Re: [PATCH v2 08/11] util/vfio-helpers: Use error_setg in qemu_vfio_find_[fixed/temp]_iova

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 8/27/21 7:57 AM, Klaus Jensen wrote:
> On Aug 26 21:50, Philippe Mathieu-Daudé wrote:
>> Have qemu_vfio_find_fixed_iova() and qemu_vfio_find_temp_iova()
>> propagate eventual errors to callers.
>>
>> Suggested-by: Klaus Jensen <k.jensen@samsung.com>
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> ---
>>  util/vfio-helpers.c | 14 ++++++++++----
>>  1 file changed, 10 insertions(+), 4 deletions(-)
>>
>> diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c
>> index 306b5a83e48..7de5081dbd3 100644
>> --- a/util/vfio-helpers.c
>> +++ b/util/vfio-helpers.c

>>  static int
>> -qemu_vfio_find_temp_iova(QEMUVFIOState *s, size_t size, uint64_t *iova)
>> +qemu_vfio_find_temp_iova(QEMUVFIOState *s, size_t size, uint64_t *iova,
>> +                         Error **errp)
>>  {
>>      int i;
>>  
>> @@ -718,6 +722,8 @@ qemu_vfio_find_temp_iova(QEMUVFIOState *s, size_t size, uint64_t *iova)
>>              return 0;
>>          }
>>      }
>> +    error_setg(errp, "temporary iova range not found");
>> +
>>      return -ENOMEM;
>>  }

>> @@ -776,7 +782,7 @@ int qemu_vfio_dma_map(QEMUVFIOState *s, void *host, size_t size,
>>              }
>>              qemu_vfio_dump_mappings(s);
>>          } else {
>> -            if (qemu_vfio_find_temp_iova(s, size, &iova0)) {
>> +            if (qemu_vfio_find_temp_iova(s, size, &iova0, errp)) {
>>                  ret = -ENOMEM;
>>                  goto out;
>>              }
> 
> Not related to this patch, but it is slightly confusing that these
> functions actually already return a negative errno, but then we
> overwrite it.

Good point. I'll make it return a boolean.