lkml.org 
[lkml]   [2006]   [Apr]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] serialize assign_irq_vector() use of static variables
Since assign_irq_vector() can be called at runtime, its access of static
variables should be protected by a lock.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

diff -Npru /home/jbeulich/tmp/linux-2.6.17-rc2/arch/i386/kernel/io_apic.c
2.6.17-rc2-x86-assign_irq_vector-lock/arch/i386/kernel/io_apic.c
--- /home/jbeulich/tmp/linux-2.6.17-rc2/arch/i386/kernel/io_apic.c 2006-04-26 10:55:11.000000000 +0200
+++ 2.6.17-rc2-x86-assign_irq_vector-lock/arch/i386/kernel/io_apic.c 2006-04-25 15:38:32.000000000 +0200
@@ -50,6 +50,7 @@ atomic_t irq_mis_count;
static struct { int pin, apic; } ioapic_i8259 = { -1, -1 };

static DEFINE_SPINLOCK(ioapic_lock);
+static DEFINE_SPINLOCK(vector_lock);

int timer_over_8254 __initdata = 1;

@@ -1152,10 +1153,16 @@ u8 irq_vector[NR_IRQ_VECTORS] __read_mos
int assign_irq_vector(int irq)
{
static int current_vector = FIRST_DEVICE_VECTOR, offset = 0;
+ int vector;
+
+ BUG_ON(irq != AUTO_ASSIGN && (unsigned)irq >= NR_IRQ_VECTORS);
+
+ spin_lock(&vector_lock);

- BUG_ON(irq >= NR_IRQ_VECTORS);
- if (irq != AUTO_ASSIGN && IO_APIC_VECTOR(irq) > 0)
+ if (irq != AUTO_ASSIGN && IO_APIC_VECTOR(irq) > 0) {
+ spin_unlock(&vector_lock);
return IO_APIC_VECTOR(irq);
+ }
next:
current_vector += 8;
if (current_vector == SYSCALL_VECTOR)
@@ -1163,16 +1170,21 @@ next:

if (current_vector >= FIRST_SYSTEM_VECTOR) {
offset++;
- if (!(offset%8))
+ if (!(offset%8)) {
+ spin_unlock(&vector_lock);
return -ENOSPC;
+ }
current_vector = FIRST_DEVICE_VECTOR + offset;
}

- vector_irq[current_vector] = irq;
+ vector = current_vector;
+ vector_irq[vector] = irq;
if (irq != AUTO_ASSIGN)
- IO_APIC_VECTOR(irq) = current_vector;
+ IO_APIC_VECTOR(irq) = vector;
+
+ spin_unlock(&vector_lock);

- return current_vector;
+ return vector;
}

static struct hw_interrupt_type ioapic_level_type;
diff -Npru /home/jbeulich/tmp/linux-2.6.17-rc2/arch/x86_64/kernel/io_apic.c
2.6.17-rc2-x86-assign_irq_vector-lock/arch/x86_64/kernel/io_apic.c
--- /home/jbeulich/tmp/linux-2.6.17-rc2/arch/x86_64/kernel/io_apic.c 2006-04-26 10:55:24.000000000 +0200
+++ 2.6.17-rc2-x86-assign_irq_vector-lock/arch/x86_64/kernel/io_apic.c 2006-04-25 15:38:32.000000000 +0200
@@ -56,6 +56,7 @@ int timer_over_8254 __initdata = 0;
static struct { int pin, apic; } ioapic_i8259 = { -1, -1 };

static DEFINE_SPINLOCK(ioapic_lock);
+static DEFINE_SPINLOCK(vector_lock);

/*
* # of IRQ routing registers
@@ -814,10 +815,16 @@ u8 irq_vector[NR_IRQ_VECTORS] __read_mos
int assign_irq_vector(int irq)
{
static int current_vector = FIRST_DEVICE_VECTOR, offset = 0;
+ int vector;

BUG_ON(irq != AUTO_ASSIGN && (unsigned)irq >= NR_IRQ_VECTORS);
- if (irq != AUTO_ASSIGN && IO_APIC_VECTOR(irq) > 0)
+
+ spin_lock(&vector_lock);
+
+ if (irq != AUTO_ASSIGN && IO_APIC_VECTOR(irq) > 0) {
+ spin_unlock(&vector_lock);
return IO_APIC_VECTOR(irq);
+ }
next:
current_vector += 8;
if (current_vector == IA32_SYSCALL_VECTOR)
@@ -829,11 +836,14 @@ next:
current_vector = FIRST_DEVICE_VECTOR + offset;
}

- vector_irq[current_vector] = irq;
+ vector = current_vector;
+ vector_irq[vector] = irq;
if (irq != AUTO_ASSIGN)
- IO_APIC_VECTOR(irq) = current_vector;
+ IO_APIC_VECTOR(irq) = vector;
+
+ spin_unlock(&vector_lock);

- return current_vector;
+ return vector;
}

extern void (*interrupt[NR_IRQS])(void);

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-04-26 16:09    [W:0.037 / U:3.396 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site