[patch 2.6.13-rc1] assign_irq_vector() should not panic

[Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>]

Hi,

This is the updated version of the patch I've posted at:

http://marc.theaimsgroup.com/?l=linux-ia64&m\x111803534229544&w=2

Tony, could you consider applying this?

Thanks,
Kenji Kaneshige


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
negative value on error instead of panic.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>


---

 linux-2.6.13-rc1-kanesige/arch/ia64/kernel/iosapic.c  |   13 +++++++++----
 linux-2.6.13-rc1-kanesige/arch/ia64/kernel/irq_ia64.c |   13 +------------
 linux-2.6.13-rc1-kanesige/include/asm-ia64/hw_irq.h   |    1 -
 3 files changed, 10 insertions(+), 17 deletions(-)

diff -puN arch/ia64/kernel/iosapic.c~remove-panic-assign_irq_vector-ia64 arch/ia64/kernel/iosapic.c
--- linux-2.6.13-rc1/arch/ia64/kernel/iosapic.c~remove-panic-assign_irq_vector-ia64	2005-06-30 15:26:19.000000000 +0900
+++ linux-2.6.13-rc1-kanesige/arch/ia64/kernel/iosapic.c	2005-06-30 15:27:16.000000000 +0900
@@ -489,8 +489,6 @@ static int iosapic_find_sharable_vector 
 			}
 		}
 	}
-	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_
 		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 -puN arch/ia64/kernel/irq_ia64.c~remove-panic-assign_irq_vector-ia64 arch/ia64/kernel/irq_ia64.c
--- linux-2.6.13-rc1/arch/ia64/kernel/irq_ia64.c~remove-panic-assign_irq_vector-ia64	2005-06-30 15:26:19.000000000 +0900
+++ linux-2.6.13-rc1-kanesige/arch/ia64/kernel/irq_ia64.c	2005-06-30 15:26:19.000000000 +0900
@@ -63,7 +63,7 @@ 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:
@@ -76,17 +76,6 @@ assign_irq_vector_nopanic (int irq)
 	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)
 {
diff -puN include/asm-ia64/hw_irq.h~remove-panic-assign_irq_vector-ia64 include/asm-ia64/hw_irq.h
--- linux-2.6.13-rc1/include/asm-ia64/hw_irq.h~remove-panic-assign_irq_vector-ia64	2005-06-30 15:27:55.000000000 +0900
+++ linux-2.6.13-rc1-kanesige/include/asm-ia64/hw_irq.h	2005-06-30 15:28:15.000000000 +0900
@@ -81,7 +81,6 @@ extern __u8 isa_irq_to_vector_map[16];
 
 extern struct hw_interrupt_type irq_type_ia64_lsapic;	/* CPU-internal interrupt controller */
 
-extern int assign_irq_vector_nopanic (int irq); /* allocate a free vector without panic */
 extern int assign_irq_vector (int irq);	/* allocate a free vector */
 extern void free_irq_vector (int vector);
 extern void ia64_send_ipi (int cpu, int vector, int delivery_mode, int redirect);

_