On 8/18/2021 11:16 PM, Matthew Brost wrote:
Lock the xarray and take ref to the context if needed.
v2:
(Checkpatch)
- Add new line after declaration
(Daniel Vetter)
- Correct put / get accounting in xa_for_loops
Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
---
.../gpu/drm/i915/gt/uc/intel_guc_submission.c | 103 +++++++++++++++---
1 file changed, 88 insertions(+), 15 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 509b298e7cf3..5f77f25322ca 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -606,8 +606,18 @@ static void scrub_guc_desc_for_outstanding_g2h(struct intel_guc *guc)
unsigned long index, flags;
bool pending_disable, pending_enable, deregister, destroyed, banned;
+ xa_lock_irqsave(&guc->context_lookup, flags);
xa_for_each(&guc->context_lookup, index, ce) {
- spin_lock_irqsave(&ce->guc_state.lock, flags);
+ /*
+ * Corner case where the ref count on the object is zero but and
+ * deregister G2H was lost. In this case we don't touch the ref
+ * count and finish the destroy of the context.
+ */
+ bool do_put = kref_get_unless_zero(&ce->ref);
+
+ xa_unlock(&guc->context_lookup);
+
+ spin_lock(&ce->guc_state.lock);
/*
* Once we are at this point submission_disabled() is guaranteed
@@ -623,7 +633,9 @@ 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);
+ spin_unlock(&ce->guc_state.lock);
+
+ GEM_BUG_ON(!do_put && !destroyed);
if (pending_enable || destroyed || deregister) {
decr_outstanding_submission_g2h(guc);
@@ -646,13 +658,19 @@ static void scrub_guc_desc_for_outstanding_g2h(struct intel_guc *guc)
}
intel_context_sched_disable_unpin(ce);
decr_outstanding_submission_g2h(guc);
- spin_lock_irqsave(&ce->guc_state.lock, flags);
+
+ spin_lock(&ce->guc_state.lock);
guc_blocked_fence_complete(ce);
- spin_unlock_irqrestore(&ce->guc_state.lock, flags);
+ spin_unlock(&ce->guc_state.lock);
intel_context_put(ce);
}
+
+ if (do_put)
+ intel_context_put(ce);
is it safe to do the put outside the xa_lock, in case the refcount goes
to zero with this? I know it is unlikely because the refcount was > 0 if
do_put is true, but it might've gone down between us checking earlier
and now.
+ xa_lock(&guc->context_lookup);
}
+ xa_unlock_irqrestore(&guc->context_lookup, flags);
}
static inline bool
@@ -873,16 +891,29 @@ void intel_guc_submission_reset(struct intel_guc *guc, bool stalled)
{
struct intel_context *ce;
unsigned long index;
+ unsigned long flags;
if (unlikely(!guc_submission_initialized(guc))) {
/* Reset called during driver load? GuC not yet initialised! */
return;
}
- xa_for_each(&guc->context_lookup, index, ce)
+ xa_lock_irqsave(&guc->context_lookup, flags);
+ xa_for_each(&guc->context_lookup, index, ce) {
+ if (!kref_get_unless_zero(&ce->ref))
+ continue;
+
+ xa_unlock(&guc->context_lookup);
+
if (intel_context_is_pinned(ce))
__guc_reset_context(ce, stalled);
+ intel_context_put(ce);
+
+ xa_lock(&guc->context_lookup);
+ }
+ xa_unlock_irqrestore(&guc->context_lookup, flags);
+
/* GuC is blown away, drop all references to contexts */
xa_destroy(&guc->context_lookup);
}
@@ -957,11 +988,24 @@ void intel_guc_submission_cancel_requests(struct intel_guc *guc)
{
struct intel_context *ce;
unsigned long index;
+ unsigned long flags;
+
+ xa_lock_irqsave(&guc->context_lookup, flags);
+ xa_for_each(&guc->context_lookup, index, ce) {
