IB/ehca: Allow en/disabling scaling code via module parameter

Allow users to en/disable scaling code when loading ib_ehca module,
rather than requiring the module to be rebuilt to change the setting.
Signed-off-by: Hoang-Nam Nguyen <hnguyen@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/ehca/Kconfig

@@ -7,11 +7,3 @@ config INFINIBAND_EHCA
 	To compile the driver as a module, choose M here. The module
 	will be called ib_ehca.
 
-config INFINIBAND_EHCA_SCALING
-	bool "Scaling support (EXPERIMENTAL)"
-	depends on IBMEBUS && INFINIBAND_EHCA && HOTPLUG_CPU && EXPERIMENTAL
-	default y
-	---help---
-	eHCA scaling support schedules the CQ callbacks to different CPUs.
-
-	To enable this feature choose Y here.

drivers/infiniband/hw/ehca/ehca_classes.h

@@ -277,6 +277,7 @@ extern struct idr ehca_cq_idr;
 extern int ehca_static_rate;
 extern int ehca_port_act_time;
 extern int ehca_use_hp_mr;
+extern int ehca_scaling_code;
 
 struct ipzu_queue_resp {
 	u32 qe_size;      /* queue entry size */

drivers/infiniband/hw/ehca/ehca_irq.c

@@ -63,15 +63,11 @@
 #define ERROR_DATA_LENGTH      EHCA_BMASK_IBM(52,63)
 #define ERROR_DATA_TYPE        EHCA_BMASK_IBM(0,7)
 
-#ifdef CONFIG_INFINIBAND_EHCA_SCALING
-
 static void queue_comp_task(struct ehca_cq *__cq);
 
 static struct ehca_comp_pool* pool;
 static struct notifier_block comp_pool_callback_nb;
 
-#endif
-
 static inline void comp_event_callback(struct ehca_cq *cq)
 {
 	if (!cq->ib_cq.comp_handler)
@@ -423,13 +419,13 @@ static inline void process_eqe(struct ehca_shca *shca, struct ehca_eqe *eqe)
 			return;
 		}
 		reset_eq_pending(cq);
-#ifdef CONFIG_INFINIBAND_EHCA_SCALING
-		queue_comp_task(cq);
-		spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
-#else
-		spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
-		comp_event_callback(cq);
-#endif
+		if (ehca_scaling_code) {
+			queue_comp_task(cq);
+			spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
+		} else {
+			spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
+			comp_event_callback(cq);
+		}
 	} else {
 		ehca_dbg(&shca->ib_device,
 			 "Got non completion event");
@@ -508,13 +504,12 @@ void ehca_process_eq(struct ehca_shca *shca, int is_irq)
 	/* call completion handler for cached eqes */
 	for (i = 0; i < eqe_cnt; i++)
 		if (eq->eqe_cache[i].cq) {
-#ifdef CONFIG_INFINIBAND_EHCA_SCALING
-			spin_lock(&ehca_cq_idr_lock);
-			queue_comp_task(eq->eqe_cache[i].cq);
-			spin_unlock(&ehca_cq_idr_lock);
-#else
-			comp_event_callback(eq->eqe_cache[i].cq);
-#endif
+			if (ehca_scaling_code) {
+				spin_lock(&ehca_cq_idr_lock);
+				queue_comp_task(eq->eqe_cache[i].cq);
+				spin_unlock(&ehca_cq_idr_lock);
+			} else
+				comp_event_callback(eq->eqe_cache[i].cq);
 		} else {
 			ehca_dbg(&shca->ib_device, "Got non completion event");
 			parse_identifier(shca, eq->eqe_cache[i].eqe->entry);
@@ -540,8 +535,6 @@ void ehca_tasklet_eq(unsigned long data)
 	ehca_process_eq((struct ehca_shca*)data, 1);
 }
 
-#ifdef CONFIG_INFINIBAND_EHCA_SCALING
-
 static inline int find_next_online_cpu(struct ehca_comp_pool* pool)
 {
 	int cpu;
@@ -764,14 +757,14 @@ static int comp_pool_callback(struct notifier_block *nfb,
 	return NOTIFY_OK;
 }
 
-#endif
-
 int ehca_create_comp_pool(void)
 {
-#ifdef CONFIG_INFINIBAND_EHCA_SCALING
 	int cpu;
 	struct task_struct *task;
 
+	if (!ehca_scaling_code)
+		return 0;
+
 	pool = kzalloc(sizeof(struct ehca_comp_pool), GFP_KERNEL);
 	if (pool == NULL)
 		return -ENOMEM;
@@ -796,16 +789,19 @@ int ehca_create_comp_pool(void)
 	comp_pool_callback_nb.notifier_call = comp_pool_callback;
 	comp_pool_callback_nb.priority =0;
 	register_cpu_notifier(&comp_pool_callback_nb);
-#endif
+
+	printk(KERN_INFO "eHCA scaling code enabled\n");
 
 	return 0;
 }
 
 void ehca_destroy_comp_pool(void)
 {
-#ifdef CONFIG_INFINIBAND_EHCA_SCALING
 	int i;
 
+	if (!ehca_scaling_code)
+		return;
+
 	unregister_cpu_notifier(&comp_pool_callback_nb);
 
 	for (i = 0; i < NR_CPUS; i++) {
@@ -814,5 +810,4 @@ void ehca_destroy_comp_pool(void)
 	}
 	free_percpu(pool->cpu_comp_tasks);
 	kfree(pool);
-#endif
 }

drivers/infiniband/hw/ehca/ehca_main.c

@@ -62,6 +62,7 @@ int ehca_use_hp_mr     = 0;
 int ehca_port_act_time = 30;
 int ehca_poll_all_eqs  = 1;
 int ehca_static_rate   = -1;
+int ehca_scaling_code  = 1;
 
 module_param_named(open_aqp1,     ehca_open_aqp1,     int, 0);
 module_param_named(debug_level,   ehca_debug_level,   int, 0);
@@ -71,6 +72,7 @@ module_param_named(use_hp_mr,     ehca_use_hp_mr,     int, 0);
 module_param_named(port_act_time, ehca_port_act_time, int, 0);
 module_param_named(poll_all_eqs,  ehca_poll_all_eqs,  int, 0);
 module_param_named(static_rate,   ehca_static_rate,   int, 0);
+module_param_named(scaling_code,   ehca_scaling_code,   int, 0);
 
 MODULE_PARM_DESC(open_aqp1,
 		 "AQP1 on startup (0: no (default), 1: yes)");
@@ -91,6 +93,8 @@ MODULE_PARM_DESC(poll_all_eqs,
 		 " (0: no, 1: yes (default))");
 MODULE_PARM_DESC(static_rate,
 		 "set permanent static rate (default: disabled)");
+MODULE_PARM_DESC(scaling_code,
+		 "set scaling code (0: disabled, 1: enabled/default)");
 
 spinlock_t ehca_qp_idr_lock;
 spinlock_t ehca_cq_idr_lock;