[RFC PATCH 0/5] irq: Kill irq_reserve_irq

[RFC PATCH 0/5] irq: Kill irq_reserve_irq

[Yinghai Lu]

Hi,

During reviewing ioapic hotplug patchset, Thomas pointed out that
should not extend irq_reserve_irq for that purpose as that is not
actually reserve.

Neet to clean up old irq_reserve_irq before introduce reserve/alloc_reserved
method for ioapic hotplug.

So here patchset that kill irq_reserve_irq that actually set allocated_irqs.

First remove irq_reserve_irqs for x86, and remove irq_reserve_irq
for sh.
Then in set_irq_chip use irq_alloc_desc instead of irq_reserve_irq.
At last will mark bits in allocated_irqs early for init irqs in !SPARSE_IRQ

Thanks

Yinghai

Yinghai Lu (5):
  x86, irq: Remove not needed irq_reserve_irqs calling
  sh: Remove irq_reserve_irq calling
  irq: Use irq_alloc_desc_at instead of irq_reserve_irq
  s390: Mark bits in allocated_irqs in general code
  genirq: Kill irq_reserve_irq/irq_reserve_irqs

 arch/s390/kernel/irq.c         |  6 +++++-
 arch/x86/kernel/apic/io_apic.c |  3 ---
 drivers/sh/intc/core.c         |  5 +----
 include/linux/irq.h            |  7 +------
 kernel/irq/chip.c              | 14 +++++++-------
 kernel/irq/irqdesc.c           | 35 ++++++++++-------------------------
 6 files changed, 24 insertions(+), 46 deletions(-)

-- 
1.8.4.5

[RFC PATCH 1/5] x86, irq: Remove not needed irq_reserve_irqs calling

[Yinghai Lu]

Now x86 only support sparseirq path, for that path, calling path like:
	early_irq_init
		==> arch_probe_nr_irqs : return legacy irq number
		==> alloc_desc for legacy irqs and set bits in allocated_irqs
		==> arch_early_irq_init
			==> irq_reserve_irqs : set bits again

so we can kill one irq_reserve_irqs calling.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 arch/x86/kernel/apic/io_apic.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 6ad4658..398f9c4 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -206,9 +206,6 @@ int __init arch_early_irq_init(void)
 	count = ARRAY_SIZE(irq_cfgx);
 	node = cpu_to_node(0);
 
-	/* Make sure the legacy interrupts are marked in the bitmap */
-	irq_reserve_irqs(0, legacy_pic->nr_legacy_irqs);
-
 	for (i = 0; i < count; i++) {
 		irq_set_chip_data(i, &cfg[i]);
 		zalloc_cpumask_var_node(&cfg[i].domain, GFP_KERNEL, node);
-- 
1.8.4.5

[RFC PATCH 2/5] sh: Remove irq_reserve_irq calling

in sh calling path:
	register_intc_controller
		=> irq_create_identity_mapping/irq_create_strict_mappins
			=>irq_alloc_desc: it will set bits on allocate_irq
		=> intc_register_irq
			=> irq_reserve_irq: set bits again

so we can kill this irq_reserve_irq calling.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Simon Horman <horms@verge.net.au>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: linux-sh@vger.kernel.org
---
 drivers/sh/intc/core.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/sh/intc/core.c b/drivers/sh/intc/core.c
index 8f32a13..05118f92 100644
--- a/drivers/sh/intc/core.c
+++ b/drivers/sh/intc/core.c
@@ -81,11 +81,8 @@ static void __init intc_register_irq(struct intc_desc *desc,
 	unsigned long flags;
 
 	/*
-	 * Register the IRQ position with the global IRQ map, then insert
-	 * it in to the radix tree.
+	 * insert it in to the radix tree.
 	 */
-	irq_reserve_irq(irq);
-
 	raw_spin_lock_irqsave(&intc_big_lock, flags);
 	radix_tree_insert(&d->tree, enum_id, intc_irq_xlate_get(irq));
 	raw_spin_unlock_irqrestore(&intc_big_lock, flags);
-- 
1.8.4.5

