs */
         if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
@@ -455,11 +448,10 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
                 packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
                                                  DCCP_SKB_CB(skb)->dccpd_ack_seq);
                 if (unlikely(packet == NULL)) {
-                        LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, seqno "
-                                       "%llu(%s) does't exist in history!\n",
-                                       __FUNCTION__, dccp_role(sk), sk,
+                        DCCP_WARN("%s, sk=%p, seqno %llu(%s) does't exist "
+                                  "in history!\n",  dccp_role(sk), sk,
                             (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
-                                dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
+                                  dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
                         return;
                 }
 
@@ -467,9 +459,8 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
                 dccp_timestamp(sk, &now);
                 r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
                 if (unlikely(r_sample <= t_elapsed))
-                        LIMIT_NETDEBUG(KERN_WARNING "%s: r_sample=%uus, "
-                                       "t_elapsed=%uus\n",
-                                       __FUNCTION__, r_sample, t_elapsed);
+                        DCCP_WARN("r_sample=%uus,t_elapsed=%uus\n",
+                                  r_sample, t_elapsed);
                 else
                         r_sample -= t_elapsed;
 
@@ -554,9 +545,8 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
                 /* set idle flag */
                 hctx->ccid3hctx_idle = 1;   
                 break;
-        default:
-                DCCP_BUG("%s, sk=%p, Illegal state (%d)!", dccp_role(sk), sk,
-                         hctx->ccid3hctx_state);
+        case TFRC_SSTATE_TERM:
+                DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
                 break;
         }
 }
@@ -596,9 +586,9 @@ static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
         switch (option) {
         case TFRC_OPT_LOSS_EVENT_RATE:
                 if (unlikely(len != 4)) {
-                        LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, invalid "
-                                       "len for TFRC_OPT_LOSS_EVENT_RATE\n",
-                                       __FUNCTION__, dccp_role(sk), sk);
+                        DCCP_WARN("%s, sk=%p, invalid len %d "
+                                  "for TFRC_OPT_LOSS_EVENT_RATE\n",
+                                  dccp_role(sk), sk, len);
                         rc = -EINVAL;
                 } else {
                         opt_recv->ccid3or_loss_event_rate = ntohl(*(__be32 *)value);
@@ -617,9 +607,9 @@ static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
                 break;
         case TFRC_OPT_RECEIVE_RATE:
                 if (unlikely(len != 4)) {
-                        LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, invalid "
-                                       "len for TFRC_OPT_RECEIVE_RATE\n",
-                                       __FUNCTION__, dccp_role(sk), sk);
+                        DCCP_WARN("%s, sk=%p, invalid len %d "
+                                  "for TFRC_OPT_RECEIVE_RATE\n",
+                                  dccp_role(sk), sk, len);
                         rc = -EINVAL;
                 } else {
                         opt_recv->ccid3or_receive_rate = ntohl(*(__be32 *)value);
@@ -722,17 +712,15 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk)
                                                    delta);
         }
                 break;
-        default:
-                DCCP_BUG("%s, sk=%p, Illegal state (%d)!", dccp_role(sk), sk,
-                         hcrx->ccid3hcrx_state);
+        case TFRC_RSTATE_TERM:
+                DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
                 return;
         }
 
         packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
         if (unlikely(packet == NULL)) {
-                LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, no data packet "
-                               "in history!\n",
-                               __FUNCTION__, dccp_role(sk), sk);
+                DCCP_WARN("%s, sk=%p, no data packet in history!\n",
+                          dccp_role(sk), sk);
                 return;
         }
 
@@ -820,29 +808,29 @@ static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
         }
 
         if (unlikely(step == 0)) {
-                LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, packet history "
-                               "contains no data packets!\n",
-                               __FUNCTION__, dccp_role(sk), sk);
+                DCCP_WARN("%s, sk=%p, packet history has no data packets!\n",
+                          dccp_role(sk), sk);
                 return ~0;
         }
 
         if (unlikely(interval == 0)) {
-                LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, Could not find a "
-                               "win_count interval > 0. Defaulting to 1\n",
-                               __FUNCTION__, dccp_role(sk), sk);
+                DCCP_WARN("%s, sk=%p, Could not find a win_count interval > 0."
+                          "Defaulting to 1\n", dccp_role(sk), sk);
                 interval = 1;
         }
 found:
         if (!tail) {
-                LIMIT_NETDEBUG(KERN_WARNING "%s: tail is null\n",
-                   __FUNCTION__);
+                DCCP_CRIT("tail is null\n");
                 return ~0;
         }
         rtt = timeval_delta(&tstamp, &tail->dccphrx_tstamp) * 4 / interval;
         ccid3_pr_debug("%s, sk=%p, approximated RTT to %uus\n",
                        dccp_role(sk), sk, rtt);
-        if (rtt == 0)
-                rtt = 1;
+
+        if (rtt == 0) {
+                DCCP_WARN("RTT==0, setting to 1\n");
+                rtt = 1;
+        }
 
         dccp_timestamp(sk, &tstamp);
         delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
@@ -856,9 +844,7 @@ found:
         tmp2 = (u32)tmp1;
 
         if (!tmp2) {
-                LIMIT_NETDEBUG(KERN_WARNING "tmp2 = 0 "
-                   "%s: x_recv = %u, rtt =%u\n",
-                   __FUNCTION__, x_recv, rtt);
+                DCCP_CRIT("tmp2 = 0, x_recv = %u, rtt =%u\n", x_recv, rtt);
                 return ~0;
         }
 
