@@ -211,7 +211,8 @@ static inline void intel_context_enter(struct intel_context *ce)
static inline void intel_context_mark_active(struct intel_context *ce)
{
- lockdep_assert_held(&ce->timeline->mutex);
+ lockdep_assert(lockdep_is_held(&ce->timeline->mutex) ||
+ test_bit(CONTEXT_IS_PARKED, &ce->flags));
++ce->active_count;
}
@@ -118,6 +118,7 @@ struct intel_context {
#define CONTEXT_LRCA_DIRTY 9
#define CONTEXT_GUC_INIT 10
#define CONTEXT_PERMA_PIN 11
+#define CONTEXT_IS_PARKED 12
struct {
u64 timeout_us;
@@ -80,39 +80,6 @@ static int __engine_unpark(struct intel_wakeref *wf)
return 0;
}
-#if IS_ENABLED(CONFIG_LOCKDEP)
-
-static unsigned long __timeline_mark_lock(struct intel_context *ce)
-{
- unsigned long flags;
-
- local_irq_save(flags);
- mutex_acquire(&ce->timeline->mutex.dep_map, 2, 0, _THIS_IP_);
-
- return flags;
-}
-
-static void __timeline_mark_unlock(struct intel_context *ce,
- unsigned long flags)
-{
- mutex_release(&ce->timeline->mutex.dep_map, _THIS_IP_);
- local_irq_restore(flags);
-}
-
-#else
-
-static unsigned long __timeline_mark_lock(struct intel_context *ce)
-{
- return 0;
-}
-
-static void __timeline_mark_unlock(struct intel_context *ce,
- unsigned long flags)
-{
-}
-
-#endif /* !IS_ENABLED(CONFIG_LOCKDEP) */
-
static void duration(struct dma_fence *fence, struct dma_fence_cb *cb)
{
struct i915_request *rq = to_request(fence);
@@ -159,7 +126,6 @@ static bool switch_to_kernel_context(struct intel_engine_cs *engine)
{
struct intel_context *ce = engine->kernel_context;
struct i915_request *rq;
- unsigned long flags;
bool result = true;
/*
@@ -214,7 +180,7 @@ static bool switch_to_kernel_context(struct intel_engine_cs *engine)
* engine->wakeref.count, we may see the request completion and retire
* it causing an underflow of the engine->wakeref.
*/
- flags = __timeline_mark_lock(ce);
+ set_bit(CONTEXT_IS_PARKED, &ce->flags);
GEM_BUG_ON(atomic_read(&ce->timeline->active_count) < 0);
rq = __i915_request_create(ce, GFP_NOWAIT);
@@ -246,7 +212,7 @@ static bool switch_to_kernel_context(struct intel_engine_cs *engine)
result = false;
out_unlock:
- __timeline_mark_unlock(ce, flags);
+ clear_bit(CONTEXT_IS_PARKED, &ce->flags);
return result;
}
@@ -642,7 +642,8 @@ i915_request_timeline(const struct i915_request *rq)
{
/* Valid only while the request is being constructed (or retired). */
return rcu_dereference_protected(rq->timeline,
- lockdep_is_held(&rcu_access_pointer(rq->timeline)->mutex));
+ lockdep_is_held(&rcu_access_pointer(rq->timeline)->mutex) ||
+ test_bit(CONTEXT_IS_PARKED, &rq->context->flags));
}
static inline struct i915_gem_context *
This is a revert of commits d67739268cf0e ("drm/i915/gt: Mark up the nested engine-pm timeline lock as irqsafe") 6c69a45445af9 ("drm/i915/gt: Mark context->active_count as protected by timeline->mutex") The existing code leads to a different behaviour depending on whether lockdep is enabled or not. Any following lock that is acquired without disabling interrupts (but needs to) will not be noticed by lockdep. This it not just a lockdep annotation but is used but an actual mutex_t that is properly used as a lock but in case of __timeline_mark_lock() lockdep is only told that it is acquired but no lock has been acquired. It appears that its purpose is just satisfy the lockdep_assert_held() check in intel_context_mark_active(). The other problem with disabling interrupts is that on PREEMPT_RT interrupts are also disabled which leads to problems for instance later during memory allocation. Add a CONTEXT_IS_PARKED bit to intel_engine_cs and set_bit/clear_bit it instead of mutex_acquire/mutex_release. Use test_bit in the two identified spots which relied on the lockdep annotation. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Suggested--by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- drivers/gpu/drm/i915/gt/intel_context.h | 3 +- drivers/gpu/drm/i915/gt/intel_context_types.h | 1 + drivers/gpu/drm/i915/gt/intel_engine_pm.c | 38 +------------------ drivers/gpu/drm/i915/i915_request.h | 3 +- 4 files changed, 7 insertions(+), 38 deletions(-)