genirq: keep affinities set from userspace across free/request_irq()
Impact: preserve user-modified affinities on interrupts
Kumar Galak noticed that commit
18404756765c713a0be4eb1082920c04822ce588 (genirq: Expose default irq
affinity mask (take 3))
overrides an already set affinity setting across a free /
request_irq(). Happens e.g. with ifdown/ifup of a network device.
Change the logic to mark the affinities as set and keep them
intact. This also fixes the unlocked access to irq_desc in
irq_select_affinity() when called from irq_affinity_proc_write()
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/irq.h b/include/linux/irq.h
index d058c57..36b186e 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -63,7 +63,8 @@
#define IRQ_MOVE_PENDING 0x00200000 /* need to re-target IRQ destination */
#define IRQ_NO_BALANCING 0x00400000 /* IRQ is excluded from balancing */
#define IRQ_SPURIOUS_DISABLED 0x00800000 /* IRQ was disabled by the spurious trap */
-#define IRQ_MOVE_PCNTXT 0x01000000 /* IRQ migration from process context */
+#define IRQ_MOVE_PCNTXT 0x01000000 /* IRQ migration from process context */
+#define IRQ_AFFINITY_SET 0x02000000 /* IRQ affinity was set from userspace*/
#ifdef CONFIG_IRQ_PER_CPU
# define CHECK_IRQ_PER_CPU(var) ((var) & IRQ_PER_CPU)
@@ -210,7 +211,6 @@
#ifdef CONFIG_GENERIC_PENDING_IRQ
-void set_pending_irq(unsigned int irq, cpumask_t mask);
void move_native_irq(int irq);
void move_masked_irq(int irq);
@@ -228,10 +228,6 @@
{
}
-static inline void set_pending_irq(unsigned int irq, cpumask_t mask)
-{
-}
-
#endif /* CONFIG_GENERIC_PENDING_IRQ */
#else /* CONFIG_SMP */
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index c9767e6..64c1c72 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -25,6 +25,8 @@
struct irqaction *action) { }
#endif
+extern int irq_select_affinity_usr(unsigned int irq);
+
/*
* Debugging printout:
*/
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index c498a1b..634a2a9 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -82,24 +82,27 @@
int irq_set_affinity(unsigned int irq, cpumask_t cpumask)
{
struct irq_desc *desc = irq_to_desc(irq);
+ unsigned long flags;
if (!desc->chip->set_affinity)
return -EINVAL;
+ spin_lock_irqsave(&desc->lock, flags);
+
#ifdef CONFIG_GENERIC_PENDING_IRQ
if (desc->status & IRQ_MOVE_PCNTXT || desc->status & IRQ_DISABLED) {
- unsigned long flags;
-
- spin_lock_irqsave(&desc->lock, flags);
desc->affinity = cpumask;
desc->chip->set_affinity(irq, cpumask);
- spin_unlock_irqrestore(&desc->lock, flags);
- } else
- set_pending_irq(irq, cpumask);
+ } else {
+ desc->status |= IRQ_MOVE_PENDING;
+ desc->pending_mask = cpumask;
+ }
#else
desc->affinity = cpumask;
desc->chip->set_affinity(irq, cpumask);
#endif
+ desc->status |= IRQ_AFFINITY_SET;
+ spin_unlock_irqrestore(&desc->lock, flags);
return 0;
}
@@ -107,24 +110,59 @@
/*
* Generic version of the affinity autoselector.
*/
-int irq_select_affinity(unsigned int irq)
+int do_irq_select_affinity(unsigned int irq, struct irq_desc *desc)
{
cpumask_t mask;
- struct irq_desc *desc;
if (!irq_can_set_affinity(irq))
return 0;
cpus_and(mask, cpu_online_map, irq_default_affinity);
- desc = irq_to_desc(irq);
+ /*
+ * Preserve an userspace affinity setup, but make sure that
+ * one of the targets is online.
+ */
+ if (desc->status & IRQ_AFFINITY_SET) {
+ if (cpus_intersects(desc->affinity, cpu_online_map))
+ mask = desc->affinity;
+ else
+ desc->status &= ~IRQ_AFFINITY_SET;
+ }
+
desc->affinity = mask;
desc->chip->set_affinity(irq, mask);
return 0;
}
+#else
+static inline int do_irq_select_affinity(unsigned int irq, struct irq_desc *d)
+{
+ return irq_select_affinity(irq);
+}
#endif
+/*
+ * Called when affinity is set via /proc/irq
+ */
+int irq_select_affinity_usr(unsigned int irq)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ unsigned long flags;
+ int ret;
+
+ spin_lock_irqsave(&desc->lock, flags);
+ ret = do_irq_select_affinity(irq, desc);
+ spin_unlock_irqrestore(&desc->lock, flags);
+
+ return ret;
+}
+
+#else
+static inline int do_select_irq_affinity(int irq, struct irq_desc *desc)
+{
+ return 0;
+}
#endif
/**
@@ -446,7 +484,7 @@
desc->depth = 1;
/* Set default affinity mask once everything is setup */
- irq_select_affinity(irq);
+ do_irq_select_affinity(irq, desc);
} else if ((new->flags & IRQF_TRIGGER_MASK)
&& (new->flags & IRQF_TRIGGER_MASK)
diff --git a/kernel/irq/migration.c b/kernel/irq/migration.c
index 90b920d..9db681d 100644
--- a/kernel/irq/migration.c
+++ b/kernel/irq/migration.c
@@ -1,17 +1,6 @@
#include <linux/irq.h>
-void set_pending_irq(unsigned int irq, cpumask_t mask)
-{
- struct irq_desc *desc = irq_to_desc(irq);
- unsigned long flags;
-
- spin_lock_irqsave(&desc->lock, flags);
- desc->status |= IRQ_MOVE_PENDING;
- desc->pending_mask = mask;
- spin_unlock_irqrestore(&desc->lock, flags);
-}
-
void move_masked_irq(int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index 4d161c70..d257e7d 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -62,7 +62,7 @@
if (!cpus_intersects(new_value, cpu_online_map))
/* Special case for empty set - allow the architecture
code to set default SMP affinity. */
- return irq_select_affinity(irq) ? -EINVAL : count;
+ return irq_select_affinity_usr(irq) ? -EINVAL : count;
irq_set_affinity(irq, new_value);