diff options
| -rw-r--r-- | drivers/gpu/drm/i915/gt/intel_engine.h | 15 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/gt/intel_lrc.c | 13 |
2 files changed, 22 insertions, 6 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_engine.h b/drivers/gpu/drm/i915/gt/intel_engine.h index 29c8c03c5caa..b469de0dd9b6 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine.h +++ b/drivers/gpu/drm/i915/gt/intel_engine.h @@ -107,7 +107,20 @@ execlists_num_ports(const struct intel_engine_execlists * const execlists) static inline struct i915_request * execlists_active(const struct intel_engine_execlists *execlists) { - return *READ_ONCE(execlists->active); + struct i915_request * const *cur, * const *old, *active; + + cur = READ_ONCE(execlists->active); + smp_rmb(); /* pairs with overwrite protection in process_csb() */ + do { + old = cur; + + active = READ_ONCE(*cur); + cur = READ_ONCE(execlists->active); + + smp_rmb(); /* and complete the seqlock retry */ + } while (unlikely(cur != old)); + + return active; } static inline void diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c index 4a1d1c599124..0604b11a2842 100644 --- a/drivers/gpu/drm/i915/gt/intel_lrc.c +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c @@ -2232,6 +2232,7 @@ cancel_port_requests(struct intel_engine_execlists * const execlists) execlists_schedule_out(*port); clear_ports(execlists->inflight, ARRAY_SIZE(execlists->inflight)); + smp_wmb(); /* complete the seqlock for execlists_active() */ WRITE_ONCE(execlists->active, execlists->inflight); } @@ -2386,6 +2387,7 @@ static void process_csb(struct intel_engine_cs *engine) /* Point active to the new ELSP; prevent overwriting */ WRITE_ONCE(execlists->active, execlists->pending); + smp_wmb(); /* notify execlists_active() */ /* cancel old inflight, prepare for switch */ trace_ports(execlists, "preempted", old); @@ -2393,11 +2395,12 @@ static void process_csb(struct intel_engine_cs *engine) execlists_schedule_out(*old++); /* switch pending to inflight */ - WRITE_ONCE(execlists->active, - memcpy(execlists->inflight, - execlists->pending, - execlists_num_ports(execlists) * - sizeof(*execlists->pending))); + memcpy(execlists->inflight, + execlists->pending, + execlists_num_ports(execlists) * + sizeof(*execlists->pending)); + smp_wmb(); /* complete the seqlock */ + WRITE_ONCE(execlists->active, execlists->inflight); WRITE_ONCE(execlists->pending[0], NULL); } else { |