Currently i915 pmu driver gets registered with linux perf
subsystem with its callback functions implemented, it is
using spin_lock for synchronization where ever is needed.
linux perf subsystem in some instance is using raw_spin_locks
for synchronization and calls the i915 pmu callback functions with
raw_spin_lock held.
The issue is
When PREEMPT_RT is configured in kernel config the normal spin_lock
behaves as mutex lock and when these are called with raw_spin_lock
held race condition can occur.So in the path of the raw_spin_lock
held convert spin_lock into raw_spin_lock where ever is needed.
v2:
- Fix build error below
drivers/gpu/drm/i915/i915_pmu.c:233:31: error: passing argument 1
of ‘_raw_spin_lock_irqsave’ from incompatible pointer type
[-Werror=incompatible-pointer-types]
233 | raw_spin_lock_irqsave(&pmu->lock, flags);
| ^~~~~~~~~~
Signed-off-by: Ravi Kumar Vodapalli <[email protected]>
---
drivers/gpu/drm/i915/i915_pmu.c | 22 +++++++++++-----------
drivers/gpu/drm/i915/i915_pmu.h | 2 +-
2 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index 5bc696bfbb0f..d760ec44a98c 100644
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -230,7 +230,7 @@ static u64 get_rc6(struct intel_gt *gt)
intel_gt_pm_put_async(gt, wakeref);
}
- spin_lock_irqsave(&pmu->lock, flags);
+ raw_spin_lock_irqsave(&pmu->lock, flags);
if (wakeref) {
store_sample(pmu, gt_id, __I915_SAMPLE_RC6, val);
@@ -251,7 +251,7 @@ static u64 get_rc6(struct intel_gt *gt)
else
store_sample(pmu, gt_id, __I915_SAMPLE_RC6_LAST_REPORTED, val);
- spin_unlock_irqrestore(&pmu->lock, flags);
+ raw_spin_unlock_irqrestore(&pmu->lock, flags);
return val;
}
@@ -302,7 +302,7 @@ void i915_pmu_gt_parked(struct intel_gt *gt)
if (!pmu->registered)
return;
- spin_lock_irq(&pmu->lock);
+ raw_spin_lock_irq(&pmu->lock);
park_rc6(gt);
@@ -314,7 +314,7 @@ void i915_pmu_gt_parked(struct intel_gt *gt)
if (pmu->unparked == 0)
pmu->timer_enabled = false;
- spin_unlock_irq(&pmu->lock);
+ raw_spin_unlock_irq(&pmu->lock);
}
void i915_pmu_gt_unparked(struct intel_gt *gt)
@@ -324,7 +324,7 @@ void i915_pmu_gt_unparked(struct intel_gt *gt)
if (!pmu->registered)
return;
- spin_lock_irq(&pmu->lock);
+ raw_spin_lock_irq(&pmu->lock);
/*
* Re-enable sampling timer when GPU goes active.
@@ -334,7 +334,7 @@ void i915_pmu_gt_unparked(struct intel_gt *gt)
pmu->unparked |= BIT(gt->info.id);
- spin_unlock_irq(&pmu->lock);
+ raw_spin_unlock_irq(&pmu->lock);
}
static void
@@ -740,7 +740,7 @@ static void i915_pmu_enable(struct perf_event *event)
if (bit == -1)
goto update;
- spin_lock_irqsave(&pmu->lock, flags);
+ raw_spin_lock_irqsave(&pmu->lock, flags);
/*
* Update the bitmask of enabled events and increment
@@ -782,7 +782,7 @@ static void i915_pmu_enable(struct perf_event *event)
engine->pmu.enable_count[sample]++;
}
- spin_unlock_irqrestore(&pmu->lock, flags);
+ raw_spin_unlock_irqrestore(&pmu->lock, flags);
update:
/*
@@ -803,7 +803,7 @@ static void i915_pmu_disable(struct perf_event *event)
if (bit == -1)
return;
- spin_lock_irqsave(&pmu->lock, flags);
+ raw_spin_lock_irqsave(&pmu->lock, flags);
if (is_engine_event(event)) {
u8 sample = engine_event_sample(event);
@@ -836,7 +836,7 @@ static void i915_pmu_disable(struct perf_event *event)
pmu->timer_enabled &= pmu_needs_timer(pmu);
}
- spin_unlock_irqrestore(&pmu->lock, flags);
+ raw_spin_unlock_irqrestore(&pmu->lock, flags);
}
static void i915_pmu_event_start(struct perf_event *event, int flags)
@@ -1154,7 +1154,7 @@ void i915_pmu_register(struct drm_i915_private *i915)
};
int ret = -ENOMEM;
- spin_lock_init(&pmu->lock);
+ raw_spin_lock_init(&pmu->lock);
hrtimer_setup(&pmu->timer, i915_sample, CLOCK_MONOTONIC,
HRTIMER_MODE_REL);
init_rc6(pmu);
diff --git a/drivers/gpu/drm/i915/i915_pmu.h b/drivers/gpu/drm/i915/i915_pmu.h
index 5826cc81858c..52d4b602310a 100644
--- a/drivers/gpu/drm/i915/i915_pmu.h
+++ b/drivers/gpu/drm/i915/i915_pmu.h
@@ -71,7 +71,7 @@ struct i915_pmu {
/**
* @lock: Lock protecting enable mask and ref count handling.
*/
- spinlock_t lock;
+ raw_spinlock_t lock;
/**
* @unparked: GT unparked mask.
*/
--
2.34.1
