[PATCH 1/2] drm/i915: Don't allow setting I915_CONTEXT_PARAM_VM twice

[Jason Ekstrand]

Allowing setting it multiple times brings no real utility to the API, no
userspace relies on it, and it does make i915 a tiny bit more
complicated.  Let's disallow it for now unless someone comes up with a
compelling reason to support it.

Signed-off-by: Jason Ekstrand <jason at jlekstrand.net>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index 7d6f52d8a8012..5853737cc79f3 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -319,7 +319,6 @@ static int set_proto_ctx_vm(struct drm_i915_file_private *fpriv,
 			    const struct drm_i915_gem_context_param *args)
 {
 	struct drm_i915_private *i915 = fpriv->dev_priv;
-	struct i915_address_space *vm;
 
 	if (args->size)
 		return -EINVAL;
@@ -327,17 +326,16 @@ static int set_proto_ctx_vm(struct drm_i915_file_private *fpriv,
 	if (!HAS_FULL_PPGTT(i915))
 		return -ENODEV;
 
+	if (pc->vm)
+		return -EINVAL;
+
 	if (upper_32_bits(args->value))
 		return -ENOENT;
 
-	vm = i915_gem_vm_lookup(fpriv, args->value);
-	if (!vm)
+	pc->vm = i915_gem_vm_lookup(fpriv, args->value);
+	if (!pc->vm)
 		return -ENOENT;
 
-	if (pc->vm)
-		i915_vm_put(pc->vm);
-	pc->vm = vm;
-
 	return 0;
 }
 
-- 
2.31.1