[RFC PATCH 2/5] sh: Remove irq_reserve_irq calling

[Yinghai Lu]

in sh calling path:
	register_intc_controller
		==> irq_create_identity_mapping/irq_create_strict_mappins
			==>irq_alloc_desc: it will set bits on allocate_irq
		==> intc_register_irq
			==> irq_reserve_irq: set bits again

so we can kill this irq_reserve_irq calling.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Simon Horman <horms@verge.net.au>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: linux-sh@vger.kernel.org
---
 drivers/sh/intc/core.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/sh/intc/core.c b/drivers/sh/intc/core.c
index 8f32a13..05118f92 100644
--- a/drivers/sh/intc/core.c
+++ b/drivers/sh/intc/core.c
@@ -81,11 +81,8 @@ static void __init intc_register_irq(struct intc_desc *desc,
 	unsigned long flags;
 
 	/*
-	 * Register the IRQ position with the global IRQ map, then insert
-	 * it in to the radix tree.
+	 * insert it in to the radix tree.
 	 */
-	irq_reserve_irq(irq);
-
 	raw_spin_lock_irqsave(&intc_big_lock, flags);
 	radix_tree_insert(&d->tree, enum_id, intc_irq_xlate_get(irq));
 	raw_spin_unlock_irqrestore(&intc_big_lock, flags);
-- 
1.8.4.5

[RFC PATCH 3/5] irq: Use irq_alloc_desc_at instead of irq_reserve_irq

[Yinghai Lu]

irq_reserve_irq actually only set bit allocated_irq, and it is not really
"reserve" and cause confusion.

For !CONFIG_SPARSE_IRQ path, irq_alloc_desc_at() will only set bit
in allocated_irq.

We can use that instead, kill one irq_reserve_irq() calling.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 kernel/irq/chip.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 6397df2..aff7481 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -28,8 +28,13 @@
 int irq_set_chip(unsigned int irq, struct irq_chip *chip)
 {
 	unsigned long flags;
-	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
+	struct irq_desc *desc;
+
+#ifndef CONFIG_SPARSE_IRQ
+	irq_alloc_desc_at(irq, 0);
+#endif
 
+	desc = irq_get_desc_lock(irq, &flags, 0);
 	if (!desc)
 		return -EINVAL;
 
@@ -38,12 +43,7 @@ int irq_set_chip(unsigned int irq, struct irq_chip *chip)
 
 	desc->irq_data.chip = chip;
 	irq_put_desc_unlock(desc, flags);
-	/*
-	 * For !CONFIG_SPARSE_IRQ make the irq show up in
-	 * allocated_irqs. For the CONFIG_SPARSE_IRQ case, it is
-	 * already marked, and this call is harmless.
-	 */
-	irq_reserve_irq(irq);
+
 	return 0;
 }
 EXPORT_SYMBOL(irq_set_chip);
-- 
1.8.4.5

[RFC PATCH 4/5] s390: Mark bits in allocated_irqs in general code

[Yinghai Lu]

Second irq_reserve_irqs calling is from arch s390, and
s390 does not use SPARSE_IRQ yet.

We could set bits for legacy bits early in !SPARSE_IRQ version
early_irq_init() directly instead of calling irq_reserve_irqs later.

Adding weak version arch_proble_early_allocate_nr_irqs() for
!SPARESE_IRQ, and let s390 to have specific version to
pass correct irq number that need to be marked in allocated_irqs.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
---
 arch/s390/kernel/irq.c |  6 +++++-
 include/linux/irq.h    |  1 +
 kernel/irq/irqdesc.c   | 10 ++++++++++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/s390/kernel/irq.c b/arch/s390/kernel/irq.c
index d42b14c..2838928 100644
--- a/arch/s390/kernel/irq.c
+++ b/arch/s390/kernel/irq.c
@@ -90,9 +90,13 @@ static const struct irq_class irqclass_sub_desc[NR_ARCH_IRQS] = {
 	[CPU_RST]    = {.name = "RST", .desc = "[CPU] CPU Restart"},
 };
 
