Revert "ACPI, PCI, irq: remove interrupt count restriction"

Revert commit b5bd02695471 (ACPI, PCI, irq: remove interrupt count
restriction) that introduced a boot regression on some systems
where it caused kmalloc() to be used too early.

Link: http://marc.info/?l=linux-acpi&m=145580159209240&w=2
Reported-by: Nalla, Ravikanth <ravikanth.nalla@hpe.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/pci_link.c

@@ -4,7 +4,6 @@
  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
- *  Copyright (c) 2015, The Linux Foundation. All rights reserved.
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  *
@@ -438,6 +437,7 @@ static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
  * enabled system.
  */
 
+#define ACPI_MAX_IRQS		256
 #define ACPI_MAX_ISA_IRQ	16
 
 #define PIRQ_PENALTY_PCI_AVAILABLE	(0)
@@ -447,7 +447,7 @@ static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
 #define PIRQ_PENALTY_ISA_USED		(16*16*16*16*16)
 #define PIRQ_PENALTY_ISA_ALWAYS		(16*16*16*16*16*16)
 
-static int acpi_irq_isa_penalty[ACPI_MAX_ISA_IRQ] = {
+static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ0 timer */
 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ1 keyboard */
 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ2 cascade */
@@ -464,68 +464,9 @@ static int acpi_irq_isa_penalty[ACPI_MAX_ISA_IRQ] = {
 	PIRQ_PENALTY_ISA_USED,		/* IRQ13 fpe, sometimes */
 	PIRQ_PENALTY_ISA_USED,		/* IRQ14 ide0 */
 	PIRQ_PENALTY_ISA_USED,		/* IRQ15 ide1 */
+	/* >IRQ15 */
 };
 
-struct irq_penalty_info {
-	int irq;
-	int penalty;
-	struct list_head node;
-};
-
-static LIST_HEAD(acpi_irq_penalty_list);
-
-static int acpi_irq_get_penalty(int irq)
-{
-	struct irq_penalty_info *irq_info;
-
-	if (irq < ACPI_MAX_ISA_IRQ)
-		return acpi_irq_isa_penalty[irq];
-
-	list_for_each_entry(irq_info, &acpi_irq_penalty_list, node) {
-		if (irq_info->irq == irq)
-			return irq_info->penalty;
-	}
-
-	return 0;
-}
-
-static int acpi_irq_set_penalty(int irq, int new_penalty)
-{
-	struct irq_penalty_info *irq_info;
-
-	/* see if this is a ISA IRQ */
-	if (irq < ACPI_MAX_ISA_IRQ) {
-		acpi_irq_isa_penalty[irq] = new_penalty;
-		return 0;
-	}
-
-	/* next, try to locate from the dynamic list */
-	list_for_each_entry(irq_info, &acpi_irq_penalty_list, node) {
-		if (irq_info->irq == irq) {
-			irq_info->penalty  = new_penalty;
-			return 0;
-		}
-	}
-
-	/* nope, let's allocate a slot for this IRQ */
-	irq_info = kzalloc(sizeof(*irq_info), GFP_KERNEL);
-	if (!irq_info)
-		return -ENOMEM;
-
-	irq_info->irq = irq;
-	irq_info->penalty = new_penalty;
-	list_add_tail(&irq_info->node, &acpi_irq_penalty_list);
-
-	return 0;
-}
-
-static void acpi_irq_add_penalty(int irq, int penalty)
-{
-	int curpen = acpi_irq_get_penalty(irq);
-
-	acpi_irq_set_penalty(irq, curpen + penalty);
-}
-
 int __init acpi_irq_penalty_init(void)
 {
 	struct acpi_pci_link *link;
@@ -546,16 +487,15 @@ int __init acpi_irq_penalty_init(void)
 			    link->irq.possible_count;
 
 			for (i = 0; i < link->irq.possible_count; i++) {
-				if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ) {
-					int irqpos = link->irq.possible[i];
-
-					acpi_irq_add_penalty(irqpos, penalty);
-				}
+				if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ)
+					acpi_irq_penalty[link->irq.
+							 possible[i]] +=
+					    penalty;
 			}
 
 		} else if (link->irq.active) {
-			acpi_irq_add_penalty(link->irq.active,
-					     PIRQ_PENALTY_PCI_POSSIBLE);
+			acpi_irq_penalty[link->irq.active] +=
+			    PIRQ_PENALTY_PCI_POSSIBLE;
 		}
 	}
 
