drm/i915: Also drop vm.ref along error paths for vma construction

commit cf1976b11372cac3b57fbae1831f66a4486355d3 upstream.

Not only do we need to release the vm.ref we acquired for the vma on the
duplicate insert branch, but also for the normal error paths, so roll
them all into one.

Reported-by: Andi Shyti <andi.shyti@intel.com>
Suggested-by: Andi Shyti <andi.shyti@intel.com>
Fixes: 2850748ef876 ("drm/i915: Pull i915_vma_pin under the vm->mutex")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Cc: <stable@vger.kernel.org> # v5.5+
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200702211015.29604-1-chris@chris-wilson.co.uk
(cherry picked from commit 03fca66b7a36b52da8915341eee388267f6d5b73)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 25b04bb561aed87c6f29800193b88584c98d1448..1e4bd2d4f019eef5a51aa5309667f03fbffbc0e9 100644 (file)
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -104,6 +104,7 @@ vma_create(struct drm_i915_gem_object *obj,
           struct i915_address_space *vm,
           const struct i915_ggtt_view *view)
 {
+       struct i915_vma *pos = ERR_PTR(-E2BIG);
        struct i915_vma *vma;
        struct rb_node *rb, **p;
 
@@ -184,7 +185,6 @@ vma_create(struct drm_i915_gem_object *obj,
        rb = NULL;
        p = &obj->vma.tree.rb_node;
        while (*p) {
-               struct i915_vma *pos;
                long cmp;
 
                rb = *p;
@@ -196,17 +196,12 @@ vma_create(struct drm_i915_gem_object *obj,
                 * and dispose of ours.
                 */
                cmp = i915_vma_compare(pos, vm, view);
-               if (cmp == 0) {
-                       spin_unlock(&obj->vma.lock);
-                       i915_vm_put(vm);
-                       i915_vma_free(vma);
-                       return pos;
-               }
-
                if (cmp < 0)
                        p = &rb->rb_right;
-               else
+               else if (cmp > 0)
                        p = &rb->rb_left;
+               else
+                       goto err_unlock;
        }
        rb_link_node(&vma->obj_node, rb, p);
        rb_insert_color(&vma->obj_node, &obj->vma.tree);
@@ -229,8 +224,9 @@ vma_create(struct drm_i915_gem_object *obj,
 err_unlock:
        spin_unlock(&obj->vma.lock);
 err_vma:
+       i915_vm_put(vm);
        i915_vma_free(vma);
-       return ERR_PTR(-E2BIG);
+       return pos;
 }
 
 static struct i915_vma *