[RFC PATCH 36/42] drm/i915: Teach execbuf there can be more than one batch in the objects list

[Matthew Brost <matthew.brost@xxxxxxxxx>]

In case of multiple batches all batches will be at the beginning on the exec
objects array or at the end based on the existing execbuffer2 flag.

Batches not executed in the current execbuf call will not be processed for
relocations or but will be pinned in same manner as the current batch.

This will enable multiple do_execbuf calls with a single exec object array
in a later patch.

Suggested-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
---
 .../gpu/drm/i915/gem/i915_gem_execbuffer.c    | 31 +++++++++++++------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index 707e12725f74..fe3242f4f2e6 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -255,6 +255,9 @@ struct i915_execbuffer {
 	/* batch_index in vma list */
 	unsigned int batch_index;
 
+	/* number of batches in execbuf IOCTL */
+	unsigned int num_batches;
+
 	/** actual size of execobj[] as we may extend it for the cmdparser */
 	unsigned int buffer_count;
 
@@ -511,6 +514,14 @@ static bool platform_has_relocs_enabled(const struct i915_execbuffer *eb)
 	return false;
 }
 
+static inline bool
+is_batch_buffer(struct i915_execbuffer *eb, unsigned buffer_idx)
+{
+	return eb->args->flags & I915_EXEC_BATCH_FIRST ?
+		buffer_idx <= eb->num_batches :
+		buffer_idx >= eb->args->buffer_count - eb->num_batches;
+}
+
 static int
 eb_validate_vma(struct i915_execbuffer *eb,
 		struct drm_i915_gem_exec_object2 *entry,
@@ -562,11 +573,10 @@ eb_validate_vma(struct i915_execbuffer *eb,
 
 static void
 eb_add_vma(struct i915_execbuffer *eb,
-	   unsigned int i, unsigned batch_idx,
-	   struct i915_vma *vma)
+	   unsigned int buffer_idx, struct i915_vma *vma)
 {
-	struct drm_i915_gem_exec_object2 *entry = &eb->exec[i];
-	struct eb_vma *ev = &eb->vma[i];
+	struct drm_i915_gem_exec_object2 *entry = &eb->exec[buffer_idx];
+	struct eb_vma *ev = &eb->vma[buffer_idx];
 
 	ev->vma = vma;
 	ev->exec = entry;
@@ -591,14 +601,15 @@ eb_add_vma(struct i915_execbuffer *eb,
 	 * Note that actual hangs have only been observed on gen7, but for
 	 * paranoia do it everywhere.
 	 */
-	if (i == batch_idx) {
+	if (is_batch_buffer(eb, buffer_idx)) {
 		if (entry->relocation_count &&
 		    !(ev->flags & EXEC_OBJECT_PINNED))
 			ev->flags |= __EXEC_OBJECT_NEEDS_BIAS;
 		if (eb->reloc_cache.has_fence)
 			ev->flags |= EXEC_OBJECT_NEEDS_FENCE;
 
-		eb->batch = ev;
+		if (buffer_idx == eb->batch_index)
+			eb->batch = ev;
 	}
 }
 
@@ -872,7 +883,7 @@ static int eb_lookup_vmas(struct i915_execbuffer *eb)
 			goto err;
 		}
 
-		eb_add_vma(eb, i, eb->batch_index, vma);
+		eb_add_vma(eb, i, vma);
 
 		if (i915_gem_object_is_userptr(vma->obj)) {
 			err = i915_gem_object_userptr_submit_init(vma->obj);
@@ -3147,6 +3158,7 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 		       struct drm_i915_gem_execbuffer2 *args,
 		       struct drm_i915_gem_exec_object2 *exec,
 		       int batch_index,
+		       unsigned int num_batches,
 		       struct dma_fence *in_fence,
 		       struct dma_fence *exec_fence,
 		       struct dma_fence **out_fence)
@@ -3203,6 +3215,7 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 
 	GEM_BUG_ON(!eb.lut_size);
 
+	eb.num_batches = num_batches;
 	if (batch_index >= 0)
 		eb.batch_index = batch_index;
 
@@ -3433,8 +3446,8 @@ i915_gem_execbuffer2_ioctl(struct drm_device *dev, void *data,
 		goto err_copy;
 	}
 
-	err = i915_gem_do_execbuffer(dev, file, args, exec2_list, -1, in_fence,
-				     exec_fence, out_fence_p);
+	err = i915_gem_do_execbuffer(dev, file, args, exec2_list, -1, 1,
+				     in_fence, exec_fence, out_fence_p);
 
 	/*
 	 * Now that we have begun execution of the batchbuffer, we ignore
-- 
2.28.0