[RFC PATCH 12/23] thermal: intel: hfi: Convert table_lock to use flags-handling variants

[Ricardo Neri]

Currently, the table of an HFI instance is only accessed from the HFI
thermal interrupt handler and from the delayed work that sends the thermal
netlink event to user space.

When using Intel Thread Director to support classes of tasks in the
scheduler, the HFI table will also be accessed from the timer interrupt
handler.

As two interrupt handlers will concurrently access the table, update locks
to use raw_spin_[un]lock_irq[save|restore].

Cc: Ben Segall <bsegall@xxxxxxxxxx>
Cc: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Cc: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Cc: Len Brown <len.brown@xxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Tim C. Chen <tim.c.chen@xxxxxxxxx>
Cc: Valentin Schneider <vschneid@xxxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
---
 drivers/thermal/intel/intel_hfi.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/thermal/intel/intel_hfi.c b/drivers/thermal/intel/intel_hfi.c
index 405495dad0b2..4bafe6848d5d 100644
--- a/drivers/thermal/intel/intel_hfi.c
+++ b/drivers/thermal/intel/intel_hfi.c
@@ -175,9 +175,10 @@ static struct workqueue_struct *hfi_updates_wq;
 static void get_hfi_caps(struct hfi_instance *hfi_instance,
 			 struct thermal_genl_cpu_caps *cpu_caps)
 {
+	unsigned long flags;
 	int cpu, i = 0;
 
-	raw_spin_lock_irq(&hfi_instance->table_lock);
+	raw_spin_lock_irqsave(&hfi_instance->table_lock, flags);
 	for_each_cpu(cpu, hfi_instance->cpus) {
 		struct hfi_cpu_data *caps;
 		s16 index;
@@ -199,7 +200,7 @@ static void get_hfi_caps(struct hfi_instance *hfi_instance,
 
 		++i;
 	}
-	raw_spin_unlock_irq(&hfi_instance->table_lock);
+	raw_spin_unlock_irqrestore(&hfi_instance->table_lock, flags);
 }
 
 /*
@@ -262,6 +263,7 @@ void intel_hfi_process_event(__u64 pkg_therm_status_msr_val)
 	struct hfi_instance *hfi_instance;
 	int cpu = smp_processor_id();
 	struct hfi_cpu_info *info;
+	unsigned long flags;
 	u64 new_timestamp;
 
 	if (!pkg_therm_status_msr_val)
@@ -298,7 +300,7 @@ void intel_hfi_process_event(__u64 pkg_therm_status_msr_val)
 		return;
 	}
 
-	raw_spin_lock(&hfi_instance->table_lock);
+	raw_spin_lock_irqsave(&hfi_instance->table_lock, flags);
 
 	/*
 	 * Copy the updated table into our local copy. This includes the new
@@ -307,7 +309,7 @@ void intel_hfi_process_event(__u64 pkg_therm_status_msr_val)
 	memcpy(hfi_instance->local_table, hfi_instance->hw_table,
 	       hfi_features.nr_table_pages << PAGE_SHIFT);
 
-	raw_spin_unlock(&hfi_instance->table_lock);
+	raw_spin_unlock_irqrestore(&hfi_instance->table_lock, flags);
 	raw_spin_unlock(&hfi_instance->event_lock);
 
 	/*
-- 
2.25.1