Re: [Qemu-devel] [PATCH] scsi-generic: Simplify error handling code

[Philippe Mathieu-Daudé]

On 01/18/2018 05:20 AM, Paolo Bonzini wrote:
> On 18/01/2018 03:52, Fam Zheng wrote:
>> Coverity doesn't like the ignored return value introduced in
>> 9d3b155186c278 (hw/block: Fix the return type), and other callers are
>> converted already in ceff3e1f01.
>>
>> This one was added lately in d9bcd6f7f23a and missed the train. Do it
>> now.
>>
>> Signed-off-by: Fam Zheng <address@hidden>
>> ---
>>  hw/scsi/scsi-generic.c | 9 +++------
>>  1 file changed, 3 insertions(+), 6 deletions(-)
>>
>> diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
>> index ba70c0dc19..7414fe2d67 100644
>> --- a/hw/scsi/scsi-generic.c
>> +++ b/hw/scsi/scsi-generic.c
>> @@ -482,7 +482,6 @@ static void scsi_generic_realize(SCSIDevice *s, Error 
>> **errp)
>>      int rc;
>>      int sg_version;
>>      struct sg_scsi_id scsiid;
>> -    Error *local_err = NULL;
>>  
>>      if (!s->conf.blk) {
>>          error_setg(errp, "drive property not set");
>> @@ -516,11 +515,9 @@ static void scsi_generic_realize(SCSIDevice *s, Error 
>> **errp)
>>          error_setg(errp, "SG_GET_SCSI_ID ioctl failed");
>>          return;
>>      }
>> -    blkconf_apply_backend_options(&s->conf,
>> -                                  blk_is_read_only(s->conf.blk),
>> -                                  true, &local_err);
>> -    if (local_err) {
>> -        error_propagate(errp, local_err);
>> +    if (!blkconf_apply_backend_options(&s->conf,
>> +                                       blk_is_read_only(s->conf.blk),
>> +                                       true, errp)) {
>>          return;
>>      }
>>  
>>
> 
> I'm not a fan of bool return types, in general (because "!" is often
> success while "< 0" is failure) and especially when there is an Error**;
> I disagree with commit 9d3b155186.  But the function is not in an area I
> maintain so I'm queuing this, thanks.

Do you prefer "if (local_err)" and "if (errp && *errp)" ?

I wondered once if a macro might improve this pattern but thought the
code would get more obscure.