i965g: add lots of error checks and early returns

Any allocation that may fail should be checked, and propogate the
error upwards.  At the highest level we will flush batch and retry.

This is an alternate strategy to what the original DRI driver did of
attempting to flush batch from the lowest levels (eg inside
BEGIN_BATCH).  The trouble with that strategy was that flushes could
occur at unexpected times, and additionally there was a need for a
wierd notification mechanism to propogate the 'lost context' state
back up to higher levels.

Propogating the errors directly gives us a lot of flexibility how to
deal with these states, at the expense of a lot more checking in the
code.

Will add some sanity checks later to make sure that out-of-memory
conditions are properly escalated and not lost halfway up the stack.

1 files changed, 5 insertions, 13 deletions

diff --git a/src/gallium/drivers/i965/brw_draw_upload.c b/src/gallium/drivers/i965/brw_draw_upload.c
index 4fa7d549eb..188605a0c1 100644
--- a/src/gallium/drivers/i965/brw_draw_upload.c
+++ b/src/gallium/drivers/i965/brw_draw_upload.c
@@ -251,9 +251,8 @@ static int brw_prepare_vertices(struct brw_context *brw)
       brw->vb.vb[i].vertex_count = (vb->stride == 0 ?
 				    1 :
 				    (bo->size - offset) / vb->stride);
-      brw->sws->bo_unreference(brw->vb.vb[i].bo);
-      brw->vb.vb[i].bo = bo;
-      brw->sws->bo_reference(brw->vb.vb[i].bo);
+
+      bo_reference( &brw->vb.vb[i].bo,  bo );
 
       /* Don't need to retain this reference.  We have a reference on
        * the underlying winsys buffer:
@@ -417,6 +416,7 @@ const struct brw_tracked_state brw_vertices = {
 static int brw_prepare_indices(struct brw_context *brw)
 {
    struct pipe_buffer *index_buffer = brw->curr.index_buffer;
+   struct pipe_buffer *upload_buf = NULL;
    struct brw_winsys_buffer *bo = NULL;
    GLuint offset;
    GLuint index_size;
@@ -438,7 +438,6 @@ static int brw_prepare_indices(struct brw_context *brw)
    /* Turn userbuffer into a proper hardware buffer?
     */
    if (brw_buffer_is_user_buffer(index_buffer)) {
-      struct pipe_buffer *upload_buf;
 
       ret = u_upload_buffer( brw->vb.upload_index,
 			     0,
@@ -450,8 +449,6 @@ static int brw_prepare_indices(struct brw_context *brw)
 	 return ret;
 
       bo = brw_buffer(upload_buf)->bo;
-      brw->sws->bo_reference(bo);
-      pipe_buffer_reference( &upload_buf, NULL );
 
       /* XXX: annotate the userbuffer with the upload information so
        * that successive calls don't get re-uploaded.
@@ -459,8 +456,6 @@ static int brw_prepare_indices(struct brw_context *brw)
    }
    else {
       bo = brw_buffer(index_buffer)->bo;
-      brw->sws->bo_reference(bo);
-      
       ib_size = bo->size;
       offset = 0;
    }
@@ -486,15 +481,12 @@ static int brw_prepare_indices(struct brw_context *brw)
    if (brw->ib.bo != bo ||
        brw->ib.size != ib_size)
    {
-      brw->sws->bo_unreference(brw->ib.bo);
-      brw->ib.bo = bo;
+      bo_reference(&brw->ib.bo, bo);
       brw->ib.size = ib_size;
       brw->state.dirty.brw |= BRW_NEW_INDEX_BUFFER;
    }
-   else {
-      brw->sws->bo_unreference(bo);
-   }
 
+   pipe_buffer_reference( &upload_buf, NULL );
    brw_add_validated_bo(brw, brw->ib.bo);
    return 0;
 }