As we need to use a mutex to serialisation i915_active activation (because we want to allow the callback to sleep), we need to push the i915_active.retire into a worker callback in case we get need to retire from an atomic context.
Signed-off-by: Chris Wilson <[email protected]> --- drivers/gpu/drm/i915/i915_active.c | 54 ++++++++++++++++++------ drivers/gpu/drm/i915/i915_active_types.h | 3 ++ 2 files changed, 44 insertions(+), 13 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c index 6a9f8d37f415..f76a2b4ef95d 100644 --- a/drivers/gpu/drm/i915/i915_active.c +++ b/drivers/gpu/drm/i915/i915_active.c @@ -30,18 +30,14 @@ struct active_node { }; static void -active_retire(struct i915_active *ref) +__active_retire(struct i915_active *ref) { struct active_node *it, *n; struct rb_root root; bool retire = false; - GEM_BUG_ON(!atomic_read(&ref->count)); - if (atomic_add_unless(&ref->count, -1, 1)) - return; - - /* One active may be flushed from inside the acquire of another */ - mutex_lock_nested(&ref->mutex, SINGLE_DEPTH_NESTING); + lockdep_assert_held(&ref->mutex); + GEM_BUG_ON(i915_active_is_idle(ref)); /* return the unused nodes to our slabcache -- flushing the allocator */ if (atomic_dec_and_test(&ref->count)) { @@ -63,6 +59,35 @@ active_retire(struct i915_active *ref) } } +static void +active_work(struct work_struct *wrk) +{ + struct i915_active *ref = container_of(wrk, typeof(*ref), work); + + GEM_BUG_ON(!atomic_read(&ref->count)); + if (atomic_add_unless(&ref->count, -1, 1)) + return; + + mutex_lock(&ref->mutex); + __active_retire(ref); +} + +static void +active_retire(struct i915_active *ref) +{ + GEM_BUG_ON(!atomic_read(&ref->count)); + if (atomic_add_unless(&ref->count, -1, 1)) + return; + + /* If we are inside interrupt context (fence signaling), defer */ + if (!mutex_trylock(&ref->mutex)) { + queue_work(system_unbound_wq, &ref->work); + return; + } + + __active_retire(ref); +} + static void node_retire(struct i915_active_request *base, struct i915_request *rq) { @@ -140,6 +165,7 @@ void __i915_active_init(struct drm_i915_private *i915, init_llist_head(&ref->barriers); atomic_set(&ref->count, 0); __mutex_init(&ref->mutex, "i915_active", key); + INIT_WORK(&ref->work, active_work); } int i915_active_ref(struct i915_active *ref, @@ -208,8 +234,10 @@ int i915_active_wait(struct i915_active *ref) if (err) return err; - if (!atomic_add_unless(&ref->count, 1, 0)) - goto unlock; + if (!atomic_add_unless(&ref->count, 1, 0)) { + mutex_unlock(&ref->mutex); + return 0; + } rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) { err = i915_active_request_retire(&it->base, BKL(ref)); @@ -217,9 +245,8 @@ int i915_active_wait(struct i915_active *ref) break; } - active_retire(ref); -unlock: - mutex_unlock(&ref->mutex); + __active_retire(ref); + flush_work(&ref->work); return err; } @@ -260,8 +287,9 @@ int i915_request_await_active(struct i915_request *rq, struct i915_active *ref) #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM) void i915_active_fini(struct i915_active *ref) { - GEM_BUG_ON(!RB_EMPTY_ROOT(&ref->tree)); GEM_BUG_ON(atomic_read(&ref->count)); + GEM_BUG_ON(work_pending(&ref->work)); + GEM_BUG_ON(!RB_EMPTY_ROOT(&ref->tree)); mutex_destroy(&ref->mutex); } #endif diff --git a/drivers/gpu/drm/i915/i915_active_types.h b/drivers/gpu/drm/i915/i915_active_types.h index 5b0a3024ce24..06acdffe0f6d 100644 --- a/drivers/gpu/drm/i915/i915_active_types.h +++ b/drivers/gpu/drm/i915/i915_active_types.h @@ -12,6 +12,7 @@ #include <linux/mutex.h> #include <linux/rbtree.h> #include <linux/rcupdate.h> +#include <linux/workqueue.h> struct drm_i915_private; struct i915_active_request; @@ -39,6 +40,8 @@ struct i915_active { int (*active)(struct i915_active *ref); void (*retire)(struct i915_active *ref); + struct work_struct work; + struct llist_head barriers; }; -- 2.20.1 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
