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Subject[PATCH 18/52] provide __smp_call_function
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This function is used in smp_send_stop(). It's like
smp_call_function_mask, but always go to all online cpus,
and does not take any locks.

It is added to x86_64, but will soon be unified in a common file

Signed-off-by: Glauber Costa <gcosta@redhat.com>
---
arch/x86/kernel/smp_64.c | 34 +++++++++++++++++++++++++++++++++-
1 files changed, 33 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kernel/smp_64.c b/arch/x86/kernel/smp_64.c
index 1d8b863..aa2edb7 100644
--- a/arch/x86/kernel/smp_64.c
+++ b/arch/x86/kernel/smp_64.c
@@ -322,6 +322,38 @@ void unlock_ipi_call_lock(void)
spin_unlock_irq(&call_lock);
}

+static void __smp_call_function(void (*func) (void *info), void *info,
+ int nonatomic, int wait)
+{
+ struct call_data_struct data;
+ int cpus = num_online_cpus() - 1;
+
+ if (!cpus)
+ return;
+
+ data.func = func;
+ data.info = info;
+ atomic_set(&data.started, 0);
+ data.wait = wait;
+ if (wait)
+ atomic_set(&data.finished, 0);
+
+ call_data = &data;
+ mb();
+
+ /* Send a message to all other CPUs and wait for them to respond */
+ send_IPI_allbutself(CALL_FUNCTION_VECTOR);
+
+ /* Wait for response */
+ while (atomic_read(&data.started) != cpus)
+ cpu_relax();
+
+ if (wait)
+ while (atomic_read(&data.finished) != cpus)
+ cpu_relax();
+}
+
+
/*
* this function sends a 'generic call function' IPI to all other CPU
* of the system defined in the mask.
@@ -424,7 +456,7 @@ void smp_send_stop(void)
/* Don't deadlock on the call lock in panic */
nolock = !spin_trylock(&call_lock);
local_irq_save(flags);
- __smp_call_function_mask(cpu_online_map, stop_this_cpu, NULL, 0);
+ __smp_call_function(stop_this_cpu, NULL, 0, 0);
if (!nolock)
spin_unlock(&call_lock);
disable_local_APIC();
--
1.5.0.6


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