i915: fix i915_set_vertex_buffers() related refcnt imbalance and remove redundancies

Indeed, this resource was assigned twice and was not properly freed.

For instance, this issue is triggered with:
"piglit/bin/glsl-fs-pointcoord -auto -fbo"
while setting GALLIUM_REFCNT_LOG=refcnt.log.

Fixes: 0278d1fa32 ("gallium: add unbind_num_trailing_slots to set_vertex_buffers")
Signed-off-by: Patrick Lerda <patrick9876@free.fr>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27572>

src/gallium/drivers/i915/i915_context.c

@@ -78,14 +78,14 @@ i915_draw_vbo(struct pipe_context *pipe, const struct pipe_draw_info *info,
    /*
     * Map vertex buffers
     */
-   for (i = 0; i < i915->nr_vertex_buffers; i++) {
-      const void *buf = i915->vertex_buffers[i].is_user_buffer
-                           ? i915->vertex_buffers[i].buffer.user
+   for (i = 0; i < draw->pt.nr_vertex_buffers; i++) {
+      const void *buf = draw->pt.vertex_buffer[i].is_user_buffer
+                           ? draw->pt.vertex_buffer[i].buffer.user
                            : NULL;
       if (!buf) {
-         if (!i915->vertex_buffers[i].buffer.resource)
+         if (!draw->pt.vertex_buffer[i].buffer.resource)
             continue;
-         buf = i915_buffer(i915->vertex_buffers[i].buffer.resource)->data;
+         buf = i915_buffer(draw->pt.vertex_buffer[i].buffer.resource)->data;
       }
       draw_set_mapped_vertex_buffer(draw, i, buf, ~0);
    }
@@ -112,13 +112,13 @@ i915_draw_vbo(struct pipe_context *pipe, const struct pipe_draw_info *info,
    /*
     * Do the drawing
     */
-   draw_vbo(i915->draw, info, drawid_offset, NULL, draws, num_draws, 0);
+   draw_vbo(draw, info, drawid_offset, NULL, draws, num_draws, 0);
 
    /*
     * unmap vertex/index buffers
     */
-   for (i = 0; i < i915->nr_vertex_buffers; i++) {
-      draw_set_mapped_vertex_buffer(i915->draw, i, NULL, 0);
+   for (i = 0; i < draw->pt.nr_vertex_buffers; i++) {
+      draw_set_mapped_vertex_buffer(draw, i, NULL, 0);
    }
    if (mapped_indices)
       draw_set_indexes(draw, NULL, 0, 0);
@@ -127,7 +127,7 @@ i915_draw_vbo(struct pipe_context *pipe, const struct pipe_draw_info *info,
     * Instead of flushing on every state change, we flush once here
     * when we fire the vbo.
     */
-   draw_flush(i915->draw);
+   draw_flush(draw);
 }
 
 /*

src/gallium/drivers/i915/i915_context.h

@@ -32,6 +32,7 @@
 #include "pipe/p_defines.h"
 #include "pipe/p_state.h"
 
+#include "draw/draw_private.h"
 #include "draw/draw_vertex.h"
 
 #include "tgsi/tgsi_scan.h"
@@ -272,8 +273,6 @@ struct i915_context {
    void *vs;
 
    struct i915_velems_state *velems;
-   unsigned nr_vertex_buffers;
-   struct pipe_vertex_buffer vertex_buffers[PIPE_MAX_ATTRIBS];
 
    struct pipe_blend_color blend_color;
    struct pipe_stencil_ref stencil_ref;

src/gallium/drivers/i915/i915_state.c

@@ -1001,11 +1001,11 @@ i915_set_vertex_buffers(struct pipe_context *pipe, unsigned count,
    struct i915_context *i915 = i915_context(pipe);
    struct draw_context *draw = i915->draw;
 
-   util_set_vertex_buffers_count(i915->vertex_buffers, &i915->nr_vertex_buffers,
-                                 buffers, count, true);
+   assert(count <= PIPE_MAX_ATTRIBS);
 
-   /* pass-through to draw module */
-   draw_set_vertex_buffers(draw, count, buffers);
+   util_set_vertex_buffers_count(draw->pt.vertex_buffer,
+                                 &draw->pt.nr_vertex_buffers, buffers, count,
+                                 true);
 }
 
 static void *

src/gallium/drivers/i915/i915_surface.c

@@ -60,8 +60,8 @@ i915_util_blitter_save_states(struct i915_context *i915)
    util_blitter_save_viewport(i915->blitter, &i915->viewport);
    util_blitter_save_scissor(i915->blitter, &i915->scissor);
    util_blitter_save_vertex_elements(i915->blitter, i915->velems);
-   util_blitter_save_vertex_buffers(i915->blitter, i915->vertex_buffers,
-                                    i915->nr_vertex_buffers);
+   util_blitter_save_vertex_buffers(i915->blitter, i915->draw->pt.vertex_buffer,
+                                    i915->draw->pt.nr_vertex_buffers);
 
    util_blitter_save_framebuffer(i915->blitter, &i915->framebuffer);