@@ -607,12 +547,12 @@ static int acpi_pci_link_allocate(struct acpi_pci_link *link)
 		 * the use of IRQs 9, 10, 11, and >15.
 		 */
 		for (i = (link->irq.possible_count - 1); i >= 0; i--) {
-			if (acpi_irq_get_penalty(irq) >
-			    acpi_irq_get_penalty(link->irq.possible[i]))
+			if (acpi_irq_penalty[irq] >
+			    acpi_irq_penalty[link->irq.possible[i]])
 				irq = link->irq.possible[i];
 		}
 	}
-	if (acpi_irq_get_penalty(irq) >= PIRQ_PENALTY_ISA_ALWAYS) {
+	if (acpi_irq_penalty[irq] >= PIRQ_PENALTY_ISA_ALWAYS) {
 		printk(KERN_ERR PREFIX "No IRQ available for %s [%s]. "
 			    "Try pci=noacpi or acpi=off\n",
 			    acpi_device_name(link->device),
@@ -628,8 +568,7 @@ static int acpi_pci_link_allocate(struct acpi_pci_link *link)
 			    acpi_device_bid(link->device));
 		return -ENODEV;
 	} else {
-		acpi_irq_add_penalty(link->irq.active, PIRQ_PENALTY_PCI_USING);
-
+		acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
 		printk(KERN_WARNING PREFIX "%s [%s] enabled at IRQ %d\n",
 		       acpi_device_name(link->device),
 		       acpi_device_bid(link->device), link->irq.active);
@@ -839,7 +778,7 @@ static void acpi_pci_link_remove(struct acpi_device *device)
 }
 
 /*
- * modify penalty from cmdline
+ * modify acpi_irq_penalty[] from cmdline
  */
 static int __init acpi_irq_penalty_update(char *str, int used)
 {
@@ -857,10 +796,13 @@ static int __init acpi_irq_penalty_update(char *str, int used)
 		if (irq < 0)
 			continue;
 
+		if (irq >= ARRAY_SIZE(acpi_irq_penalty))
+			continue;
+
 		if (used)
-			acpi_irq_add_penalty(irq, PIRQ_PENALTY_ISA_USED);
+			acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
 		else
-			acpi_irq_set_penalty(irq, PIRQ_PENALTY_PCI_AVAILABLE);
+			acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
 
 		if (retval != 2)	/* no next number */
 			break;
@@ -877,23 +819,18 @@ static int __init acpi_irq_penalty_update(char *str, int used)
  */
 void acpi_penalize_isa_irq(int irq, int active)
 {
-	int penalty;
-
-	if (irq < 0)
-		return;
-
-	if (active)
-		penalty = PIRQ_PENALTY_ISA_USED;
-	else
-		penalty = PIRQ_PENALTY_PCI_USING;
-
-	acpi_irq_add_penalty(irq, penalty);
+	if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) {
+		if (active)
+			acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
+		else
+			acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
+	}
 }
 
 bool acpi_isa_irq_available(int irq)
 {
-	return irq >= 0 &&
-		(acpi_irq_get_penalty(irq) < PIRQ_PENALTY_ISA_ALWAYS);
+	return irq >= 0 && (irq >= ARRAY_SIZE(acpi_irq_penalty) ||
+			    acpi_irq_penalty[irq] < PIRQ_PENALTY_ISA_ALWAYS);
 }
 
 /*
@@ -903,18 +840,13 @@ bool acpi_isa_irq_available(int irq)
  */
 void acpi_penalize_sci_irq(int irq, int trigger, int polarity)
 {
-	int penalty;
-
-	if (irq < 0)
-		return;
-
-	if (trigger != ACPI_MADT_TRIGGER_LEVEL ||
-	    polarity != ACPI_MADT_POLARITY_ACTIVE_LOW)
-		penalty = PIRQ_PENALTY_ISA_ALWAYS;
-	else
-		penalty = PIRQ_PENALTY_PCI_USING;
-
-	acpi_irq_add_penalty(irq, penalty);
+	if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) {
+		if (trigger != ACPI_MADT_TRIGGER_LEVEL ||
+		    polarity != ACPI_MADT_POLARITY_ACTIVE_LOW)
+			acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_ALWAYS;
+		else
+			acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
+	}
 }
 
 /*