[Intel-gfx] [PATCH 2/7] drm/i915/guc: Kill USES_GUC_SUBMISSION macro

[kbuild test robot]

Hi Daniele,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on drm-intel/for-linux-next]
[cannot apply to drm-tip/drm-tip v5.5-rc7 next-20200124]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Daniele-Ceraolo-Spurio/Commit-early-to-GuC/20200116-112105
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.1-153-g47b6dfef-dirty
        make ARCH=x86_64 allmodconfig
        make C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp at intel.com>


sparse warnings: (new ones prefixed by >>)

>> drivers/gpu/drm/i915/gem/i915_gem_context.c:1457:51: sparse: sparse: dereference of noderef expression

vim +1457 drivers/gpu/drm/i915/gem/i915_gem_context.c

  1440	
  1441	static int
  1442	set_engines__load_balance(struct i915_user_extension __user *base, void *data)
  1443	{
  1444		struct i915_context_engines_load_balance __user *ext =
  1445			container_of_user(base, typeof(*ext), base);
  1446		const struct set_engines *set = data;
  1447		struct intel_engine_cs *stack[16];
  1448		struct intel_engine_cs **siblings;
  1449		struct intel_context *ce;
  1450		u16 num_siblings, idx;
  1451		unsigned int n;
  1452		int err;
  1453	
  1454		if (!HAS_EXECLISTS(set->ctx->i915))
  1455			return -ENODEV;
  1456	
> 1457		if (intel_uc_uses_guc_submission(&set->ctx->vm->gt->uc))
  1458			return -ENODEV; /* not implement yet */
  1459	
  1460		if (get_user(idx, &ext->engine_index))
  1461			return -EFAULT;
  1462	
  1463		if (idx >= set->engines->num_engines) {
  1464			DRM_DEBUG("Invalid placement value, %d >= %d\n",
  1465				  idx, set->engines->num_engines);
  1466			return -EINVAL;
  1467		}
  1468	
  1469		idx = array_index_nospec(idx, set->engines->num_engines);
  1470		if (set->engines->engines[idx]) {
  1471			DRM_DEBUG("Invalid placement[%d], already occupied\n", idx);
  1472			return -EEXIST;
  1473		}
  1474	
  1475		if (get_user(num_siblings, &ext->num_siblings))
  1476			return -EFAULT;
  1477	
  1478		err = check_user_mbz(&ext->flags);
  1479		if (err)
  1480			return err;
  1481	
  1482		err = check_user_mbz(&ext->mbz64);
  1483		if (err)
  1484			return err;
  1485	
  1486		siblings = stack;
  1487		if (num_siblings > ARRAY_SIZE(stack)) {
  1488			siblings = kmalloc_array(num_siblings,
  1489						 sizeof(*siblings),
  1490						 GFP_KERNEL);
  1491			if (!siblings)
  1492				return -ENOMEM;
  1493		}
  1494	
  1495		for (n = 0; n < num_siblings; n++) {
  1496			struct i915_engine_class_instance ci;
  1497	
  1498			if (copy_from_user(&ci, &ext->engines[n], sizeof(ci))) {
  1499				err = -EFAULT;
  1500				goto out_siblings;
  1501			}
  1502	
  1503			siblings[n] = intel_engine_lookup_user(set->ctx->i915,
  1504							       ci.engine_class,
  1505							       ci.engine_instance);
  1506			if (!siblings[n]) {
  1507				DRM_DEBUG("Invalid sibling[%d]: { class:%d, inst:%d }\n",
  1508					  n, ci.engine_class, ci.engine_instance);
  1509				err = -EINVAL;
  1510				goto out_siblings;
  1511			}
  1512		}
  1513	
  1514		ce = intel_execlists_create_virtual(siblings, n);
  1515		if (IS_ERR(ce)) {
  1516			err = PTR_ERR(ce);
  1517			goto out_siblings;
  1518		}
  1519	
  1520		intel_context_set_gem(ce, set->ctx);
  1521	
  1522		if (cmpxchg(&set->engines->engines[idx], NULL, ce)) {
  1523			intel_context_put(ce);
  1524			err = -EEXIST;
  1525			goto out_siblings;
  1526		}
  1527	
  1528	out_siblings:
  1529		if (siblings != stack)
  1530			kfree(siblings);
  1531	
  1532		return err;
  1533	}
  1534	

---
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