[PATCH 05/10] iommu/amd: remove the special case from alloc_irq_table()

From: Sebastian Andrzej Siewior
Date: Thu Mar 22 2018 - 11:25:18 EST


alloc_irq_table() has a special ioapic argument. If set then it will
pre-allocate / reserve the first 32 indexes. The argument is only once
true and it would make alloc_irq_table() a little simpler if we would
extract the special bits to the caller.
The caller of irq_remapping_alloc() is holding irq_domain_mutex so the
initialization of iommu->irte_ops->set_allocated() should not race
against other user.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
drivers/iommu/amd_iommu.c | 34 ++++++++++++++++++++--------------
1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index a87d2fee68db..a5982a61f181 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -3617,7 +3617,7 @@ static struct irq_remap_table *get_irq_table(u16 devid)
return table;
}

-static struct irq_remap_table *alloc_irq_table(u16 devid, bool ioapic)
+static struct irq_remap_table *alloc_irq_table(u16 devid)
{
struct irq_remap_table *table = NULL;
struct amd_iommu *iommu;
@@ -3651,10 +3651,6 @@ static struct irq_remap_table *alloc_irq_table(u16 devid, bool ioapic)
/* Initialize table spin-lock */
raw_spin_lock_init(&table->lock);

- if (ioapic)
- /* Keep the first 32 indexes free for IOAPIC interrupts */
- table->min_index = 32;
-
table->table = kmem_cache_alloc(amd_iommu_irq_cache, GFP_ATOMIC);
if (!table->table) {
kfree(table);
@@ -3669,12 +3665,6 @@ static struct irq_remap_table *alloc_irq_table(u16 devid, bool ioapic)
memset(table->table, 0,
(MAX_IRQS_PER_TABLE * (sizeof(u64) * 2)));

- if (ioapic) {
- int i;
-
- for (i = 0; i < 32; ++i)
- iommu->irte_ops->set_allocated(table, i);
- }

irq_lookup_table[devid] = table;
set_dte_irq_entry(devid, table);
@@ -3704,7 +3694,7 @@ static int alloc_irq_index(u16 devid, int count, bool align)
if (!iommu)
return -ENODEV;

- table = alloc_irq_table(devid, false);
+ table = alloc_irq_table(devid);
if (!table)
return -ENODEV;

@@ -4130,10 +4120,26 @@ static int irq_remapping_alloc(struct irq_domain *domain, unsigned int virq,
return ret;

if (info->type == X86_IRQ_ALLOC_TYPE_IOAPIC) {
- if (alloc_irq_table(devid, true))
+ struct irq_remap_table *table;
+ struct amd_iommu *iommu;
+
+ table = alloc_irq_table(devid);
+ if (table) {
+ if (!table->min_index) {
+ /*
+ * Keep the first 32 indexes free for IOAPIC
+ * interrupts.
+ */
+ table->min_index = 32;
+ iommu = amd_iommu_rlookup_table[devid];
+ for (i = 0; i < 32; ++i)
+ iommu->irte_ops->set_allocated(table, i);
+ }
+ WARN_ON(table->min_index != 32);
index = info->ioapic_pin;
- else
+ } else {
ret = -ENOMEM;
+ }
} else {
bool align = (info->type == X86_IRQ_ALLOC_TYPE_MSI);

--
2.16.2