[Mesa-dev] [PATCH 1/6] u_upload_mgr: rework the application of alignment

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

The function only aligned the size, but not the offset.
The offset was aligned only when the previous suballocation was aligned.
That yielded the correct offset alignment if the alignment was constant
for all suballocations.

Instead, directly align the offset, but allow an unaligned size.
There is no change in behavior, because the alignment is constant
at the moment.

This a prerequisite for allowing a variable alignment for suballocations.
---
 src/gallium/auxiliary/util/u_upload_mgr.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/gallium/auxiliary/util/u_upload_mgr.c b/src/gallium/auxiliary/util/u_upload_mgr.c
index b672fad..4148bae 100644
--- a/src/gallium/auxiliary/util/u_upload_mgr.c
+++ b/src/gallium/auxiliary/util/u_upload_mgr.c
@@ -185,15 +185,20 @@ u_upload_alloc(struct u_upload_mgr *upload,
                struct pipe_resource **outbuf,
                void **ptr)
 {
-   unsigned alloc_size = align(size, upload->alignment);
-   unsigned alloc_offset = align(min_out_offset, upload->alignment);
+   unsigned alignment = upload->alignment;
    unsigned buffer_size = upload->buffer ? upload->buffer->width0 : 0;
    unsigned offset;
 
+   min_out_offset = align(min_out_offset, alignment);
+
+   offset = align(upload->offset, alignment);
+   offset = MAX2(offset, min_out_offset);
+
    /* Make sure we have enough space in the upload buffer
-    * for the sub-allocation. */
-   if (unlikely(MAX2(upload->offset, alloc_offset) + alloc_size > buffer_size)) {
-      u_upload_alloc_buffer(upload, alloc_offset + alloc_size);
+    * for the sub-allocation.
+    */
+   if (unlikely(!upload->buffer || offset + size > buffer_size)) {
+      u_upload_alloc_buffer(upload, min_out_offset + size);
 
       if (unlikely(!upload->buffer)) {
          *out_offset = ~0;
@@ -202,11 +207,10 @@ u_upload_alloc(struct u_upload_mgr *upload,
          return;
       }
 
+      offset = min_out_offset;
       buffer_size = upload->buffer->width0;
    }
 
-   offset = MAX2(upload->offset, alloc_offset);
-
    if (unlikely(!upload->map)) {
       upload->map = pipe_buffer_map_range(upload->pipe, upload->buffer,
                                           offset,
@@ -224,8 +228,8 @@ u_upload_alloc(struct u_upload_mgr *upload,
       upload->map -= offset;
    }
 
-   assert(offset < upload->buffer->width0);
-   assert(offset + size <= upload->buffer->width0);
+   assert(offset < buffer_size);
+   assert(offset + size <= buffer_size);
    assert(size);
 
    /* Emit the return values: */
@@ -233,7 +237,7 @@ u_upload_alloc(struct u_upload_mgr *upload,
    pipe_resource_reference(outbuf, upload->buffer);
    *out_offset = offset;
 
-   upload->offset = offset + alloc_size;
+   upload->offset = offset + size;
 }
 
 void u_upload_data(struct u_upload_mgr *upload,
-- 
2.1.4