Once stop_machine() is gone from the CPU offline path, we won't be able
to depend on disabling preemption to prevent CPUs from going offline
from under us.
Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going
offline, while invoking from atomic context.
Cc: Tony Luck <tony.l...@intel.com>
Cc: Fenghua Yu <fenghua...@intel.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: "Eric W. Biederman" <ebied...@xmission.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: linux-i...@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat <srivatsa.b...@linux.vnet.ibm.com>
---
arch/ia64/kernel/irq_ia64.c | 15 +++++++++++++++
arch/ia64/kernel/perfmon.c | 8 +++++++-
2 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/arch/ia64/kernel/irq_ia64.c b/arch/ia64/kernel/irq_ia64.c
index 1034884..f58b162 100644
--- a/arch/ia64/kernel/irq_ia64.c
+++ b/arch/ia64/kernel/irq_ia64.c
@@ -25,6 +25,7 @@
#include <linux/ptrace.h>
#include <linux/signal.h>
#include <linux/smp.h>
+#include <linux/cpu.h>
#include <linux/threads.h>
#include <linux/bitops.h>
#include <linux/irq.h>
@@ -160,9 +161,11 @@ int bind_irq_vector(int irq, int vector, cpumask_t domain)
unsigned long flags;
int ret;
+ get_online_cpus_atomic();
spin_lock_irqsave(&vector_lock, flags);
ret = __bind_irq_vector(irq, vector, domain);
spin_unlock_irqrestore(&vector_lock, flags);
+ put_online_cpus_atomic();
return ret;
}
@@ -190,9 +193,11 @@ static void clear_irq_vector(int irq)
{
unsigned long flags;
+ get_online_cpus_atomic();
spin_lock_irqsave(&vector_lock, flags);
__clear_irq_vector(irq);
spin_unlock_irqrestore(&vector_lock, flags);
+ put_online_cpus_atomic();
}
int
@@ -204,6 +209,7 @@ ia64_native_assign_irq_vector (int irq)
vector = -ENOSPC;
+ get_online_cpus_atomic();
spin_lock_irqsave(&vector_lock, flags);
for_each_online_cpu(cpu) {
domain = vector_allocation_domain(cpu);
@@ -218,6 +224,7 @@ ia64_native_assign_irq_vector (int irq)
BUG_ON(__bind_irq_vector(irq, vector, domain));
out:
spin_unlock_irqrestore(&vector_lock, flags);
+ put_online_cpus_atomic();
return vector;
}
@@ -302,9 +309,11 @@ int irq_prepare_move(int irq, int cpu)
unsigned long flags;
int ret;
+ get_online_cpus_atomic();
spin_lock_irqsave(&vector_lock, flags);
ret = __irq_prepare_move(irq, cpu);
spin_unlock_irqrestore(&vector_lock, flags);
+ put_online_cpus_atomic();
return ret;
}
@@ -320,11 +329,13 @@ void irq_complete_move(unsigned irq)
if (unlikely(cpu_isset(smp_processor_id(), cfg->old_domain)))
return;
+ get_online_cpus_atomic();
cpumask_and(&cleanup_mask, &cfg->old_domain, cpu_online_mask);
cfg->move_cleanup_count = cpus_weight(cleanup_mask);
for_each_cpu_mask(i, cleanup_mask)
platform_send_ipi(i, IA64_IRQ_MOVE_VECTOR, IA64_IPI_DM_INT, 0);
cfg->move_in_progress = 0;
+ put_online_cpus_atomic();
}
static irqreturn_t smp_irq_move_cleanup_interrupt(int irq, void *dev_id)
@@ -393,10 +404,12 @@ void destroy_and_reserve_irq(unsigned int irq)
dynamic_irq_cleanup(irq);
+ get_online_cpus_atomic();
spin_lock_irqsave(&vector_lock, flags);
__clear_irq_vector(irq);
irq_status[irq] = IRQ_RSVD;
spin_unlock_irqrestore(&vector_lock, flags);
+ put_online_cpus_atomic();
}
/*
@@ -409,6 +422,7 @@ int create_irq(void)
cpumask_t domain = CPU_MASK_NONE;
irq = vector = -ENOSPC;
+ get_online_cpus_atomic();
spin_lock_irqsave(&vector_lock, flags);
for_each_online_cpu(cpu) {
domain = vector_allocation_domain(cpu);
@@ -424,6 +438,7 @@ int create_irq(void)
BUG_ON(__bind_irq_vector(irq, vector, domain));
out:
spin_unlock_irqrestore(&vector_lock, flags);
+ put_online_cpus_atomic();
if (irq >= 0)
dynamic_irq_init(irq);
return irq;
diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index 9ea25fc..16c8303 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -6476,9 +6476,12 @@ pfm_install_alt_pmu_interrupt(pfm_intr_handler_desc_t
*hdl)
/* do the easy test first */
if (pfm_alt_intr_handler) return -EBUSY;
+ get_online_cpus_atomic();
+
/* one at a time in the install or remove, just fail the others */
if (!spin_trylock(&pfm_alt_install_check)) {
- return -EBUSY;
+ ret = -EBUSY;
+ goto out;
}
/* reserve our session */
@@ -6498,6 +6501,7 @@ pfm_install_alt_pmu_interrupt(pfm_intr_handler_desc_t
*hdl)
pfm_alt_intr_handler = hdl;
spin_unlock(&pfm_alt_install_check);
+ put_online_cpus_atomic();
return 0;
@@ -6510,6 +6514,8 @@ cleanup_reserve:
}
spin_unlock(&pfm_alt_install_check);
+out:
+ put_online_cpus_atomic();
return ret;
}
--
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