diff mbox series

[kernel,v4,2/8] genirq/irqdomain: Clean legacy IRQ allocation

Message ID 20201124061720.86766-3-aik@ozlabs.ru
State Rejected
Headers show
Series genirq/irqdomain: Add reference counting to IRQs | expand

Checks

Context Check Description
snowpatch_ozlabs/needsstable success Patch has no Fixes tags
snowpatch_ozlabs/checkpatch warning total: 0 errors, 1 warnings, 2 checks, 147 lines checked
snowpatch_ozlabs/apply_patch success Successfully applied on branch powerpc/merge (7c94b5d4e9d328a69d43a11d7e3dfd7a6d762cb6)

Commit Message

Alexey Kardashevskiy Nov. 24, 2020, 6:17 a.m. UTC
There are 10 users of __irq_domain_alloc_irqs() and only one - IOAPIC -
passes realloc==true. There is no obvious reason for handling this
specific case in the generic code.

This splits out __irq_domain_alloc_irqs_data() to make it clear what
IOAPIC does and makes __irq_domain_alloc_irqs() cleaner.

This should cause no behavioral change.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 include/linux/irqdomain.h      |  3 ++
 arch/x86/kernel/apic/io_apic.c | 13 +++--
 kernel/irq/irqdomain.c         | 89 ++++++++++++++++++++--------------
 3 files changed, 65 insertions(+), 40 deletions(-)

Comments

Andy Shevchenko Nov. 24, 2020, 9:19 a.m. UTC | #1
On Tue, Nov 24, 2020 at 8:20 AM Alexey Kardashevskiy <aik@ozlabs.ru> wrote:
>
> There are 10 users of __irq_domain_alloc_irqs() and only one - IOAPIC -
> passes realloc==true. There is no obvious reason for handling this
> specific case in the generic code.
>
> This splits out __irq_domain_alloc_irqs_data() to make it clear what
> IOAPIC does and makes __irq_domain_alloc_irqs() cleaner.
>
> This should cause no behavioral change.

> +       ret = __irq_domain_alloc_irqs_data(domain, virq, nr_irqs, node, arg, affinity);
> +       if (ret <= 0)
>                 goto out_free_desc;

Was or wasn't 0 considered as error code previously?

>         return virq;

>  out_free_desc:
>         irq_free_descs(virq, nr_irqs);
>         return ret;
Alexey Kardashevskiy Nov. 24, 2020, 10:56 a.m. UTC | #2
On 11/24/20 8:19 PM, Andy Shevchenko wrote:
> On Tue, Nov 24, 2020 at 8:20 AM Alexey Kardashevskiy <aik@ozlabs.ru> wrote:
>>
>> There are 10 users of __irq_domain_alloc_irqs() and only one - IOAPIC -
>> passes realloc==true. There is no obvious reason for handling this
>> specific case in the generic code.
>>
>> This splits out __irq_domain_alloc_irqs_data() to make it clear what
>> IOAPIC does and makes __irq_domain_alloc_irqs() cleaner.
>>
>> This should cause no behavioral change.
> 
>> +       ret = __irq_domain_alloc_irqs_data(domain, virq, nr_irqs, node, arg, affinity);
>> +       if (ret <= 0)
>>                  goto out_free_desc;
> 
> Was or wasn't 0 considered as error code previously?

Oh. I need to clean this up, the idea is since this does not allocate 
IRQs, this should return error code and not an irq, I'll make this explicit.

> 
>>          return virq;
> 
>>   out_free_desc:
>>          irq_free_descs(virq, nr_irqs);
>>          return ret;
>
Thomas Gleixner Nov. 30, 2020, 9:41 p.m. UTC | #3
Alexey,

On Tue, Nov 24 2020 at 17:17, Alexey Kardashevskiy wrote:
> There are 10 users of __irq_domain_alloc_irqs() and only one - IOAPIC -
> passes realloc==true. There is no obvious reason for handling this
> specific case in the generic code.

There is also no obvious reason for _NOT_ handling it at the core code.

> This splits out __irq_domain_alloc_irqs_data() to make it clear what
> IOAPIC does and makes __irq_domain_alloc_irqs() cleaner.

That's your interpretation of cleaner.

You need to expose __irq_domain_alloc_irqs_data() for that which is a
core only functionality, so it's not cleaner. It's exposing internals
which are not to be exposed.

The right thing to do is to get rid of the legacy allocation of x86
during early_irq_init() which is possible with the recent restructuring
of the interrupt initialization code in x86. That's a cleanup which will
actually remove code and not expose internals just because.

> This should cause no behavioral change.

Should not cause is a pretty weak statement.

You're missing a nasty detail here. Contrary to the normal irqdomain
rules virq 0 _IS_ valid on x86 for historical reasons and that's not
trivial to change.

