net: sctp: rework debugging framework to use pr_debug and friends

We should get rid of all own SCTP debug printk macros and use the ones
that the kernel offers anyway instead. This makes the code more readable
and conform to the kernel code, and offers all the features of dynamic
debbuging that pr_debug() et al has, such as only turning on/off portions
of debug messages at runtime through debugfs. The runtime cost of having
CONFIG_DYNAMIC_DEBUG enabled, but none of the debug statements printing,
is negligible [1]. If kernel debugging is completly turned off, then these
statements will also compile into "empty" functions.

While we're at it, we also need to change the Kconfig option as it /now/
only refers to the ifdef'ed code portions in outqueue.c that enable further
debugging/tracing of SCTP transaction fields. Also, since SCTP_ASSERT code
was enabled with this Kconfig option and has now been removed, we
transform those code parts into WARNs resp. where appropriate BUG_ONs so
that those bugs can be more easily detected as probably not many people
have SCTP debugging permanently turned on.

To turn on all SCTP debugging, the following steps are needed:

 # mount -t debugfs none /sys/kernel/debug
 # echo -n 'module sctp +p' > /sys/kernel/debug/dynamic_debug/control

This can be done more fine-grained on a per file, per line basis and others
as described in [2].

 [1] https://www.kernel.org/doc/ols/2009/ols2009-pages-39-46.pdf
 [2] Documentation/dynamic-debug-howto.txt

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 11 deletions

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index dd71f1f9ba10..362ae6e2fd93 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -741,7 +741,8 @@ struct sctp_chunk *sctp_make_sack(const struct sctp_association *asoc)
 
 	memset(gabs, 0, sizeof(gabs));
 	ctsn = sctp_tsnmap_get_ctsn(map);
-	SCTP_DEBUG_PRINTK("sackCTSNAck sent:  0x%x.\n", ctsn);
+
+	pr_debug("%s: sackCTSNAck sent:0x%x\n", __func__, ctsn);
 
 	/* How much room is needed in the chunk? */
 	num_gabs = sctp_tsnmap_num_gabs(map, gabs);
@@ -1287,10 +1288,8 @@ struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
 
 	if (!retval)
 		goto nodata;
-
-	if (!sk) {
-		SCTP_DEBUG_PRINTK("chunkifying skb %p w/o an sk\n", skb);
-	}
+	if (!sk)
+		pr_debug("%s: chunkifying skb:%p w/o an sk\n", __func__, skb);
 
 	INIT_LIST_HEAD(&retval->list);
 	retval->skb		= skb;
@@ -2191,8 +2190,9 @@ static sctp_ierror_t sctp_verify_param(struct net *net,
 		break;
 fallthrough:
 	default:
-		SCTP_DEBUG_PRINTK("Unrecognized param: %d for chunk %d.\n",
-				ntohs(param.p->type), cid);
+		pr_debug("%s: unrecognized param:%d for chunk:%d\n",
+			 __func__, ntohs(param.p->type), cid);
+
 		retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
 		break;
 	}
@@ -2516,7 +2516,7 @@ do_addr_param:
 		break;
 
 	case SCTP_PARAM_HOST_NAME_ADDRESS:
-		SCTP_DEBUG_PRINTK("unimplemented SCTP_HOST_NAME_ADDRESS\n");
+		pr_debug("%s: unimplemented SCTP_HOST_NAME_ADDRESS\n", __func__);
 		break;
 
 	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
@@ -2662,8 +2662,8 @@ fall_through:
 		 * called prior to this routine.  Simply log the error
 		 * here.
 		 */
-		SCTP_DEBUG_PRINTK("Ignoring param: %d for association %p.\n",
-				  ntohs(param.p->type), asoc);
+		pr_debug("%s: ignoring param:%d for association:%p.\n",
+			 __func__, ntohs(param.p->type), asoc);
 		break;
 	}
 
@@ -2805,7 +2805,10 @@ struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
 			totallen += paramlen;
 			totallen += addr_param_len;
 			del_pickup = 1;
-			SCTP_DEBUG_PRINTK("mkasconf_update_ip: picked same-scope del_pending addr, totallen for all addresses is %d\n", totallen);
+
+			pr_debug("%s: picked same-scope del_pending addr, "
+				 "totallen for all addresses is %d\n",
+				 __func__, totallen);
 		}
 	}