Re: [PATCH v2 01/15] scsi: Add struct for args to execution functions

[Mike Christie <michael.christie@oracle.com>]

On 12/9/22 4:40 AM, John Garry wrote:
>>        * head injection*required*  here otherwise quiesce won't work
>> @@ -249,13 +238,14 @@ int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
>>       if (unlikely(scmd->resid_len > 0 && scmd->resid_len <= bufflen))
>>           memset(buffer + bufflen - scmd->resid_len, 0, scmd->resid_len);
>>   -    if (resid)
>> -        *resid = scmd->resid_len;
>> -    if (sense && scmd->sense_len)
>> -        memcpy(sense, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
>> -    if (sshdr)
>> -        scsi_normalize_sense(scmd->sense_buffer, scmd->sense_len,
>> -                     sshdr);
>> +    if (args.resid)
>> +        *args.resid = scmd->resid_len;
>> +    if (args.sense && scmd->sense_len)
> 
> I am not sure that you require the sense_len check as you effectively have that same check in scsi_execute_args(), which is the only caller which would have args.sense set. But I suppose __scsi_execute() is still a public API (so should still check); but, by that same token, we have no sanity check for args.sense_len value here then. Is it possible to make __scsi_execute() non-public or move/add the check for proper sense_len here? I'm being extra cautious about this, I suppose.
Do people want the BUILD_BUG_ON we have now or a WARN/BUG?

If we move to a single check in __scsi_execute or some non-macro wrapper
around it then we have to do a WARN/BUG. We do the macro approach now
so we can do the BUILD_BUG_ON.