Mesa (gallium-0.2): pipebuffer: Ensure refcounts of live buffer objects are never zero.

[Jose Fonseca]

Module: Mesa
Branch: gallium-0.2
Commit: 28a2edb7389107cd46eb382a44d339dd7972310a
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=28a2edb7389107cd46eb382a44d339dd7972310a

Author: José Fonseca <jrfonseca at tungstengraphics.com>
Date:   Tue Oct 28 16:11:09 2008 +0900

pipebuffer: Ensure refcounts of live buffer objects are never zero.

---

 src/gallium/auxiliary/pipebuffer/pb_buffer.h       |   15 ++++++++++++---
 .../auxiliary/pipebuffer/pb_bufmgr_fenced.c        |    3 +--
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/gallium/auxiliary/pipebuffer/pb_buffer.h b/src/gallium/auxiliary/pipebuffer/pb_buffer.h
index 8505d33..19db8a6 100644
--- a/src/gallium/auxiliary/pipebuffer/pb_buffer.h
+++ b/src/gallium/auxiliary/pipebuffer/pb_buffer.h
@@ -177,12 +177,16 @@ pb_get_base_buffer( struct pb_buffer *buf,
 }
 
 
+/**
+ * Don't call this directly. Use pb_reference instead.
+ */
 static INLINE void 
 pb_destroy(struct pb_buffer *buf)
 {
    assert(buf);
    if(!buf)
       return;
+   assert(buf->base.refcount == 0);
    buf->vtbl->destroy(buf);
 }
 
@@ -193,11 +197,16 @@ static INLINE void
 pb_reference(struct pb_buffer **dst,
              struct pb_buffer *src)
 {
-   if (src) 
+   if (src) {
+      assert(src->base.refcount);
       src->base.refcount++;
+   }
 
-   if (*dst && --(*dst)->base.refcount == 0)
-      pb_destroy( *dst );
+   if (*dst) {
+      assert((*dst)->base.refcount);
+      if(--(*dst)->base.refcount == 0)
+         pb_destroy( *dst );
+   }
 
    *dst = src;
 }
diff --git a/src/gallium/auxiliary/pipebuffer/pb_bufmgr_fenced.c b/src/gallium/auxiliary/pipebuffer/pb_bufmgr_fenced.c
index 633ee70..e2594ea 100644
--- a/src/gallium/auxiliary/pipebuffer/pb_bufmgr_fenced.c
+++ b/src/gallium/auxiliary/pipebuffer/pb_bufmgr_fenced.c
@@ -86,8 +86,7 @@ fenced_bufmgr_create_buffer(struct pb_manager *mgr,
    
    fenced_buf = fenced_buffer_create(fenced_mgr->fenced_list, buf);
    if(!fenced_buf) {
-      assert(buf->base.refcount == 1);
-      pb_destroy(buf);
+      pb_reference(&buf, NULL);
    }
    
    return fenced_buf;