+int arch_probe_early_allocate_nr_irqs(void)
+{
+	return THIN_INTERRUPT;
+}
+
 void __init init_IRQ(void)
 {
-	irq_reserve_irqs(0, THIN_INTERRUPT);
 	init_cio_interrupts();
 	init_airq_interrupts();
 	init_ext_interrupts();
diff --git a/include/linux/irq.h b/include/linux/irq.h
index d278838..7588ee9 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -623,6 +623,7 @@ int __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
 
 void irq_free_descs(unsigned int irq, unsigned int cnt);
 int irq_reserve_irqs(unsigned int from, unsigned int cnt);
+int arch_probe_early_allocate_nr_irqs(void);
 
 static inline void irq_free_desc(unsigned int irq)
 {
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index a7174617..dfb971c 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -248,10 +248,16 @@ struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 	}
 };
 
+int __weak arch_probe_early_allocate_nr_irqs(void)
+{
+	return 0;
+}
+
 int __init early_irq_init(void)
 {
 	int count, i, node = first_online_node;
 	struct irq_desc *desc;
+	int nr = arch_probe_early_allocate_nr_irqs();
 
 	init_irq_default_affinity();
 
@@ -267,6 +273,10 @@ int __init early_irq_init(void)
 		lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 		desc_set_defaults(i, &desc[i], node, NULL);
 	}
+
+	for (i = 0; i < nr; i++)
+		set_bit(i, allocated_irqs);
+
 	return arch_early_irq_init();
 }
 
-- 
1.8.4.5

[RFC PATCH 5/5] genirq: Kill irq_reserve_irq/irq_reserve_irqs

[Yinghai Lu]

No user any more.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 include/linux/irq.h  |  6 ------
 kernel/irq/irqdesc.c | 25 -------------------------
 2 files changed, 31 deletions(-)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 7588ee9..84ce41a 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -622,7 +622,6 @@ int __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
 	irq_alloc_descs(-1, from, cnt, node)
 
 void irq_free_descs(unsigned int irq, unsigned int cnt);
-int irq_reserve_irqs(unsigned int from, unsigned int cnt);
 int arch_probe_early_allocate_nr_irqs(void);
 
 static inline void irq_free_desc(unsigned int irq)
@@ -630,11 +629,6 @@ static inline void irq_free_desc(unsigned int irq)
 	irq_free_descs(irq, 1);
 }
 
-static inline int irq_reserve_irq(unsigned int irq)
-{
-	return irq_reserve_irqs(irq, 1);
-}
-
 #ifndef irq_reg_writel
 # define irq_reg_writel(val, addr)	writel(val, addr)
 #endif
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index dfb971c..49bf891 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -400,31 +400,6 @@ err:
 EXPORT_SYMBOL_GPL(__irq_alloc_descs);
 
 /**
- * irq_reserve_irqs - mark irqs allocated
- * @from:	mark from irq number
- * @cnt:	number of irqs to mark
- *
- * Returns 0 on success or an appropriate error code
- */
-int irq_reserve_irqs(unsigned int from, unsigned int cnt)
-{
-	unsigned int start;
-	int ret = 0;
-
-	if (!cnt || (from + cnt) > nr_irqs)
-		return -EINVAL;
-
-	mutex_lock(&sparse_irq_lock);
-	start = bitmap_find_next_zero_area(allocated_irqs, nr_irqs, from, cnt, 0);
-	if (start == from)
-		bitmap_set(allocated_irqs, start, cnt);
-	else
-		ret = -EEXIST;
-	mutex_unlock(&sparse_irq_lock);
-	return ret;
-}
-
-/**
  * irq_get_next_irq - get next allocated irq number
  * @offset:	where to start the search
  *
-- 
1.8.4.5