[PATCH v4 12/28] x86, irq: Convert irq_2_pin list to generic list

[Yinghai Lu <yinghai@kernel.org>]

Now irq_2_pin list is own grown list for ioapic irq/pin tracking.
We can use generic list to replace it so we could use generic helper
functions to operate it.

Also make free_irq_cfg() free irq_2_pin list to support coming ioapic
hotplug.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Joerg Roedel <joro@8bytes.org>
---
 arch/x86/include/asm/hw_irq.h  |  2 +-
 arch/x86/kernel/apic/io_apic.c | 22 ++++++++++++----------
 2 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h
index e4ac559..8504333 100644
--- a/arch/x86/include/asm/hw_irq.h
+++ b/arch/x86/include/asm/hw_irq.h
@@ -139,7 +139,7 @@ struct irq_2_irte {
  * Most irqs are mapped 1:1 with pins.
  */
 struct irq_cfg {
-	struct irq_pin_list	*irq_2_pin;
+	struct list_head	irq_2_pin;
 	cpumask_var_t		domain;
 	cpumask_var_t		old_domain;
 	u8			vector;
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index ccfb1d3..ef2d530 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -66,7 +66,7 @@
 #define __apicdebuginit(type) static type __init
 
 #define for_each_irq_pin(entry, head) \
-	for (entry = head; entry; entry = entry->next)
+	list_for_each_entry(entry, &head, list)
 
 /*
  *      Is the SiS APIC rmw bug present ?
@@ -176,8 +176,8 @@ void mp_save_irq(struct mpc_intsrc *m)
 }
 
 struct irq_pin_list {
+	struct list_head list;
 	int apic, pin;
-	struct irq_pin_list *next;
 };
 
 static struct irq_pin_list *alloc_irq_pin_list(int node)
@@ -213,6 +213,7 @@ int __init arch_early_irq_init(void)
 	irq_reserve_irqs(0, legacy_pic->nr_legacy_irqs);
 
 	for (i = 0; i < count; i++) {
+		INIT_LIST_HEAD(&cfg[i].irq_2_pin);
 		irq_set_chip_data(i, &cfg[i]);
 		zalloc_cpumask_var_node(&cfg[i].domain, GFP_KERNEL, node);
 		zalloc_cpumask_var_node(&cfg[i].old_domain, GFP_KERNEL, node);
@@ -245,6 +246,7 @@ static struct irq_cfg *alloc_irq_cfg(unsigned int irq, int node)
 		goto out_cfg;
 	if (!zalloc_cpumask_var_node(&cfg->old_domain, GFP_KERNEL, node))
 		goto out_domain;
+	INIT_LIST_HEAD(&cfg->irq_2_pin);
 	return cfg;
 out_domain:
 	free_cpumask_var(cfg->domain);
@@ -255,11 +257,15 @@ out_cfg:
 
 static void free_irq_cfg(unsigned int at, struct irq_cfg *cfg)
 {
+	struct irq_pin_list *entry, *tmp;
+
 	if (!cfg)
 		return;
 	irq_set_chip_data(at, NULL);
 	free_cpumask_var(cfg->domain);
 	free_cpumask_var(cfg->old_domain);
+	list_for_each_entry_safe(entry, tmp, &cfg->irq_2_pin, list)
+		kfree(entry);
 	kfree(cfg);
 }
 
@@ -420,15 +426,12 @@ static void ioapic_mask_entry(int apic, int pin)
  */
 static int __add_pin_to_irq_node(struct irq_cfg *cfg, int node, int apic, int pin)
 {
-	struct irq_pin_list **last, *entry;
+	struct irq_pin_list *entry;
 
 	/* don't allow duplicates */
-	last = &cfg->irq_2_pin;
-	for_each_irq_pin(entry, cfg->irq_2_pin) {
+	for_each_irq_pin(entry, cfg->irq_2_pin)
 		if (entry->apic == apic && entry->pin == pin)
 			return 0;
-		last = &entry->next;
-	}
 
 	entry = alloc_irq_pin_list(node);
 	if (!entry) {
@@ -439,7 +442,7 @@ static int __add_pin_to_irq_node(struct irq_cfg *cfg, int node, int apic, int pi
 	entry->apic = apic;
 	entry->pin = pin;
 
-	*last = entry;
+	list_add_tail(&entry->list, &cfg->irq_2_pin);
 	return 0;
 }
 
@@ -1622,8 +1625,7 @@ __apicdebuginit(void) print_IO_APICs(void)
 		cfg = irq_get_chip_data(irq);
 		if (!cfg)
 			continue;
-		entry = cfg->irq_2_pin;
-		if (!entry)
+		if (list_empty(&cfg->irq_2_pin))
 			continue;
 		printk(KERN_DEBUG "IRQ%d ", irq);
 		for_each_irq_pin(entry, cfg->irq_2_pin)
-- 
1.8.1.4