Previously, we assumed we could use mutex_trylock() within an atomic
context, falling back to a working if contended. However, such trickery
is illegal inside interrupt context, and so we need to always use a
worker under such circumstances. As we normally are in process context,
we can typically use a plain mutex, and only defer to a work when we
know we are caller from an interrupt path.
Fixes: 51fbd8de87dc ("drm/i915/pmu: Atomically acquire the gt_pm wakeref")
References: a0855d24fc22d ("locking/mutex: Complain upon mutex API misuse in IRQ contexts")
References: https://bugs.freedesktop.org/show_bug.cgi?id=111626
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_engine_pm.h | 5 +++
drivers/gpu/drm/i915/gt/intel_gt_pm.c | 1 -
drivers/gpu/drm/i915/gt/intel_gt_pm.h | 5 +++
drivers/gpu/drm/i915/gt/intel_lrc.c | 2 +-
drivers/gpu/drm/i915/i915_pmu.c | 6 ++--
drivers/gpu/drm/i915/intel_wakeref.c | 37 +++++++++--------------
drivers/gpu/drm/i915/intel_wakeref.h | 27 +++++++++++------
7 files changed, 46 insertions(+), 37 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.h b/drivers/gpu/drm/i915/gt/intel_engine_pm.h
index 739c50fefcef..6db07bdd1eef 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.h
@@ -31,6 +31,11 @@ static inline void intel_engine_pm_put(struct intel_engine_cs *engine)
intel_wakeref_put(&engine->wakeref);
}
+static inline void intel_engine_pm_put_async(struct intel_engine_cs *engine)
+{
+ intel_wakeref_put_async(&engine->wakeref);
+}
+
void intel_engine_init__pm(struct intel_engine_cs *engine);
#endif /* INTEL_ENGINE_PM_H */
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
index e61f752a3cd5..7a9044ac4b75 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
@@ -105,7 +105,6 @@ static int __gt_park(struct intel_wakeref *wf)
static const struct intel_wakeref_ops wf_ops = {
.get = __gt_unpark,
.put = __gt_park,
- .flags = INTEL_WAKEREF_PUT_ASYNC,
};
void intel_gt_pm_init_early(struct intel_gt *gt)
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.h b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
index b3e17399be9b..990efc27a4e4 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
@@ -32,6 +32,11 @@ static inline void intel_gt_pm_put(struct intel_gt *gt)
intel_wakeref_put(>->wakeref);
}
+static inline void intel_gt_pm_put_async(struct intel_gt *gt)
+{
+ intel_wakeref_put_async(>->wakeref);
+}
+
static inline int intel_gt_pm_wait_for_idle(struct intel_gt *gt)
{
return intel_wakeref_wait_for_idle(>->wakeref);
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 33ce258d484f..b65bc06855b0 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1172,7 +1172,7 @@ __execlists_schedule_out(struct i915_request *rq,
intel_engine_context_out(engine);
execlists_context_status_change(rq, INTEL_CONTEXT_SCHEDULE_OUT);
- intel_gt_pm_put(engine->gt);
+ intel_gt_pm_put_async(engine->gt);
/*
* If this is part of a virtual engine, its next request may
diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index 9b02be0ad4e6..95e824a78d4d 100644
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -190,7 +190,7 @@ static u64 get_rc6(struct intel_gt *gt)
val = 0;
if (intel_gt_pm_get_if_awake(gt)) {
val = __get_rc6(gt);
- intel_gt_pm_put(gt);
+ intel_gt_pm_put_async(gt);
}
spin_lock_irqsave(&pmu->lock, flags);
@@ -360,7 +360,7 @@ engines_sample(struct intel_gt *gt, unsigned int period_ns)
skip:
if (unlikely(mmio_lock))
spin_unlock_irqrestore(mmio_lock, flags);
- intel_engine_pm_put(engine);
+ intel_engine_pm_put_async(engine);
}
}
@@ -398,7 +398,7 @@ frequency_sample(struct intel_gt *gt, unsigned int period_ns)
if (stat)
val = intel_get_cagf(rps, stat);
- intel_gt_pm_put(gt);
+ intel_gt_pm_put_async(gt);
}
add_sample_mult(&pmu->sample[__I915_SAMPLE_FREQ_ACT],
