Messages in this thread Patch in this message | | | Date | Wed, 26 Apr 2006 16:07:53 +0200 | From | "Jan Beulich" <> | Subject | [PATCH] serialize assign_irq_vector() use of static variables |
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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);
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