x86: SGI UV: Fix irq affinity for hub based interrupts

This patch fixes handling of uv hub irq affinity.  IRQs with ALL or
NODE affinity can be routed to cpus other than their originally
assigned cpu.  Those with CPU affinity cannot be rerouted.

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
LKML-Reference: <20090930160259.GA7822@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 120 insertions, 8 deletions

diff --git a/arch/x86/kernel/uv_irq.c b/arch/x86/kernel/uv_irq.c
index aeef529917e..9a83775ab0f 100644
--- a/arch/x86/kernel/uv_irq.c
+++ b/arch/x86/kernel/uv_irq.c
@@ -9,10 +9,22 @@
  */
 
 #include <linux/module.h>
+#include <linux/rbtree.h>
 #include <linux/irq.h>
 
 #include <asm/apic.h>
 #include <asm/uv/uv_irq.h>
+#include <asm/uv/uv_hub.h>
+
+/* MMR offset and pnode of hub sourcing interrupts for a given irq */
+struct uv_irq_2_mmr_pnode{
+	struct rb_node list;
+	unsigned long offset;
+	int pnode;
+	int irq;
+};
+static spinlock_t uv_irq_lock;
+static struct rb_root uv_irq_root;
 
 static void uv_noop(unsigned int irq)
 {
@@ -39,25 +51,106 @@ struct irq_chip uv_irq_chip = {
 	.unmask		= uv_noop,
 	.eoi		= uv_ack_apic,
 	.end		= uv_noop,
+	.set_affinity	= uv_set_irq_affinity,
 };
 
 /*
+ * Add offset and pnode information of the hub sourcing interrupts to the
+ * rb tree for a specific irq.
+ */
+static int uv_set_irq_2_mmr_info(int irq, unsigned long offset, unsigned blade)
+{
+	struct rb_node **link = &uv_irq_root.rb_node;
+	struct rb_node *parent = NULL;
+	struct uv_irq_2_mmr_pnode *n;
+	struct uv_irq_2_mmr_pnode *e;
+	unsigned long irqflags;
+
+	n = kmalloc_node(sizeof(struct uv_irq_2_mmr_pnode), GFP_KERNEL,
+				uv_blade_to_memory_nid(blade));
+	if (!n)
+		return -ENOMEM;
+
+	n->irq = irq;
+	n->offset = offset;
+	n->pnode = uv_blade_to_pnode(blade);
+	spin_lock_irqsave(&uv_irq_lock, irqflags);
+	/* Find the right place in the rbtree: */
+	while (*link) {
+		parent = *link;
+		e = rb_entry(parent, struct uv_irq_2_mmr_pnode, list);
+
+		if (unlikely(irq == e->irq)) {
+			/* irq entry exists */
+			e->pnode = uv_blade_to_pnode(blade);
+			e->offset = offset;
+			spin_unlock_irqrestore(&uv_irq_lock, irqflags);
+			kfree(n);
+			return 0;
+		}
+
+		if (irq < e->irq)
+			link = &(*link)->rb_left;
+		else
+			link = &(*link)->rb_right;
+	}
+
+	/* Insert the node into the rbtree. */
+	rb_link_node(&n->list, parent, link);
+	rb_insert_color(&n->list, &uv_irq_root);
+
+	spin_unlock_irqrestore(&uv_irq_lock, irqflags);
+	return 0;
+}
+
+/* Retrieve offset and pnode information from the rb tree for a specific irq */
+int uv_irq_2_mmr_info(int irq, unsigned long *offset, int *pnode)
+{
+	struct uv_irq_2_mmr_pnode *e;
+	struct rb_node *n;
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&uv_irq_lock, irqflags);
+	n = uv_irq_root.rb_node;
+	while (n) {
+		e = rb_entry(n, struct uv_irq_2_mmr_pnode, list);
+
+		if (e->irq == irq) {
+			*offset = e->offset;
+			*pnode = e->pnode;
+			spin_unlock_irqrestore(&uv_irq_lock, irqflags);
+			return 0;
+		}
+
+		if (irq < e->irq)
+			n = n->rb_left;
+		else
+			n = n->rb_right;
+	}
+	spin_unlock_irqrestore(&uv_irq_lock, irqflags);
+	return -1;
+}
+
+/*
  * Set up a mapping of an available irq and vector, and enable the specified
  * MMR that defines the MSI that is to be sent to the specified CPU when an
  * interrupt is raised.
  */
 int uv_setup_irq(char *irq_name, int cpu, int mmr_blade,
-		 unsigned long mmr_offset)
+		 unsigned long mmr_offset, int restrict)
 {
-	int irq;
-	int ret;
+	int irq, ret;
+
+	irq = create_irq_nr(NR_IRQS_LEGACY, uv_blade_to_memory_nid(mmr_blade));
 
-	irq = create_irq();
 	if (irq <= 0)
 		return -EBUSY;
 
-	ret = arch_enable_uv_irq(irq_name, irq, cpu, mmr_blade, mmr_offset);
-	if (ret != irq)
+	ret = arch_enable_uv_irq(irq_name, irq, cpu, mmr_blade, mmr_offset,
+		restrict);
+	if (ret == irq)
+		uv_set_irq_2_mmr_info(irq, mmr_offset, mmr_blade);
+	else
 		destroy_irq(irq);
 
 	return ret;
@@ -71,9 +164,28 @@ EXPORT_SYMBOL_GPL(uv_setup_irq);
  *
  * Set mmr_blade and mmr_offset to what was passed in on uv_setup_irq().
  */
-void uv_teardown_irq(unsigned int irq, int mmr_blade, unsigned long mmr_offset)
+void uv_teardown_irq(unsigned int irq)
 {
-	arch_disable_uv_irq(mmr_blade, mmr_offset);
+	struct uv_irq_2_mmr_pnode *e;
+	struct rb_node *n;
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&uv_irq_lock, irqflags);
+	n = uv_irq_root.rb_node;
+	while (n) {
+		e = rb_entry(n, struct uv_irq_2_mmr_pnode, list);
+		if (e->irq == irq) {
+			arch_disable_uv_irq(e->pnode, e->offset);
+			rb_erase(n, &uv_irq_root);
+			kfree(e);
+			break;
+		}
+		if (irq < e->irq)
+			n = n->rb_left;
+		else
+			n = n->rb_right;
+	}
+	spin_unlock_irqrestore(&uv_irq_lock, irqflags);
 	destroy_irq(irq);
 }
 EXPORT_SYMBOL_GPL(uv_teardown_irq);