diff --git a/drivers/gpu/drm/i915/intel_wakeref.c b/drivers/gpu/drm/i915/intel_wakeref.c
index 868cc78048d0..8084cded62db 100644
--- a/drivers/gpu/drm/i915/intel_wakeref.c
+++ b/drivers/gpu/drm/i915/intel_wakeref.c
@@ -52,9 +52,20 @@ int __intel_wakeref_get_first(struct intel_wakeref *wf)
return 0;
}
-static void ____intel_wakeref_put_last(struct intel_wakeref *wf)
+void __intel_wakeref_put_last(struct intel_wakeref *wf, unsigned long flags)
{
- if (!atomic_dec_and_test(&wf->count))
+ INTEL_WAKEREF_BUG_ON(work_pending(&wf->work));
+
+ /* Assume we are not in process context and so cannot sleep. */
+ if (flags & INTEL_WAKEREF_PUT_ASYNC) {
+ schedule_work(&wf->work);
+ return;
+ }
+
+ mutex_lock(&wf->mutex);
+
+ INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0);
+ if (unlikely(!atomic_dec_and_test(&wf->count)))
goto unlock;
/* ops->put() must reschedule its own release on error/deferral */
@@ -67,29 +78,9 @@ static void ____intel_wakeref_put_last(struct intel_wakeref *wf)
mutex_unlock(&wf->mutex);
}
-void __intel_wakeref_put_last(struct intel_wakeref *wf)
-{
- INTEL_WAKEREF_BUG_ON(work_pending(&wf->work));
-
- /* Assume we are not in process context and so cannot sleep. */
- if (wf->ops->flags & INTEL_WAKEREF_PUT_ASYNC ||
- !mutex_trylock(&wf->mutex)) {
- schedule_work(&wf->work);
- return;
- }
-
- ____intel_wakeref_put_last(wf);
-}
-
static void __intel_wakeref_put_work(struct work_struct *wrk)
{
- struct intel_wakeref *wf = container_of(wrk, typeof(*wf), work);
-
- if (atomic_add_unless(&wf->count, -1, 1))
- return;
-
- mutex_lock(&wf->mutex);
- ____intel_wakeref_put_last(wf);
+ intel_wakeref_put(container_of(wrk, struct intel_wakeref, work));
}
void __intel_wakeref_init(struct intel_wakeref *wf,
diff --git a/drivers/gpu/drm/i915/intel_wakeref.h b/drivers/gpu/drm/i915/intel_wakeref.h
index 5f0c972a80fb..ff4876093541 100644
--- a/drivers/gpu/drm/i915/intel_wakeref.h
+++ b/drivers/gpu/drm/i915/intel_wakeref.h
@@ -29,9 +29,6 @@ typedef depot_stack_handle_t intel_wakeref_t;
struct intel_wakeref_ops {
int (*get)(struct intel_wakeref *wf);
int (*put)(struct intel_wakeref *wf);
-
- unsigned long flags;
-#define INTEL_WAKEREF_PUT_ASYNC BIT(0)
};
struct intel_wakeref {
@@ -57,7 +54,7 @@ void __intel_wakeref_init(struct intel_wakeref *wf,
} while (0)
int __intel_wakeref_get_first(struct intel_wakeref *wf);
-void __intel_wakeref_put_last(struct intel_wakeref *wf);
+void __intel_wakeref_put_last(struct intel_wakeref *wf, unsigned long flags);
/**
* intel_wakeref_get: Acquire the wakeref
@@ -100,10 +97,9 @@ intel_wakeref_get_if_active(struct intel_wakeref *wf)
}
/**
- * intel_wakeref_put: Release the wakeref
- * @i915: the drm_i915_private device
+ * intel_wakeref_put_flags: Release the wakeref
* @wf: the wakeref
- * @fn: callback for releasing the wakeref, called only on final release.
+ * @flags: control flags
*
* Release our hold on the wakeref. When there are no more users,
* the runtime pm wakeref will be released after the @fn callback is called
@@ -116,11 +112,24 @@ intel_wakeref_get_if_active(struct intel_wakeref *wf)
* code otherwise.
*/
static inline void
-intel_wakeref_put(struct intel_wakeref *wf)
+__intel_wakeref_put(struct intel_wakeref *wf, unsigned long flags)
+#define INTEL_WAKEREF_PUT_ASYNC BIT(0)
{
INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0);
if (unlikely(!atomic_add_unless(&wf->count, -1, 1)))
- __intel_wakeref_put_last(wf);
+ __intel_wakeref_put_last(wf, flags);
+}
+
+static inline void
+intel_wakeref_put(struct intel_wakeref *wf)
+{
+ __intel_wakeref_put(wf, 0);
+}
+
+static inline void
+intel_wakeref_put_async(struct intel_wakeref *wf)
+{
+ __intel_wakeref_put(wf, INTEL_WAKEREF_PUT_ASYNC);
}
/**
--
2.24.0
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