[Bugfix v2 5/5] x86/irq: Trivial cleanups for x86 vector allocation code

[Jiang Liu]

Trivial cleanups for x86 vector allocation code:
1) reorganize apic_chip_data to optimize for size and cache efficiency
2) avoid redundant calling of irq_to_desc()
3) refine code comments

Signed-off-by: Jiang Liu 
---
 arch/x86/kernel/apic/vector.c |   54 ++---
 1 file changed, 23 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index ab54b296a7d0..008114d0d2bd 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -23,9 +23,9 @@
 
 struct apic_chip_data {
struct irq_cfg  cfg;
+   u8  move_in_progress : 1;
cpumask_var_t   domain;
cpumask_var_t   old_domain;
-   u8  move_in_progress : 1;
 };
 
 struct irq_domain *x86_vector_domain;
@@ -38,7 +38,7 @@ static struct apic_chip_data *legacy_irq_data[NR_IRQS_LEGACY];
 
 void lock_vector_lock(void)
 {
-   /* Used to the online set of cpus does not change
+   /* Used to ensure that the online set of cpus does not change
 * during assign_irq_vector.
 */
raw_spin_lock(_lock);
@@ -100,8 +100,7 @@ static void free_apic_chip_data(struct apic_chip_data *data)
}
 }
 
-static int __assign_irq_vector(int irq, struct apic_chip_data *d,
-  const struct cpumask *mask)
+static int assign_irq_vector(struct irq_data *data, const struct cpumask *mask)
 {
/*
 * NOTE! The local APIC isn't very good at handling
@@ -116,11 +115,15 @@ static int __assign_irq_vector(int irq, struct 
apic_chip_data *d,
 */
static int current_vector = FIRST_EXTERNAL_VECTOR + VECTOR_OFFSET_START;
static int current_offset = VECTOR_OFFSET_START % 16;
-   int cpu, err;
+   int cpu, err = -EBUSY;
+   struct irq_desc *desc = irq_data_to_desc(data);
+   struct apic_chip_data *d = data->chip_data;
unsigned int dest;
+   unsigned long flags;
 
+   raw_spin_lock_irqsave(_lock, flags);
if (cpumask_intersects(d->old_domain, cpu_online_mask))
-   return -EBUSY;
+   goto out;
 
/* Only try and allocate irqs on cpus that are present */
err = -ENOSPC;
@@ -186,7 +189,7 @@ next:
d->cfg.vector = vector;
d->cfg.dest_apicid = dest;
for_each_cpu_and(new_cpu, vector_cpumask, cpu_online_mask)
-   per_cpu(vector_irq, new_cpu)[vector] = irq_to_desc(irq);
+   per_cpu(vector_irq, new_cpu)[vector] = desc;
cpumask_copy(d->domain, vector_cpumask);
err = 0;
break;
@@ -196,37 +199,27 @@ next:
cpumask_and(d->old_domain, d->old_domain, cpu_online_mask);
d->move_in_progress = !cpumask_empty(d->old_domain);
}
-
-   return err;
-}
-
-static int assign_irq_vector(int irq, struct apic_chip_data *data,
-const struct cpumask *mask)
-{
-   int err;
-   unsigned long flags;
-
-   raw_spin_lock_irqsave(_lock, flags);
-   err = __assign_irq_vector(irq, data, mask);
+out:
raw_spin_unlock_irqrestore(_lock, flags);
+
return err;
 }
 
-static int assign_irq_vector_policy(int irq, int node,
-   struct apic_chip_data *data,
+static int assign_irq_vector_policy(struct irq_data *data, int node,
struct irq_alloc_info *info)
 {
if (info && info->mask)
-   return assign_irq_vector(irq, data, info->mask);
+   return assign_irq_vector(data, info->mask);
if (node != NUMA_NO_NODE &&
-   assign_irq_vector(irq, data, cpumask_of_node(node)) == 0)
+   assign_irq_vector(data, cpumask_of_node(node)) == 0)
return 0;
-   return assign_irq_vector(irq, data, apic->target_cpus());
+   return assign_irq_vector(data, apic->target_cpus());
 }
 
-static void clear_irq_vector(int irq, struct apic_chip_data *data)
+static void clear_irq_vector(struct irq_data *irq_data)
 {
-   struct irq_desc *desc = irq_to_desc(irq);
+   struct irq_desc *desc = irq_data_to_desc(irq_data);
+   struct apic_chip_data *data = irq_data->chip_data;
int cpu, vector = data->cfg.vector;
 
BUG_ON(!vector);
@@ -274,7 +267,7 @@ static void x86_vector_free_irqs(struct irq_domain *domain,
irq_data = irq_domain_get_irq_data(x86_vector_domain, virq + i);
if (irq_data && irq_data->chip_data) {
raw_spin_lock_irqsave(_lock, flags);
-   clear_irq_vector(virq + i, irq_data->chip_data);
+   clear_irq_vector(irq_data);
free_apic_chip_data(irq_data->chip_data);
irq_domain_reset_irq_data(irq_data);
raw_spin_unlock_irqrestore(_lock, flags);
@@ -319,7 

