It is useful to be able to wait on pending rendering without grabbing
the struct_mutex. We can do this by using the i915_gem_active_get_rcu()
primitive to acquire a reference to the pending request without
requiring struct_mutex, just the RCU read lock, and then call
__i915_wait_request().
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_request.h | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_gem_request.h b/drivers/gpu/drm/i915/i915_gem_request.h
index 6aa246848894..006f212b7fd6 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.h
+++ b/drivers/gpu/drm/i915/i915_gem_request.h
@@ -476,6 +476,27 @@ i915_gem_active_wait(const struct i915_gem_active *active, struct mutex *mutex)
return i915_wait_request(request);
}
+static inline int
+i915_gem_active_wait_unlocked(const struct i915_gem_active *active,
+ bool interruptible,
+ s64 *timeout,
+ struct intel_rps_client *rps)
+{
+ struct drm_i915_gem_request *request;
+ int ret = 0;
+
+ rcu_read_lock();
+ request = i915_gem_active_get_rcu(active);
+ rcu_read_unlock();
+
+ if (request) {
+ ret = __i915_wait_request(request, interruptible, timeout, rps);
+ i915_gem_request_put(request);
+ }
+
+ return ret;
+}
+
/**
* i915_gem_active_retire - waits until the request is retired
* @active - the active request on which to wait
--
2.8.1
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