drm/nouveau/ltcg: fix allocating memory as free

Allocating type=0 marks the memory as free. This allows the ltcg memory
to be allocated twice.

Add a BUG_ON in core/mm.c to prevent this ever happening again.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

2 files changed, 5 insertions, 1 deletions

diff --git a/drivers/gpu/drm/nouveau/core/core/mm.c b/drivers/gpu/drm/nouveau/core/core/mm.c
index d8291724dbd4..7a4e0891c5f8 100644
--- a/drivers/gpu/drm/nouveau/core/core/mm.c
+++ b/drivers/gpu/drm/nouveau/core/core/mm.c
@@ -98,6 +98,8 @@ nouveau_mm_head(struct nouveau_mm *mm, u8 type, u32 size_max, u32 size_min,
         u32 splitoff;
         u32 s, e;
 
+        BUG_ON(!type);
+
         list_for_each_entry(this, &mm->free, fl_entry) {
                 e = this->offset + this->length;
                 s = this->offset;
@@ -162,6 +164,8 @@ nouveau_mm_tail(struct nouveau_mm *mm, u8 type, u32 size_max, u32 size_min,
         struct nouveau_mm_node *prev, *this, *next;
         u32 mask = align - 1;
 
+        BUG_ON(!type);
+
         list_for_each_entry_reverse(this, &mm->free, fl_entry) {
                 u32 e = this->offset + this->length;
                 u32 s = this->offset;
diff --git a/drivers/gpu/drm/nouveau/core/subdev/ltcg/nvc0.c b/drivers/gpu/drm/nouveau/core/subdev/ltcg/nvc0.c
index ee2a0beef5e6..cce65cc56514 100644
--- a/drivers/gpu/drm/nouveau/core/subdev/ltcg/nvc0.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/ltcg/nvc0.c
@@ -139,7 +139,7 @@ nvc0_ltcg_init_tag_ram(struct nouveau_fb *pfb, struct nvc0_ltcg_priv *priv)
         tag_size += tag_align;
         tag_size  = (tag_size + 0xfff) >> 12; /* round up */
 
-        ret = nouveau_mm_tail(&pfb->vram, 0, tag_size, tag_size, 1,
+        ret = nouveau_mm_tail(&pfb->vram, 1, tag_size, tag_size, 1,
                               &priv->tag_ram);
         if (ret) {
                 priv->num_tags = 0;