+ if (!kref_get_unless_zero(&ce->ref))
+ continue;
+
+ xa_unlock(&guc->context_lookup);
- xa_for_each(&guc->context_lookup, index, ce)
if (intel_context_is_pinned(ce))
guc_cancel_context_requests(ce);
+ intel_context_put(ce);
+
+ xa_lock(&guc->context_lookup);
+ }
+ xa_unlock_irqrestore(&guc->context_lookup, flags);
+
guc_cancel_sched_engine_requests(guc->sched_engine);
/* GuC is blown away, drop all references to contexts */
@@ -2850,21 +2894,28 @@ void intel_guc_find_hung_context(struct intel_engine_cs *engine)
struct intel_context *ce;
struct i915_request *rq;
unsigned long index;
+ unsigned long flags;
/* Reset called during driver load? GuC not yet initialised! */
if (unlikely(!guc_submission_initialized(guc)))
return;
+ xa_lock_irqsave(&guc->context_lookup, flags);
xa_for_each(&guc->context_lookup, index, ce) {
- if (!intel_context_is_pinned(ce))
+ if (!kref_get_unless_zero(&ce->ref))
continue;
+ xa_unlock(&guc->context_lookup);
+
+ if (!intel_context_is_pinned(ce))
+ goto next;
+
if (intel_engine_is_virtual(ce->engine)) {
if (!(ce->engine->mask & engine->mask))
- continue;
+ goto next;
} else {
if (ce->engine != engine)
- continue;
+ goto next;
}
list_for_each_entry(rq, &ce->guc_active.requests, sched.link) {
@@ -2874,9 +2925,17 @@ void intel_guc_find_hung_context(struct intel_engine_cs *engine)
intel_engine_set_hung_context(engine, ce);
/* Can only cope with one hang at a time... */
- return;
+ intel_context_put(ce);
+ xa_lock(&guc->context_lookup);
+ goto done;
}
+next:
+ intel_context_put(ce);
+ xa_lock(&guc->context_lookup);
+
nit: extra newline
Daniele
}
+done:
+ xa_unlock_irqrestore(&guc->context_lookup, flags);
}
void intel_guc_dump_active_requests(struct intel_engine_cs *engine,
@@ -2892,23 +2951,34 @@ void intel_guc_dump_active_requests(struct intel_engine_cs *engine,
if (unlikely(!guc_submission_initialized(guc)))
return;
+ xa_lock_irqsave(&guc->context_lookup, flags);
xa_for_each(&guc->context_lookup, index, ce) {
- if (!intel_context_is_pinned(ce))
+ if (!kref_get_unless_zero(&ce->ref))
continue;
+ xa_unlock(&guc->context_lookup);
+
+ if (!intel_context_is_pinned(ce))
+ goto next;
+
if (intel_engine_is_virtual(ce->engine)) {
if (!(ce->engine->mask & engine->mask))
- continue;
+ goto next;
} else {
if (ce->engine != engine)
- continue;
+ goto next;
}
- spin_lock_irqsave(&ce->guc_active.lock, flags);
+ spin_lock(&ce->guc_active.lock);
intel_engine_dump_active_requests(&ce->guc_active.requests,
hung_rq, m);
- spin_unlock_irqrestore(&ce->guc_active.lock, flags);
+ spin_unlock(&ce->guc_active.lock);
+
+next:
+ intel_context_put(ce);
+ xa_lock(&guc->context_lookup);
}
+ xa_unlock_irqrestore(&guc->context_lookup, flags);
}
void intel_guc_submission_print_info(struct intel_guc *guc,
@@ -2962,7 +3032,9 @@ void intel_guc_submission_print_context_info(struct intel_guc *guc,
{
struct intel_context *ce;
unsigned long index;
+ unsigned long flags;
+ xa_lock_irqsave(&guc->context_lookup, flags);
xa_for_each(&guc->context_lookup, index, ce) {
drm_printf(p, "GuC lrc descriptor %u:\n", ce->guc_id);
drm_printf(p, "\tHW Context Desc: 0x%08x\n", ce->lrc.lrca);
@@ -2981,6 +3053,7 @@ void intel_guc_submission_print_context_info(struct intel_guc *guc,
guc_log_context_priority(p, ce);
}
+ xa_unlock_irqrestore(&guc->context_lookup, flags);
}
static struct intel_context *
