drm/i915/gvt: fix uninitialized return in intel_gvt_update_reg_whitelist()

Smatch found an uninitialized variable bug in this code:

    drivers/gpu/drm/i915/gvt/cmd_parser.c:3191 intel_gvt_update_reg_whitelist()
    error: uninitialized symbol 'ret'.

The first thing that Smatch complains about is that "ret" isn't set if
we don't enter the "for_each_engine(engine, &dev_priv->gt, id) {" loop.
Presumably we always have at least one engine so that's a false
positive.

But it's definitely a bug to not set "ret" if i915_gem_object_pin_map()
fails.

Let's fix the bug and silence the false positive.

Fixes: 493f30cd086e ("drm/i915/gvt: parse init context to update cmd accessible reg whitelist")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/YA6F3oF8mRaNQWjb@mwanda
(cherry picked from commit 784f70e17e6bc423a04fb6524634a76f68ab1192)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/i915/gvt/cmd_parser.c b/drivers/gpu/drm/i915/gvt/cmd_parser.c
index 7fb91de..d54ea0e 100644 (file)
--- a/drivers/gpu/drm/i915/gvt/cmd_parser.c
+++ b/drivers/gpu/drm/i915/gvt/cmd_parser.c
@@ -3103,7 +3103,7 @@ void intel_gvt_update_reg_whitelist(struct intel_vgpu *vgpu)
        struct intel_vgpu_submission *s = &vgpu->submission;
        struct i915_request *requests[I915_NUM_ENGINES] = {};
        bool is_ctx_pinned[I915_NUM_ENGINES] = {};
-       int ret;
+       int ret = 0;
 
        if (gvt->is_reg_whitelist_updated)
                return;
@@ -3157,6 +3157,7 @@ void intel_gvt_update_reg_whitelist(struct intel_vgpu *vgpu)
                if (IS_ERR(vaddr)) {
                        gvt_err("failed to pin init ctx obj, ring=%d, err=%lx\n",
                                id, PTR_ERR(vaddr));
+                       ret = PTR_ERR(vaddr);
                        goto out;
                }