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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 5/9] x86/IRQ: fix locking around vector management
All of __{assign,bind,clear}_irq_vector() manipulate struct irq_desc
fields, and hence ought to be called with the descriptor lock held in
addition to vector_lock. This is currently the case for only
set_desc_affinity() and destroy_irq(), which also clarifies what the
nesting behavior between the locks has to be. Reflect the new
expectation by having these functions all take a descriptor as
parameter instead of an interrupt number.
Drop one of the two leading underscores from all three functions at
the same time.
There's one case left where descriptors get manipulated with just
vector_lock held: setup_vector_irq() assumes its caller to acquire
vector_lock, and hence can't itself acquire the descriptor locks (wrong
lock order). I don't currently see how to address this.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
--- a/xen/arch/x86/irq.c
+++ b/xen/arch/x86/irq.c
@@ -27,6 +27,7 @@
#include <public/physdev.h>
static int parse_irq_vector_map_param(const char *s);
+static void _clear_irq_vector(struct irq_desc *desc);
/* opt_noirqbalance: If true, software IRQ balancing/affinity is disabled. */
bool __read_mostly opt_noirqbalance;
@@ -112,13 +113,12 @@ static void trace_irq_mask(u32 event, in
trace_var(event, 1, sizeof(d), &d);
}
-static int __init __bind_irq_vector(int irq, int vector, const cpumask_t
*cpu_mask)
+static int __init _bind_irq_vector(struct irq_desc *desc, int vector,
+ const cpumask_t *cpu_mask)
{
cpumask_t online_mask;
int cpu;
- struct irq_desc *desc = irq_to_desc(irq);
- BUG_ON((unsigned)irq >= nr_irqs);
BUG_ON((unsigned)vector >= NR_VECTORS);
cpumask_and(&online_mask, cpu_mask, &cpu_online_map);
@@ -129,9 +129,9 @@ static int __init __bind_irq_vector(int
return 0;
if ( desc->arch.vector != IRQ_VECTOR_UNASSIGNED )
return -EBUSY;
- trace_irq_mask(TRC_HW_IRQ_BIND_VECTOR, irq, vector, &online_mask);
+ trace_irq_mask(TRC_HW_IRQ_BIND_VECTOR, desc->irq, vector, &online_mask);
for_each_cpu(cpu, &online_mask)
- per_cpu(vector_irq, cpu)[vector] = irq;
+ per_cpu(vector_irq, cpu)[vector] = desc->irq;
desc->arch.vector = vector;
cpumask_copy(desc->arch.cpu_mask, &online_mask);
if ( desc->arch.used_vectors )
@@ -145,12 +145,18 @@ static int __init __bind_irq_vector(int
int __init bind_irq_vector(int irq, int vector, const cpumask_t *cpu_mask)
{
+ struct irq_desc *desc = irq_to_desc(irq);
unsigned long flags;
int ret;
- spin_lock_irqsave(&vector_lock, flags);
- ret = __bind_irq_vector(irq, vector, cpu_mask);
- spin_unlock_irqrestore(&vector_lock, flags);
+ BUG_ON((unsigned)irq >= nr_irqs);
+
+ spin_lock_irqsave(&desc->lock, flags);
+ spin_lock(&vector_lock);
+ ret = _bind_irq_vector(desc, vector, cpu_mask);
+ spin_unlock(&vector_lock);
+ spin_unlock_irqrestore(&desc->lock, flags);
+
return ret;
}
@@ -235,7 +241,9 @@ void destroy_irq(unsigned int irq)
spin_lock_irqsave(&desc->lock, flags);
desc->handler = &no_irq_type;
- clear_irq_vector(irq);
+ spin_lock(&vector_lock);
+ _clear_irq_vector(desc);
+ spin_unlock(&vector_lock);
desc->arch.used_vectors = NULL;
spin_unlock_irqrestore(&desc->lock, flags);
@@ -256,11 +264,11 @@ static void release_old_vec(struct irq_d
}
}
-static void __clear_irq_vector(int irq)
+static void _clear_irq_vector(struct irq_desc *desc)
{
- int cpu, vector, old_vector;
+ unsigned int cpu;
+ int vector, old_vector, irq = desc->irq;
cpumask_t tmp_mask;
- struct irq_desc *desc = irq_to_desc(irq);
BUG_ON(!desc->arch.vector);
@@ -306,11 +314,14 @@ static void __clear_irq_vector(int irq)
void clear_irq_vector(int irq)
{
+ struct irq_desc *desc = irq_to_desc(irq);
unsigned long flags;
- spin_lock_irqsave(&vector_lock, flags);
- __clear_irq_vector(irq);
- spin_unlock_irqrestore(&vector_lock, flags);
+ spin_lock_irqsave(&desc->lock, flags);
+ spin_lock(&vector_lock);
+ _clear_irq_vector(desc);
+ spin_unlock(&vector_lock);
+ spin_unlock_irqrestore(&desc->lock, flags);
}
int irq_to_vector(int irq)
@@ -445,8 +456,7 @@ static vmask_t *irq_get_used_vector_mask
return ret;
}
-static int __assign_irq_vector(
- int irq, struct irq_desc *desc, const cpumask_t *mask)
+static int _assign_irq_vector(struct irq_desc *desc, const cpumask_t *mask)
{
/*
* NOTE! The local APIC isn't very good at handling
@@ -460,7 +470,8 @@ static int __assign_irq_vector(
* 0x80, because int 0x80 is hm, kind of importantish. ;)
*/
static int current_vector = FIRST_DYNAMIC_VECTOR, current_offset = 0;
- int cpu, err, old_vector;
+ unsigned int cpu;
+ int err, old_vector, irq = desc->irq;
cpumask_t tmp_mask;
vmask_t *irq_used_vectors = NULL;
@@ -570,8 +581,12 @@ int assign_irq_vector(int irq, const cpu
BUG_ON(irq >= nr_irqs || irq <0);
- spin_lock_irqsave(&vector_lock, flags);
- ret = __assign_irq_vector(irq, desc, mask ?: TARGET_CPUS);
+ spin_lock_irqsave(&desc->lock, flags);
+
+ spin_lock(&vector_lock);
+ ret = _assign_irq_vector(desc, mask ?: TARGET_CPUS);
+ spin_unlock(&vector_lock);
+
if ( !ret )
{
ret = desc->arch.vector;
@@ -580,7 +595,8 @@ int assign_irq_vector(int irq, const cpu
else
cpumask_setall(desc->affinity);
}
- spin_unlock_irqrestore(&vector_lock, flags);
+
+ spin_unlock_irqrestore(&desc->lock, flags);
return ret;
}
@@ -754,7 +770,6 @@ void irq_complete_move(struct irq_desc *
unsigned int set_desc_affinity(struct irq_desc *desc, const cpumask_t *mask)
{
- unsigned int irq;
int ret;
unsigned long flags;
cpumask_t dest_mask;
@@ -762,10 +777,8 @@ unsigned int set_desc_affinity(struct ir
if (!cpumask_intersects(mask, &cpu_online_map))
return BAD_APICID;
- irq = desc->irq;
-
spin_lock_irqsave(&vector_lock, flags);
- ret = __assign_irq_vector(irq, desc, mask);
+ ret = _assign_irq_vector(desc, mask);
spin_unlock_irqrestore(&vector_lock, flags);
if (ret < 0)
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