diff --git a/drivers/gpu/drm/i915/gt/intel_timeline.c b/drivers/gpu/drm/i915/gt/intel_timeline.c index 115a24d4a20a..9d436e14ea8d 100644 --- a/drivers/gpu/drm/i915/gt/intel_timeline.c +++ b/drivers/gpu/drm/i915/gt/intel_timeline.c @@ -500,17 +500,32 @@ int intel_timeline_read_hwsp(struct i915_request *from, struct i915_request *to, u32 *hwsp) { - struct intel_timeline_cacheline *cl = from->hwsp_cacheline; - struct intel_timeline *tl = from->timeline; + struct intel_timeline *tl; int err; + rcu_read_lock(); + tl = rcu_dereference(from->timeline); + if (i915_request_completed(from) || !kref_get_unless_zero(&tl->kref)) + tl = NULL; + rcu_read_unlock(); + if (!tl) /* already completed */ + return 1; + GEM_BUG_ON(rcu_access_pointer(to->timeline) == tl); - mutex_lock_nested(&tl->mutex, SINGLE_DEPTH_NESTING); - err = i915_request_completed(from); - if (!err) + err = -EBUSY; + if (mutex_trylock(&tl->mutex)) { + struct intel_timeline_cacheline *cl = from->hwsp_cacheline; + + if (i915_request_completed(from)) { + err = 1; + goto unlock; + } + err = cacheline_ref(cl, to); - if (!err) { + if (err) + goto unlock; + if (likely(cl == tl->hwsp_cacheline)) { *hwsp = tl->hwsp_offset; } else { /* across a seqno wrap, recover the original offset */ @@ -518,8 +533,11 @@ int intel_timeline_read_hwsp(struct i915_request *from, ptr_unmask_bits(cl->vaddr, CACHELINE_BITS) * CACHELINE_BYTES; } + +unlock: + mutex_unlock(&tl->mutex); } - mutex_unlock(&tl->mutex); + intel_timeline_put(tl); return err; }