[IA64] assign_irq_vector() should not panic

Current assign_irq_vector() will panic if interrupt vectors is running
out. But I think how to handle the case of lack of interrupt vectors
should be handled by the caller of this function. For example, some
PCI devices can raise the interrupt signal via both MSI and I/O
APIC. So even if the driver for these device fails to allocate a
vector for MSI, the driver still has a chance to use I/O APIC based
interrupt. But currently there is no chance for these driver to use
I/O APIC based interrupt because kernel will panic when
assign_irq_vector() fails to allocate interrupt vector.

The following patch changes assign_irq_vector() for ia64 to return
-ENOSPC on error instead of panic (as i386 and x86_64 versions do).

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

2 files changed, 11 insertions, 17 deletions

diff --git a/arch/ia64/kernel/iosapic.c b/arch/ia64/kernel/iosapic.c
index c170be095ccd..7936b62f7a2e 100644
--- a/arch/ia64/kernel/iosapic.c
+++ b/arch/ia64/kernel/iosapic.c
@@ -489,8 +489,6 @@ static int iosapic_find_sharable_vector (unsigned long trigger, unsigned long po
 			}
 		}
 	}
-	if (vector < 0)
-		panic("%s: out of interrupt vectors!\n", __FUNCTION__);
 
 	return vector;
 }
@@ -506,6 +504,8 @@ iosapic_reassign_vector (int vector)
 
 	if (!list_empty(&iosapic_intr_info[vector].rtes)) {
 		new_vector = assign_irq_vector(AUTO_ASSIGN);
+		if (new_vector < 0)
+			panic("%s: out of interrupt vectors!\n", __FUNCTION__);
 		printk(KERN_INFO "Reassigning vector %d to %d\n", vector, new_vector);
 		memcpy(&iosapic_intr_info[new_vector], &iosapic_intr_info[vector],
 		       sizeof(struct iosapic_intr_info));
@@ -734,9 +734,12 @@ again:
 	spin_unlock_irqrestore(&iosapic_lock, flags);
 
 	/* If vector is running out, we try to find a sharable vector */
-	vector = assign_irq_vector_nopanic(AUTO_ASSIGN);
-	if (vector < 0)
+	vector = assign_irq_vector(AUTO_ASSIGN);
+	if (vector < 0) {
 		vector = iosapic_find_sharable_vector(trigger, polarity);
+		if (vector < 0)
+			panic("%s: out of interrupt vectors!\n", __FUNCTION__);
+	}
 
 	spin_lock_irqsave(&irq_descp(vector)->lock, flags);
 	spin_lock(&iosapic_lock);
@@ -884,6 +887,8 @@ iosapic_register_platform_intr (u32 int_type, unsigned int gsi,
 		break;
 	      case ACPI_INTERRUPT_INIT:
 		vector = assign_irq_vector(AUTO_ASSIGN);
+		if (vector < 0)
+			panic("%s: out of interrupt vectors!\n", __FUNCTION__);
 		delivery = IOSAPIC_INIT;
 		break;
 	      case ACPI_INTERRUPT_CPEI:
diff --git a/arch/ia64/kernel/irq_ia64.c b/arch/ia64/kernel/irq_ia64.c
index 4fe60c7a2e90..6c4d59fd0364 100644
--- a/arch/ia64/kernel/irq_ia64.c
+++ b/arch/ia64/kernel/irq_ia64.c
@@ -63,30 +63,19 @@ EXPORT_SYMBOL(isa_irq_to_vector_map);
 static unsigned long ia64_vector_mask[BITS_TO_LONGS(IA64_NUM_DEVICE_VECTORS)];
 
 int
-assign_irq_vector_nopanic (int irq)
+assign_irq_vector (int irq)
 {
 	int pos, vector;
  again:
 	pos = find_first_zero_bit(ia64_vector_mask, IA64_NUM_DEVICE_VECTORS);
 	vector = IA64_FIRST_DEVICE_VECTOR + pos;
 	if (vector > IA64_LAST_DEVICE_VECTOR)
-		return -1;
+		return -ENOSPC;
 	if (test_and_set_bit(pos, ia64_vector_mask))
 		goto again;
 	return vector;
 }
 
-int
-assign_irq_vector (int irq)
-{
-	int vector = assign_irq_vector_nopanic(irq);
-
-	if (vector < 0)
-		panic("assign_irq_vector: out of interrupt vectors!");
-
-	return vector;
-}
-
 void
 free_irq_vector (int vector)
 {