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, 0 insertions, 75 deletions

diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index e6b95bc4d8e6..d8e37ecea691 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -83,16 +83,6 @@
 #include <net/sctp/structs.h>
 #include <net/sctp/constants.h>
 
-
-/* Set SCTP_DEBUG flag via config if not already set. */
-#ifndef SCTP_DEBUG
-#ifdef CONFIG_SCTP_DBG_MSG
-#define SCTP_DEBUG      1
-#else
-#define SCTP_DEBUG      0
-#endif /* CONFIG_SCTP_DBG */
-#endif /* SCTP_DEBUG */
-
 #ifdef CONFIG_IP_SCTP_MODULE
 #define SCTP_PROTOSW_FLAG 0
 #else /* static! */
@@ -270,61 +260,6 @@ static inline void sctp_max_rto(struct sctp_association *asoc,
         }
 }
 
-/* Print debugging messages.  */
-#if SCTP_DEBUG
-extern int sctp_debug_flag;
-#define SCTP_DEBUG_PRINTK(fmt, args...)                 \
-do {                                                    \
-        if (sctp_debug_flag)                            \
-                printk(KERN_DEBUG pr_fmt(fmt), ##args); \
-} while (0)
-#define SCTP_DEBUG_PRINTK_CONT(fmt, args...)            \
-do {                                                    \
-        if (sctp_debug_flag)                            \
-                pr_cont(fmt, ##args);                   \
-} while (0)
-#define SCTP_DEBUG_PRINTK_IPADDR(fmt_lead, fmt_trail,                   \
-                                 args_lead, addr, args_trail...)        \
-do {                                                                    \
-        const union sctp_addr *_addr = (addr);                          \
-        if (sctp_debug_flag) {                                          \
-                if (_addr->sa.sa_family == AF_INET6) {                  \
-                        printk(KERN_DEBUG                               \
-                               pr_fmt(fmt_lead "%pI6" fmt_trail),       \
-                               args_lead,                               \
-                               &_addr->v6.sin6_addr,                    \
-                               args_trail);                             \
-                } else {                                                \
-                        printk(KERN_DEBUG                               \
-                               pr_fmt(fmt_lead "%pI4" fmt_trail),       \
-                               args_lead,                               \
-                               &_addr->v4.sin_addr.s_addr,              \
-                               args_trail);                             \
-                }                                                       \
-        }                                                               \
-} while (0)
-#define SCTP_ENABLE_DEBUG { sctp_debug_flag = 1; }
-#define SCTP_DISABLE_DEBUG { sctp_debug_flag = 0; }
-
-#define SCTP_ASSERT(expr, str, func) \
-        if (!(expr)) { \
-                SCTP_DEBUG_PRINTK("Assertion Failed: %s(%s) at %s:%s:%d\n", \
-                        str, (#expr), __FILE__, __func__, __LINE__); \
-                func; \
-        }
-
-#else   /* SCTP_DEBUG */
-
-#define SCTP_DEBUG_PRINTK(whatever...)
-#define SCTP_DEBUG_PRINTK_CONT(fmt, args...)
-#define SCTP_DEBUG_PRINTK_IPADDR(whatever...)
-#define SCTP_ENABLE_DEBUG
-#define SCTP_DISABLE_DEBUG
-#define SCTP_ASSERT(expr, str, func)
-
-#endif /* SCTP_DEBUG */
-
-
 /*
  * Macros for keeping a global reference of object allocations.
  */
@@ -597,16 +532,6 @@ static inline int param_type2af(__be16 type)
         }
 }
 
-/* Perform some sanity checks. */
-static inline int sctp_sanity_check(void)
-{
-        SCTP_ASSERT(sizeof(struct sctp_ulpevent) <=
-                    sizeof(((struct sk_buff *)0)->cb),
-                    "SCTP: ulpevent does not fit in skb!\n", return 0);
-
-        return 1;
-}
-
 /* Warning: The following hash functions assume a power of two 'size'. */
 /* This is the hash function for the SCTP port hash table. */
 static inline int sctp_phashfn(struct net *net, __u16 lport)