Re: drivers/virtio/virtio_mem.c:1031 virtio_mem_mb_plug_any_sb() error: uninitialized symbol 'rc'.

[David Hildenbrand <dhildenb@redhat.com>]

> Am 08.08.2020 um 13:39 schrieb kernel test robot <lkp@intel.com>:
> 
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   449dc8c97089a6e09fb2dac4d92b1b7ac0eb7c1e
> commit: 5f1f79bbc9e26fa9412fa9522f957bb8f030c442 virtio-mem: Paravirtualized memory hotplug
> date:   9 weeks ago
> config: x86_64-randconfig-m001-20200808 (attached as .config)
> compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 

Was there a delay in sending these out? The fix by Dan is long upstream: 1c3d69ab5348

> New smatch warnings:
> drivers/virtio/virtio_mem.c:1031 virtio_mem_mb_plug_any_sb() error: uninitialized symbol 'rc'.
> drivers/gpu/drm/amd/amdgpu/../display/dc/calcs/dce_calcs.c:1607 calculate_bandwidth() warn: Function too hairy.  No more merges.
> 
> Old smatch warnings:
> drivers/gpu/drm/amd/amdgpu/../display/dc/calcs/dce_calcs.c:3387 bw_calcs() warn: inconsistent indenting
> 
> vim +/rc +1031 drivers/virtio/virtio_mem.c
> 
>   978    
>   979    /*
>   980     * Try to plug the desired number of subblocks of a memory block that
>   981     * is already added to Linux.
>   982     *
>   983     * Will modify the state of the memory block.
>   984     *
>   985     * Note: Can fail after some subblocks were successfully plugged.
>   986     */
>   987    static int virtio_mem_mb_plug_any_sb(struct virtio_mem *vm, unsigned long mb_id,
>   988                         uint64_t *nb_sb, bool online)
>   989    {
>   990        unsigned long pfn, nr_pages;
>   991        int sb_id, count;
>   992        int rc;
>   993    
>   994        if (WARN_ON_ONCE(!*nb_sb))
>   995            return -EINVAL;
>   996    
>   997        while (*nb_sb) {
>   998            sb_id = virtio_mem_mb_first_unplugged_sb(vm, mb_id);
>   999            if (sb_id >= vm->nb_sb_per_mb)
>  1000                break;
>  1001            count = 1;
>  1002            while (count < *nb_sb &&
>  1003                   sb_id + count < vm->nb_sb_per_mb &&
>  1004                   !virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id + count,
>  1005                                  1))
>  1006                count++;
>  1007    
>  1008            rc = virtio_mem_mb_plug_sb(vm, mb_id, sb_id, count);
>  1009            if (rc)
>  1010                return rc;
>  1011            *nb_sb -= count;
>  1012            if (!online)
>  1013                continue;
>  1014    
>  1015            /* fake-online the pages if the memory block is online */
>  1016            pfn = PFN_DOWN(virtio_mem_mb_id_to_phys(mb_id) +
>  1017                       sb_id * vm->subblock_size);
>  1018            nr_pages = PFN_DOWN(count * vm->subblock_size);
>  1019            virtio_mem_fake_online(pfn, nr_pages);
>  1020        }
>  1021    
>  1022        if (virtio_mem_mb_test_sb_plugged(vm, mb_id, 0, vm->nb_sb_per_mb)) {
>  1023            if (online)
>  1024                virtio_mem_mb_set_state(vm, mb_id,
>  1025                            VIRTIO_MEM_MB_STATE_ONLINE);
>  1026            else
>  1027                virtio_mem_mb_set_state(vm, mb_id,
>  1028                            VIRTIO_MEM_MB_STATE_OFFLINE);
>  1029        }
>  1030    
>> 1031        return rc;
>  1032    }
>  1033    
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
> <.config.gz>