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, 7 insertions, 9 deletions

diff --git a/src/gallium/drivers/i965/brw_screen_buffers.c b/src/gallium/drivers/i965/brw_screen_buffers.c
index ba54740225..7ae386ffb3 100644
--- a/src/gallium/drivers/i965/brw_screen_buffers.c
+++ b/src/gallium/drivers/i965/brw_screen_buffers.c
@@ -43,15 +43,11 @@ brw_buffer_unmap( struct pipe_screen *screen,
 static void
 brw_buffer_destroy( struct pipe_buffer *buffer )
 {
-   struct brw_screen *bscreen = brw_screen( buffer->screen );
-   struct brw_winsys_screen *sws = bscreen->sws;
    struct brw_buffer *buf = brw_buffer( buffer );
 
    assert(!p_atomic_read(&buffer->reference.count));
 
-   if (buf->bo)
-      sws->bo_unreference(buf->bo);
-   
+   bo_reference(&buf->bo, NULL);
    FREE(buf);
 }
 
@@ -66,6 +62,7 @@ brw_buffer_create(struct pipe_screen *screen,
    struct brw_winsys_screen *sws = bscreen->sws;
    struct brw_buffer *buf;
    unsigned buffer_type;
+   enum pipe_error ret;
    
    buf = CALLOC_STRUCT(brw_buffer);
    if (!buf)
@@ -101,10 +98,11 @@ brw_buffer_create(struct pipe_screen *screen,
       break;
    }
    
-   buf->bo = sws->bo_alloc( sws,
-                            buffer_type,
-                            size,
-                            alignment );
+   ret = sws->bo_alloc( sws, buffer_type,
+                        size, alignment,
+                        &buf->bo );
+   if (ret != PIPE_OK)
+      return NULL;
       
    return &buf->base; 
 }