drm/nouveau: allow creation of zero-sized mm

Useful for places where a given chipset may or may not have a given
resource, and we want to avoid having to spray checks for the mm's
existance around everywhere.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/core/core/mm.c b/drivers/gpu/drm/nouveau/core/core/mm.c
index 4d62064..a6d3cd6 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/core/mm.c
+++ b/drivers/gpu/drm/nouveau/core/core/mm.c
@@ -218,13 +218,16 @@ nouveau_mm_init(struct nouveau_mm *mm, u32 offset, u32 length, u32 block)
        node = kzalloc(sizeof(*node), GFP_KERNEL);
        if (!node)
                return -ENOMEM;
-       node->offset = roundup(offset, mm->block_size);
-       node->length = rounddown(offset + length, mm->block_size) - node->offset;
+
+       if (length) {
+               node->offset  = roundup(offset, mm->block_size);
+               node->length  = rounddown(offset + length, mm->block_size);
+               node->length -= node->offset;
+       }
 
        list_add_tail(&node->nl_entry, &mm->nodes);
        list_add_tail(&node->fl_entry, &mm->free);
        mm->heap_nodes++;
-       mm->heap_size += length;
        return 0;
 }
 

diff --git a/drivers/gpu/drm/nouveau/core/include/core/mm.h b/drivers/gpu/drm/nouveau/core/include/core/mm.h
index 9ee9bf4..975137b 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/include/core/mm.h
+++ b/drivers/gpu/drm/nouveau/core/include/core/mm.h
@@ -19,7 +19,6 @@ struct nouveau_mm {
 
        u32 block_size;
        int heap_nodes;
-       u32 heap_size;
 };
 
 int  nouveau_mm_init(struct nouveau_mm *, u32 offset, u32 length, u32 block);