[PATCH v2 12/26] x86, irq: Add realloc_irq_and_cfg_at()

Yinghai Lu
2013-02-08T19:29:46Z

For ioapic hotplug support, we need to reserve irq range for hot
added ioapic controller. After that we need to allocate those
pre-reserved one.

Add realloc_irq_and_cfg_at() to really allocate irq_desc and cfg
as pre-reserved only hold bit in allocate_irqs bit maps.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
---
arch/x86/kernel/apic/io_apic.c | 32 +++++++++++++++++++++++++++++++-
include/linux/irq.h | 5 +++++
kernel/irq/irqdesc.c | 26 ++++++++++++++++++++++++++
3 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index d2b4988..72a1351 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -301,6 +301,36 @@ static void free_irq_at(unsigned int at, struct irq_cfg *cfg)
irq_free_desc(at);
}

+static struct irq_cfg *realloc_irq_and_cfg_at(unsigned int at, int node)
+{
+ struct irq_desc *desc = irq_to_desc(at);
+ struct irq_cfg *cfg;
+ int res;
+
+ if (desc) {
+ if (irq_desc_get_irq_data(desc)->node == node)
+ return alloc_irq_and_cfg_at(at, node);
+
+ cfg = irq_desc_get_chip_data(desc);
+ if (cfg) {
+ /* shared irq */
+ if (!list_empty(&cfg->irq_2_pin))
+ return cfg;
+ free_irq_cfg(at, cfg);
+ }
+ }
+
+ res = irq_realloc_desc_at(at, node);
+ if (res >= 0) {
+ cfg = alloc_irq_cfg(at, node);
+ if (cfg) {
+ irq_set_chip_data(at, cfg);
+ return cfg;
+ }
+ }
+
+ return alloc_irq_and_cfg_at(at, node);
+}

struct io_apic {
unsigned int index;
@@ -3355,7 +3385,7 @@ int arch_setup_ht_irq(unsigned int irq, struct pci_dev *dev)
static int
io_apic_setup_irq_pin(unsigned int irq, int node, struct io_apic_irq_attr *attr)
{
- struct irq_cfg *cfg = alloc_irq_and_cfg_at(irq, node);
+ struct irq_cfg *cfg = realloc_irq_and_cfg_at(irq, node);
int ret;

if (!cfg)
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 4e0fcbb..9c6c047 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -602,6 +602,11 @@ void irq_free_descs(unsigned int irq, unsigned int cnt);
int irq_reserve_irqs(unsigned int from, unsigned int cnt);
int __irq_reserve_irqs(int irq, unsigned int from, unsigned int cnt);

+int __irq_realloc_desc(int at, int node, struct module *owner);
+/* use macros to avoid needing export.h for THIS_MODULE */
+#define irq_realloc_desc_at(at, node) \
+ __irq_realloc_desc(at, node, THIS_MODULE)
+
static inline void irq_free_desc(unsigned int irq)
{
irq_free_descs(irq, 1);
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 3b9fb92..b48f65b 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -99,6 +99,11 @@ EXPORT_SYMBOL_GPL(nr_irqs);
static DEFINE_MUTEX(sparse_irq_lock);
static DECLARE_BITMAP(allocated_irqs, IRQ_BITMAP_BITS);

+static bool __irq_is_reserved(int irq)
+{
+ return !!test_bit(irq, allocated_irqs);
+}
+
#ifdef CONFIG_SPARSE_IRQ

static RADIX_TREE(irq_desc_tree, GFP_KERNEL);
@@ -410,6 +415,27 @@ __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
EXPORT_SYMBOL_GPL(__irq_alloc_descs);

/**
+ * irq_realloc_desc - allocate irq descriptor for irq that is already reserved
+ * @irq: Allocate for specific irq number if irq >= 0
+ * @node: Preferred node on which the irq descriptor should be allocated
+ * @owner: Owning module (can be NULL)
+ *
+ * Returns the irq number or error code
+ */
+int __ref
+__irq_realloc_desc(int irq, int node, struct module *owner)
+{
+ if (!__irq_is_reserved(irq))
+ return -EINVAL;
+
+ if (irq_to_desc(irq))
+ free_desc(irq);
+
+ return alloc_descs(irq, 1, node, owner);
+}
+EXPORT_SYMBOL_GPL(__irq_realloc_desc);
+
+/**
* irq_reserve_irqs - mark irqs allocated
* @from: mark from irq number
* @cnt: number of irqs to mark
--
1.7.10.4