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Subject[PATCH 12/14] xen: events: remove use of nr_irqs as upper bound on number of pirqs
Date
There isn't really much relationship between the two, other than
nr_irqs often being the larger of the two.

Allows us to remove a nr_irqs sized array, the only users of this
array are MSI setup and restore, neither of which are particularly
performance critical.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
---
drivers/xen/events.c | 59 +++++++++++++++++++++----------------------------
1 files changed, 25 insertions(+), 34 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 002283e..b07f5bb 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -107,8 +107,6 @@ struct irq_info
#define PIRQ_NEEDS_EOI (1 << 0)
#define PIRQ_SHAREABLE (1 << 1)

-static int *pirq_to_irq;
-
static int *evtchn_to_irq;

static DEFINE_PER_CPU(unsigned long [NR_EVENT_CHANNELS/BITS_PER_LONG],
@@ -196,8 +194,6 @@ static void xen_irq_info_pirq_init(unsigned irq,
info->u.pirq.gsi = gsi;
info->u.pirq.vector = vector;
info->u.pirq.flags = flags;
-
- pirq_to_irq[pirq] = irq;
}

/*
@@ -247,16 +243,6 @@ static unsigned pirq_from_irq(unsigned irq)
return info->u.pirq.pirq;
}

-static unsigned gsi_from_irq(unsigned irq)
-{
- struct irq_info *info = info_for_irq(irq);
-
- BUG_ON(info == NULL);
- BUG_ON(info->type != IRQT_PIRQ);
-
- return info->u.pirq.gsi;
-}
-
static enum xen_irq_type type_from_irq(unsigned irq)
{
return info_for_irq(irq)->type;
@@ -653,12 +639,6 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,

spin_lock(&irq_mapping_update_lock);

- if (pirq > nr_irqs) {
- printk(KERN_WARNING "xen_map_pirq_gsi: pirq %d > nr_irqs %d!\n",
- pirq, nr_irqs);
- goto out;
- }
-
irq = find_irq_by_gsi(gsi);
if (irq != -1) {
printk(KERN_INFO "xen_map_pirq_gsi: returning irq %d for gsi %u\n",
@@ -758,7 +738,6 @@ int xen_destroy_irq(int irq)
goto out;
}
}
- pirq_to_irq[info->u.pirq.pirq] = -1;

xen_free_irq(irq);

@@ -769,7 +748,24 @@ out:

int xen_irq_from_pirq(unsigned pirq)
{
- return pirq_to_irq[pirq];
+ int irq;
+
+ struct irq_info *info;
+
+ spin_lock(&irq_mapping_update_lock);
+
+ list_for_each_entry(info, &xen_irq_list_head, list) {
+ if (info == NULL || info->type != IRQT_PIRQ)
+ continue;
+ irq = info->irq;
+ if (info->u.pirq.pirq == pirq)
+ goto out;
+ }
+ irq = -1;
+out:
+ spin_lock(&irq_mapping_update_lock);
+
+ return -1;
}

int bind_evtchn_to_irq(unsigned int evtchn)
@@ -1269,15 +1265,18 @@ static void restore_pirqs(void)
{
int pirq, rc, irq, gsi;
struct physdev_map_pirq map_irq;
+ struct irq_info *info;

- for (pirq = 0; pirq < nr_irqs; pirq++) {
- irq = pirq_to_irq[pirq];
- if (irq == -1)
+ list_for_each_entry(info, &xen_irq_list_head, list) {
+ if (info->type != IRQT_PIRQ)
continue;

+ pirq = info->u.pirq.pirq;
+ gsi = info->u.pirq.gsi;
+ irq = info->irq;
+
/* save/restore of PT devices doesn't work, so at this point the
* only devices present are GSI based emulated devices */
- gsi = gsi_from_irq(irq);
if (!gsi)
continue;

@@ -1291,7 +1290,6 @@ static void restore_pirqs(void)
printk(KERN_WARNING "xen map irq failed gsi=%d irq=%d pirq=%d rc=%d\n",
gsi, irq, pirq, rc);
xen_free_irq(irq);
- pirq_to_irq[pirq] = -1;
continue;
}

@@ -1512,13 +1510,6 @@ void __init xen_init_IRQ(void)
{
int i;

- /* We are using nr_irqs as the maximum number of pirq available but
- * that number is actually chosen by Xen and we don't know exactly
- * what it is. Be careful choosing high pirq numbers. */
- pirq_to_irq = kcalloc(nr_irqs, sizeof(*pirq_to_irq), GFP_KERNEL);
- for (i = 0; i < nr_irqs; i++)
- pirq_to_irq[i] = -1;
-
evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
GFP_KERNEL);
for (i = 0; i < NR_EVENT_CHANNELS; i++)
--
1.5.6.5


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