[Intel-gfx] [RFC 37/44] drm/i915: Added facility for cancelling an outstanding request

[John.C.Harrison at Intel.com]

From: John Harrison <John.C.Harrison at Intel.com>

If the scheduler pre-empts a batch buffer that is queued in the ring or even
executing in the ring then that buffer must be returned to the queued in
software state. Part of this re-queueing is to clean up the request structure.
---
 drivers/gpu/drm/i915/i915_drv.h |    1 +
 drivers/gpu/drm/i915/i915_gem.c |   16 ++++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 872e869..f8980c0 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2319,6 +2319,7 @@ int __i915_add_request(struct intel_engine_cs *ring,
 	__i915_add_request(ring, NULL, NULL, seqno, true)
 #define i915_add_request_wo_flush(ring) \
 	__i915_add_request(ring, NULL, NULL, NULL, false)
+int i915_gem_cancel_request(struct intel_engine_cs *ring, u32 seqno);
 int __must_check i915_wait_seqno(struct intel_engine_cs *ring,
 				 uint32_t seqno);
 int i915_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf);
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 1c508b7..dd0fac8 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2655,6 +2655,22 @@ void i915_gem_reset(struct drm_device *dev)
 	i915_gem_restore_fences(dev);
 }
 
+int
+i915_gem_cancel_request(struct intel_engine_cs *ring, u32 seqno)
+{
+	struct drm_i915_gem_request *req, *next;
+	int found = 0;
+
+	list_for_each_entry_safe(req, next, &ring->request_list, list) {
+		if (req->seqno == seqno) {
+			found += 1;
+			i915_gem_free_request(req);
+		}
+	}
+
+	return found;
+}
+
 /**
  * This function clears the request list as sequence numbers are passed.
  */
-- 
1.7.9.5