Thanks,

        tglx
diff mbox series

Patch

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index 71535e87109f..6cc37bba9951 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -470,6 +470,9 @@  static inline struct irq_domain *irq_domain_add_hierarchy(struct irq_domain *par
 					   ops, host_data);
 }
 
+extern int __irq_domain_alloc_irqs_data(struct irq_domain *domain, int virq,
+					unsigned int nr_irqs, int node, void *arg,
+					const struct irq_affinity_desc *affinity);
 extern int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base,
 				   unsigned int nr_irqs, int node, void *arg,
 				   bool realloc,
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 7b3c7e0d4a09..df9c0ab3a119 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -970,9 +970,14 @@  static int alloc_irq_from_domain(struct irq_domain *domain, int ioapic, u32 gsi,
 		return -1;
 	}
 
-	return __irq_domain_alloc_irqs(domain, irq, 1,
-				       ioapic_alloc_attr_node(info),
-				       info, legacy, NULL);
+	if (irq == -1 || !legacy)
+		return __irq_domain_alloc_irqs(domain, irq, 1,
+					       ioapic_alloc_attr_node(info),
+					       info, false, NULL);
+
+	return __irq_domain_alloc_irqs_data(domain, irq, 1,
+					    ioapic_alloc_attr_node(info),
+					    info, NULL);
 }
 
 /*
@@ -1006,7 +1011,7 @@  static int alloc_isa_irq_from_domain(struct irq_domain *domain,
 			return -ENOMEM;
 	} else {
 		info->flags |= X86_IRQ_ALLOC_LEGACY;
-		irq = __irq_domain_alloc_irqs(domain, irq, 1, node, info, true,
+		irq = __irq_domain_alloc_irqs_data(domain, irq, 1, node, info,
 					      NULL);
 		if (irq >= 0) {
 			irq_data = irq_domain_get_irq_data(domain, irq);
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index cf8b374b892d..ca5c78366c85 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -1386,6 +1386,51 @@  int irq_domain_alloc_irqs_hierarchy(struct irq_domain *domain,
 	return domain->ops->alloc(domain, irq_base, nr_irqs, arg);
 }
 
+int __irq_domain_alloc_irqs_data(struct irq_domain *domain, int virq,
+				 unsigned int nr_irqs, int node, void *arg,
+				 const struct irq_affinity_desc *affinity)
+{
+	int i, ret;
+
+	if (domain == NULL) {
+		domain = irq_default_domain;
+		if (WARN(!domain, "domain is NULL; cannot allocate IRQ\n"))
+			return -EINVAL;
+	}
+
+	if (irq_domain_alloc_irq_data(domain, virq, nr_irqs)) {
+		pr_debug("cannot allocate memory for IRQ%d\n", virq);
+		ret = -ENOMEM;
+		goto out_free_irq_data;
+	}
+
+	mutex_lock(&irq_domain_mutex);
+	ret = irq_domain_alloc_irqs_hierarchy(domain, virq, nr_irqs, arg);
+	if (ret < 0) {
+		mutex_unlock(&irq_domain_mutex);
+		goto out_free_irq_data;
+	}
+
+	for (i = 0; i < nr_irqs; i++) {
+		ret = irq_domain_trim_hierarchy(virq + i);
+		if (ret) {
+			mutex_unlock(&irq_domain_mutex);
+			goto out_free_irq_data;
+		}
+	}
+
+	for (i = 0; i < nr_irqs; i++) {
+		irq_domain_insert_irq(virq + i);
+	}
+	mutex_unlock(&irq_domain_mutex);
+
+	return virq;
+
+out_free_irq_data:
+	irq_domain_free_irq_data(virq, nr_irqs);
+	return ret;
+}
+
 /**
  * __irq_domain_alloc_irqs - Allocate IRQs from domain
  * @domain:	domain to allocate from
@@ -1412,7 +1457,7 @@  int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base,
 			    unsigned int nr_irqs, int node, void *arg,
 			    bool realloc, const struct irq_affinity_desc *affinity)
 {
-	int i, ret, virq;
+	int ret, virq;
 
 	if (domain == NULL) {
 		domain = irq_default_domain;
@@ -1420,47 +1465,19 @@  int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base,
 			return -EINVAL;
 	}
 
-	if (realloc && irq_base >= 0) {
-		virq = irq_base;
-	} else {
-		virq = irq_domain_alloc_descs(irq_base, nr_irqs, 0, node,
-					      affinity);
-		if (virq < 0) {
-			pr_debug("cannot allocate IRQ(base %d, count %d)\n",
-				 irq_base, nr_irqs);
-			return virq;
-		}
+	virq = irq_domain_alloc_descs(irq_base, nr_irqs, 0, node, affinity);
+	if (virq < 0) {
+		pr_debug("cannot allocate IRQ(base %d, count %d)\n",
+			 irq_base, nr_irqs);
+		return virq;
 	}
 
-	if (irq_domain_alloc_irq_data(domain, virq, nr_irqs)) {
-		pr_debug("cannot allocate memory for IRQ%d\n", virq);
-		ret = -ENOMEM;
+	ret = __irq_domain_alloc_irqs_data(domain, virq, nr_irqs, node, arg, affinity);
+	if (ret <= 0)
 		goto out_free_desc;
-	}
-
-	mutex_lock(&irq_domain_mutex);
-	ret = irq_domain_alloc_irqs_hierarchy(domain, virq, nr_irqs, arg);
-	if (ret < 0) {
-		mutex_unlock(&irq_domain_mutex);
-		goto out_free_irq_data;
-	}
-
-	for (i = 0; i < nr_irqs; i++) {
-		ret = irq_domain_trim_hierarchy(virq + i);
-		if (ret) {
-			mutex_unlock(&irq_domain_mutex);
-			goto out_free_irq_data;
-		}
-	}
-	
-	for (i = 0; i < nr_irqs; i++)
-		irq_domain_insert_irq(virq + i);
-	mutex_unlock(&irq_domain_mutex);
 
 	return virq;
 
-out_free_irq_data:
-	irq_domain_free_irq_data(virq, nr_irqs);
 out_free_desc:
 	irq_free_descs(virq, nr_irqs);
 	return ret;