[Bugfix v2 5/5] x86/irq: Trivial cleanups for x86 vector allocation code

[Jiang Liu]

Trivial cleanups for x86 vector allocation code:
1) reorganize apic_chip_data to optimize for size and cache efficiency
2) avoid redundant calling of irq_to_desc()
3) refine code comments

Signed-off-by: Jiang Liu 
---
 arch/x86/kernel/apic/vector.c |   54 ++---
 1 file changed, 23 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index ab54b296a7d0..008114d0d2bd 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -23,9 +23,9 @@
 
 struct apic_chip_data {
struct irq_cfg  cfg;
+   u8  move_in_progress : 1;
cpumask_var_t   domain;
cpumask_var_t   old_domain;
-   u8  move_in_progress : 1;
 };
 
 struct irq_domain *x86_vector_domain;
@@ -38,7 +38,7 @@ static struct apic_chip_data *legacy_irq_data[NR_IRQS_LEGACY];
 
 void lock_vector_lock(void)
 {
-   /* Used to the online set of cpus does not change
+   /* Used to ensure that the online set of cpus does not change
 * during assign_irq_vector.
 */
raw_spin_lock(_lock);
@@ -100,8 +100,7 @@ static void free_apic_chip_data(struct apic_chip_data *data)
}
 }
 
-static int __assign_irq_vector(int irq, struct apic_chip_data *d,
-  const struct cpumask *mask)
+static int assign_irq_vector(struct irq_data *data, const struct cpumask *mask)
 {
/*
 * NOTE! The local APIC isn't very good at handling
@@ -116,11 +115,15 @@ static int __assign_irq_vector(int irq, struct 
apic_chip_data *d,
 */
static int current_vector = FIRST_EXTERNAL_VECTOR + VECTOR_OFFSET_START;
static int current_offset = VECTOR_OFFSET_START % 16;
-   int cpu, err;
+   int cpu, err = -EBUSY;
+   struct irq_desc *desc = irq_data_to_desc(data);
+   struct apic_chip_data *d = data->chip_data;
unsigned int dest;
+   unsigned long flags;
 
+   raw_spin_lock_irqsave(_lock, flags);
if (cpumask_intersects(d->old_domain, cpu_online_mask))
-   return -EBUSY;
+   goto out;
 
/* Only try and allocate irqs on cpus that are present */
err = -ENOSPC;
@@ -186,7 +189,7 @@ next:
d->cfg.vector = vector;
d->cfg.dest_apicid = dest;
for_each_cpu_and(new_cpu, vector_cpumask, cpu_online_mask)
-   per_cpu(vector_irq, new_cpu)[vector] = irq_to_desc(irq);
+   per_cpu(vector_irq, new_cpu)[vector] = desc;
cpumask_copy(d->domain, vector_cpumask);
err = 0;
break;
@@ -196,37 +199,27 @@ next:
cpumask_and(d->old_domain, d->old_domain, cpu_online_mask);
d->move_in_progress = !cpumask_empty(d->old_domain);
}
-
-   return err;
-}
-
-static int assign_irq_vector(int irq, struct apic_chip_data *data,
-const struct cpumask *mask)
-{
-   int err;
-   unsigned long flags;
-
-   raw_spin_lock_irqsave(_lock, flags);
-   err = __assign_irq_vector(irq, data, mask);
+out:
raw_spin_unlock_irqrestore(_lock, flags);
+
return err;
 }
 
-static int assign_irq_vector_policy(int irq, int node,
-   struct apic_chip_data *data,
+static int assign_irq_vector_policy(struct irq_data *data, int node,
struct irq_alloc_info *info)
 {
if (info && info->mask)
-   return assign_irq_vector(irq, data, info->mask);
+   return assign_irq_vector(data, info->mask);
if (node != NUMA_NO_NODE &&
-   assign_irq_vector(irq, data, cpumask_of_node(node)) == 0)
+   assign_irq_vector(data, cpumask_of_node(node)) == 0)
return 0;
-   return assign_irq_vector(irq, data, apic->target_cpus());
+   return assign_irq_vector(data, apic->target_cpus());
 }
 
-static void clear_irq_vector(int irq, struct apic_chip_data *data)
+static void clear_irq_vector(struct irq_data *irq_data)
 {
-   struct irq_desc *desc = irq_to_desc(irq);
+   struct irq_desc *desc = irq_data_to_desc(irq_data);
+   struct apic_chip_data *data = irq_data->chip_data;
int cpu, vector = data->cfg.vector;
 
BUG_ON(!vector);
@@ -274,7 +267,7 @@ static void x86_vector_free_irqs(struct irq_domain *domain,
irq_data = irq_domain_get_irq_data(x86_vector_domain, virq + i);
if (irq_data && irq_data->chip_data) {
raw_spin_lock_irqsave(_lock, flags);
-   clear_irq_vector(virq + i, irq_data->chip_data);
+   clear_irq_vector(irq_data);
free_apic_chip_data(irq_data->chip_data);
irq_domain_reset_irq_data(irq_data);