@@ -904,8 +890,7 @@ static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
                 entry = dccp_li_hist_entry_new(ccid3_li_hist, SLAB_ATOMIC);
 
                 if (entry == NULL) {
-                        printk(KERN_CRIT "%s: out of memory\n",__FUNCTION__);
-                        dump_stack();
+                        DCCP_BUG("out of memory - can not allocate entry");
                         return;
                 }
 
@@ -984,9 +969,7 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
         u32 p_prev, rtt_prev, r_sample, t_elapsed;
         int loss;
 
-        BUG_ON(hcrx == NULL ||
-               !(hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA ||
-                 hcrx->ccid3hcrx_state == TFRC_RSTATE_DATA));
+        BUG_ON(hcrx == NULL);
 
         opt_recv = &dccp_sk(sk)->dccps_options_received;
 
@@ -1004,9 +987,8 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
                 t_elapsed = opt_recv->dccpor_elapsed_time * 10;
 
                 if (unlikely(r_sample <= t_elapsed))
-                        LIMIT_NETDEBUG(KERN_WARNING "%s: r_sample=%uus, "
-                                       "t_elapsed=%uus\n",
-                                       __FUNCTION__, r_sample, t_elapsed);
+                        DCCP_WARN("r_sample=%uus, t_elapsed=%uus\n",
+                                  r_sample, t_elapsed);
                 else
                         r_sample -= t_elapsed;
 
@@ -1030,9 +1012,8 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
         packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp,
                                         skb, SLAB_ATOMIC);
         if (unlikely(packet == NULL)) {
-                LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, Not enough mem to "
-                                "add rx packet to history, consider it lost!\n",
-                               __FUNCTION__, dccp_role(sk), sk);
+                DCCP_WARN("%s, sk=%p, Not enough mem to add rx packet "
+                          "to history, consider it lost!\n", dccp_role(sk), sk);
                 return;
         }
 
@@ -1065,9 +1046,8 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
                         ccid3_hc_rx_send_feedback(sk);
                 }
                 return;
-        default:
-                DCCP_BUG("%s, sk=%p, Illegal state (%d)!",  dccp_role(sk), sk,
-                         hcrx->ccid3hcrx_state);
+        case TFRC_RSTATE_TERM:
+                DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
                 return;
         }
 
@@ -1084,10 +1064,8 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
                 /* Scaling up by 1000000 as fixed decimal */
                 if (i_mean != 0)
                         hcrx->ccid3hcrx_p = 1000000 / i_mean;
-        } else {
-                printk(KERN_CRIT "%s: empty loss hist\n",__FUNCTION__);
-                dump_stack();
-        }
+        } else
+                DCCP_BUG("empty loss history");
 
         if (hcrx->ccid3hcrx_p > p_prev) {
                 ccid3_hc_rx_send_feedback(sk);
diff --git a/net/dccp/ccids/lib/loss_interval.c b/net/dccp/ccids/lib/loss_interval.c
index 906c81ab9d4f..48b9b93f8acb 100644
--- a/net/dccp/ccids/lib/loss_interval.c
+++ b/net/dccp/ccids/lib/loss_interval.c
@@ -13,7 +13,7 @@
 
 #include <linux/module.h>
 #include <net/sock.h>
-
+#include "../../dccp.h"
 #include "loss_interval.h"
 
 struct dccp_li_hist *dccp_li_hist_new(const char *name)
@@ -109,7 +109,7 @@ u32 dccp_li_hist_calc_i_mean(struct list_head *list)
         i_tot = max(i_tot0, i_tot1);
 
         if (!w_tot) {
-                LIMIT_NETDEBUG(KERN_WARNING "%s: w_tot = 0\n", __FUNCTION__);
+                DCCP_WARN("w_tot = 0\n");
                 return 1;
         }
 
@@ -128,7 +128,7 @@ int dccp_li_hist_interval_new(struct dccp_li_hist *hist,
                 entry = dccp_li_hist_entry_new(hist, SLAB_ATOMIC);
                 if (entry == NULL) {
                         dccp_li_hist_purge(hist, list);
-                        dump_stack();
+                        DCCP_BUG("loss interval list entry is NULL");
                         return 0;
                 }
                 entry->dccplih_interval = ~0;
diff --git a/net/dccp/ccids/lib/tfrc_equation.c b/net/dccp/ccids/lib/tfrc_equation.c
index 44076e0c6591..2601012383fb 100644
--- a/net/dccp/ccids/lib/tfrc_equation.c
+++ b/net/dccp/ccids/lib/tfrc_equation.c
@@ -13,9 +13,8 @@
  */
 
 #include <linux/module.h>
-
 #include <asm/div64.h>
-
+#include "../../dccp.h"
 #include "tfrc.h"
 
 #define TFRC_CALC_X_ARRSIZE 500
@@ -588,8 +587,10 @@ u32 tfrc_calc_x(u16 s, u32 R, u32 p)
                 /* p should be 0 unless there is a bug in my code */
                 index = 0;
 
-        if (R == 0)
+        if (R == 0) {
+                DCCP_WARN("RTT==0, setting to 1\n");
                 R = 1; /* RTT can't be zero or else divide by zero */
+        }
 
         BUG_ON(index >= TFRC_CALC_X_ARRSIZE);