[bug report] iommu: iommu_get_group_resv_regions

[Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>]

Hello Eric Auger,

The patch 6c65fb318e8b: "iommu: iommu_get_group_resv_regions" from
Jan 19, 2017, leads to the following static checker warning:

	drivers/iommu/iommu.c:215 iommu_insert_device_resv_regions()
	error: uninitialized symbol 'ret'.

drivers/iommu/iommu.c
   203  static int
   204  iommu_insert_device_resv_regions(struct list_head *dev_resv_regions,
   205                                   struct list_head *group_resv_regions)
   206  {
   207          struct iommu_resv_region *entry;
   208          int ret;
   209  
   210          list_for_each_entry(entry, dev_resv_regions, list) {
   211                  ret = iommu_insert_resv_region(entry, group_resv_regions);
   212                  if (ret)
   213                          break;
   214          }
   215          return ret;

On the one hand, it probably doesn't make sense that the dev_resv_regions
would ever be empty, but on the other hand, there some code that assumes
it is possible.  What I mean is that iommu_get_resv_regions() can
basically do nothing if ->get_resv_regions() isn't implemented.

I guess we should probably set ret = -EINVAL here?

   216  }
   217  
   218  int iommu_get_group_resv_regions(struct iommu_group *group,
   219                                   struct list_head *head)
   220  {
   221          struct iommu_device *device;
   222          int ret = 0;
   223  
   224          mutex_lock(&group->mutex);
   225          list_for_each_entry(device, &group->devices, list) {
   226                  struct list_head dev_resv_regions;
   227  
   228                  INIT_LIST_HEAD(&dev_resv_regions);
   229                  iommu_get_resv_regions(device->dev, &dev_resv_regions);
   230                  ret = iommu_insert_device_resv_regions(&dev_resv_regions, head);
   231                  iommu_put_resv_regions(device->dev, &dev_resv_regions);
   232                  if (ret)
   233                          break;
   234          }
   235          mutex_unlock(&group->mutex);
   236          return ret;
   237  }
   238  EXPORT_SYMBOL_GPL(iommu_get_group_resv_regions);


regards,
dan carpenter