Before we did some clever tricks to not use the a lock when touching guc_state.sched_state in certain cases. Don't do that, enforce the use of the lock.
Part of this is removing a dead code path from guc_lrc_desc_pin where a context could be deregistered when the aforementioned function was called from the submission path. Remove this dead code and add a GEM_BUG_ON if this path is ever attempted to be used.
v2: (kernel test robo ) - Add __maybe_unused to sched_state_is_init()
Signed-off-by: Matthew Brost matthew.brost@intel.com Reported-by: kernel test robot lkp@intel.com Reviewed-by: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com --- .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 58 ++++++++++--------- 1 file changed, 32 insertions(+), 26 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c index 1cb97e98871c..901d867a4d90 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -151,11 +151,23 @@ static inline void clr_context_registered(struct intel_context *ce)
static inline void init_sched_state(struct intel_context *ce) { - /* Only should be called from guc_lrc_desc_pin() */ + lockdep_assert_held(&ce->guc_state.lock); atomic_set(&ce->guc_sched_state_no_lock, 0); ce->guc_state.sched_state &= SCHED_STATE_BLOCKED_MASK; }
+__maybe_unused +static bool sched_state_is_init(struct intel_context *ce) +{ + /* + * XXX: Kernel contexts can have SCHED_STATE_NO_LOCK_REGISTERED after + * suspend. + */ + return !(atomic_read(&ce->guc_sched_state_no_lock) & + ~SCHED_STATE_NO_LOCK_REGISTERED) && + !(ce->guc_state.sched_state &= ~SCHED_STATE_BLOCKED_MASK); +} + static inline bool context_wait_for_deregister_to_register(struct intel_context *ce) { @@ -166,7 +178,7 @@ context_wait_for_deregister_to_register(struct intel_context *ce) static inline void set_context_wait_for_deregister_to_register(struct intel_context *ce) { - /* Only should be called from guc_lrc_desc_pin() without lock */ + lockdep_assert_held(&ce->guc_state.lock); ce->guc_state.sched_state |= SCHED_STATE_WAIT_FOR_DEREGISTER_TO_REGISTER; } @@ -605,9 +617,7 @@ static void scrub_guc_desc_for_outstanding_g2h(struct intel_guc *guc) bool pending_disable, pending_enable, deregister, destroyed, banned;
xa_for_each(&guc->context_lookup, index, ce) { - /* Flush context */ spin_lock_irqsave(&ce->guc_state.lock, flags); - spin_unlock_irqrestore(&ce->guc_state.lock, flags);
/* * Once we are at this point submission_disabled() is guaranteed @@ -623,6 +633,8 @@ static void scrub_guc_desc_for_outstanding_g2h(struct intel_guc *guc) banned = context_banned(ce); init_sched_state(ce);
+ spin_unlock_irqrestore(&ce->guc_state.lock, flags); + if (pending_enable || destroyed || deregister) { decr_outstanding_submission_g2h(guc); if (deregister) @@ -1323,6 +1335,7 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop) int ret = 0;
GEM_BUG_ON(!engine->mask); + GEM_BUG_ON(!sched_state_is_init(ce));
/* * Ensure LRC + CT vmas are is same region as write barrier is done @@ -1351,7 +1364,6 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop) desc->priority = ce->guc_prio; desc->context_flags = CONTEXT_REGISTRATION_FLAG_KMD; guc_context_policy_init(engine, desc); - init_sched_state(ce);
/* * The context_lookup xarray is used to determine if the hardware @@ -1362,26 +1374,23 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop) * registering this context. */ if (context_registered) { + bool disabled; + unsigned long flags; + trace_intel_context_steal_guc_id(ce); - if (!loop) { + GEM_BUG_ON(!loop); + + /* Seal race with Reset */ + spin_lock_irqsave(&ce->guc_state.lock, flags); + disabled = submission_disabled(guc); + if (likely(!disabled)) { set_context_wait_for_deregister_to_register(ce); intel_context_get(ce); - } else { - bool disabled; - unsigned long flags; - - /* Seal race with Reset */ - spin_lock_irqsave(&ce->guc_state.lock, flags); - disabled = submission_disabled(guc); - if (likely(!disabled)) { - set_context_wait_for_deregister_to_register(ce); - intel_context_get(ce); - } - spin_unlock_irqrestore(&ce->guc_state.lock, flags); - if (unlikely(disabled)) { - reset_lrc_desc(guc, desc_idx); - return 0; /* Will get registered later */ - } + } + spin_unlock_irqrestore(&ce->guc_state.lock, flags); + if (unlikely(disabled)) { + reset_lrc_desc(guc, desc_idx); + return 0; /* Will get registered later */ }
/* @@ -1390,10 +1399,7 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop) */ with_intel_runtime_pm(runtime_pm, wakeref) ret = deregister_context(ce, ce->guc_id, loop); - if (unlikely(ret == -EBUSY)) { - clr_context_wait_for_deregister_to_register(ce); - intel_context_put(ce); - } else if (unlikely(ret == -ENODEV)) { + if (unlikely(ret == -ENODEV)) { ret = 0; /* Will get registered later */ } } else {