fcoe: Add runtime debug logging with module parameter debug_logging

This patch converts all FC_DBG statements to use new runtime tunable
debug macros. The fcoe.ko module now has a debug_logging module
parameter.

fcoe_debug_logging is an unsigned integer representing a bitmask of all
available logging levels. Currently only two logging levels are
supported-

   bit
LSB 0 = general fcoe logging
    1 = netdevice related logging

This patch also attempts to clean up some debug statement formatting
so it's more readable.
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/fcoe/fcoe.h

@@ -40,6 +40,30 @@
 #define FCOE_MIN_XID		0x0001	/* the min xid supported by fcoe_sw */
 #define FCOE_MAX_XID		0x07ef	/* the max xid supported by fcoe_sw */
 
+unsigned int fcoe_debug_logging;
+module_param_named(debug_logging, fcoe_debug_logging, int, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(debug_logging, "a bit mask of logging levels");
+
+#define FCOE_LOGGING        0x01 /* General logging, not categorized */
+#define FCOE_NETDEV_LOGGING 0x02 /* Netdevice logging */
+
+#define FCOE_CHECK_LOGGING(LEVEL, CMD)					\
+do {                                                            	\
+	if (unlikely(fcoe_debug_logging & LEVEL))			\
+		do {							\
+			CMD;						\
+		} while (0);						\
+} while (0);
+
+#define FCOE_DBG(fmt, args...)						\
+	FCOE_CHECK_LOGGING(FCOE_LOGGING,				\
+			   printk(KERN_INFO "fcoe: " fmt, ##args);)
+
+#define FCOE_NETDEV_DBG(netdev, fmt, args...)			\
+	FCOE_CHECK_LOGGING(FCOE_NETDEV_LOGGING,			\
+			   printk(KERN_INFO "fcoe: %s" fmt,	\
+				  netdev->name, ##args);)
+
 /*
  * this percpu struct for fcoe
  */