scst_debug: Avoid that compiler warnings depend on the build mode

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>

iscsi-scst/kernel/iscsi.h

@@ -279,9 +279,7 @@ struct iscsi_conn {
 
 	struct list_head rd_list_entry;
 
-#ifdef CONFIG_SCST_EXTRACHECKS
 	struct task_struct *rd_task;
-#endif
 
 	unsigned long last_rcv_time;
 

iscsi-scst/kernel/iscsi_dbg.h

@@ -52,7 +52,7 @@ extern unsigned long iscsi_get_flow_ctrl_or_mgmt_dbg_log_flag(
 	struct iscsi_cmnd *cmnd);
 #else
 #define iscsi_dump_pdu(x) do {} while (0)
-#define iscsi_get_flow_ctrl_or_mgmt_dbg_log_flag(x) do {} while (0)
+#define iscsi_get_flow_ctrl_or_mgmt_dbg_log_flag(x) 0
 #endif
 
 #if defined(CONFIG_SCST_DEBUG) || defined(CONFIG_SCST_TRACING)

scst/include/scst.h

@@ -258,6 +258,16 @@ static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
 #endif
 #endif
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 36) && \
+	(!defined(RHEL_MAJOR) || RHEL_MAJOR -0 < 6)
+/*
+ * See also patch "Add a dummy printk function for the maintenance of unused
+ * printks" (commit 12fdff3fc2483f906ae6404a6e8dcf2550310b6f).
+ */
+static inline __attribute__ ((format (printf, 1, 2)))
+int no_printk(const char *s, ...) { return 0; }
+#endif
+
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 37)
 /*
  * See also patch "sched: Fix softirq time accounting" (commit ID

scst/include/scst_debug.h

@@ -224,9 +224,12 @@ do {									\
 
 #define TRACING_MINOR() (false)
 
-#define TRACE(trace, format, args...) do {} while (0)
-#define PRINT_BUFFER(message, buff, len) do {} while (0)
-#define PRINT_BUFF_FLAG(flag, message, buff, len) do {} while (0)
+#define TRACE(trace, format, args...)			\
+	((void)(trace), no_printk(format, ##args))
+#define PRINT_BUFFER(message, buff, len)		\
+	((void)(message), (void)(buff), (void)(len))
+#define PRINT_BUFF_FLAG(flag, message, buff, len)	\
+	((void)(flag), (void)(message), (void)(buff), (void)(len))
 
 #endif /* CONFIG_SCST_DEBUG || CONFIG_SCST_TRACING */
 
@@ -353,17 +356,20 @@ do {									\
 
 #else  /* CONFIG_SCST_DEBUG */
 
-#define TRACE_MEM(format, args...) do {} while (0)
-#define TRACE_SG(format, args...) do {} while (0)
-#define TRACE_DBG(format, args...) do {} while (0)
-#define TRACE_DBG_FLAG(format, args...) do {} while (0)
-#define TRACE_DBG_SPECIAL(format, args...) do {} while (0)
-#define TRACE_MGMT_DBG(format, args...) do {} while (0)
-#define TRACE_MGMT_DBG_SPECIAL(format, args...) do {} while (0)
+#define TRACE_MEM(format, args...)	no_printk(format, ##args)
+#define TRACE_SG(format, args...)	no_printk(format, ##args)
+#define TRACE_DBG(format, args...)	no_printk(format, ##args)
+#define TRACE_DBG_FLAG(flag, format, args...) \
+	((void)(flag), no_printk(format, ##args))
+#define TRACE_DBG_SPECIAL(format, args...)	no_printk(format, ##args)
+#define TRACE_MGMT_DBG(format, args...)	no_printk(format, ##args)
+#define TRACE_MGMT_DBG_SPECIAL(format, args...)	no_printk(format, ##args)
 #define TRACE_PR(format, args...) do {} while (0)
-#define TRACE_BLOCK(format, args...) do {} while (0)
-#define TRACE_BUFFER(message, buff, len) do {} while (0)
-#define TRACE_BUFF_FLAG(flag, message, buff, len) do {} while (0)
+#define TRACE_BLOCK(format, args...)	no_printk(format, ##args)
+#define TRACE_BUFFER(message, buff, len) \
+	((void)(message), (void)(buff), (void)(len))
+#define TRACE_BUFF_FLAG(flag, message, buff, len) \
+	((void)(flag), (void)(message), (void)(buff), (void)(len))
 
 #ifndef GENERATING_UPSTREAM_PATCH
 #define TRACE_ENTRY() do {} while (0)

scst/src/dev_handlers/scst_vdisk.c

@@ -60,10 +60,9 @@
 #include "scst.h"
 #endif
 
-#if defined(CONFIG_SCST_DEBUG) || defined(CONFIG_SCST_TRACING)
-
 #define TRACE_ORDER	0x80000000
 
+#if defined(CONFIG_SCST_DEBUG) || defined(CONFIG_SCST_TRACING)
 static struct scst_trace_log vdisk_local_trace_tbl[] = {
 	{ TRACE_ORDER,		"order" },
 	{ 0,			NULL }