drm/nouveau/core/mm: replace region list with next pointer

We never have any need for a double-linked list here, and as there's
generally a large number of these objects, replace it with a single-
linked list in order to save some memory.

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

1 files changed, 4 insertions, 13 deletions

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
index a6a7fa0d7679..a94238374a39 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
@@ -305,11 +305,11 @@ gk20a_instobj_dtor_iommu(struct nvkm_memory *memory)
 	struct gk20a_instobj_iommu *node = gk20a_instobj_iommu(memory);
 	struct gk20a_instmem *imem = node->base.imem;
 	struct device *dev = imem->base.subdev.device->dev;
-	struct nvkm_mm_node *r;
+	struct nvkm_mm_node *r = node->base.mem.mem;
 	unsigned long flags;
 	int i;
 
-	if (unlikely(list_empty(&node->base.mem.regions)))
+	if (unlikely(!r))
 		goto out;
 
 	spin_lock_irqsave(&imem->lock, flags);
@@ -320,9 +320,6 @@ gk20a_instobj_dtor_iommu(struct nvkm_memory *memory)
 
 	spin_unlock_irqrestore(&imem->lock, flags);
 
-	r = list_first_entry(&node->base.mem.regions, struct nvkm_mm_node,
-			     rl_entry);
-
 	/* clear IOMMU bit to unmap pages */
 	r->offset &= ~BIT(imem->iommu_bit - imem->iommu_pgshift);
 
@@ -404,10 +401,7 @@ gk20a_instobj_ctor_dma(struct gk20a_instmem *imem, u32 npages, u32 align,
 	node->r.length = (npages << PAGE_SHIFT) >> 12;
 
 	node->base.mem.offset = node->handle;
-
-	INIT_LIST_HEAD(&node->base.mem.regions);
-	list_add_tail(&node->r.rl_entry, &node->base.mem.regions);
-
+	node->base.mem.mem = &node->r;
 	return 0;
 }
 
@@ -484,10 +478,7 @@ gk20a_instobj_ctor_iommu(struct gk20a_instmem *imem, u32 npages, u32 align,
 	r->offset |= BIT(imem->iommu_bit - imem->iommu_pgshift);
 
 	node->base.mem.offset = ((u64)r->offset) << imem->iommu_pgshift;
-
-	INIT_LIST_HEAD(&node->base.mem.regions);
-	list_add_tail(&r->rl_entry, &node->base.mem.regions);
-
+	node->base.mem.mem = r;
 	return 0;
 
 release_area: