Re: [PATCH 1/3] scsi: Document enhanced error codes

[Hannes Reinecke <hare@suse.de>]

On 06/06/2013 07:49 AM, Ren Mingxin wrote:
> Hi, Hannes:
>
> I have two questions about the comments:
>
> On 06/05/2013 03:10 PM, Hannes Reinecke wrote:
>> Document the various error codes returned on I/O failure.
>>
>> Signed-off-by: Hannes Reinecke<hare@suse.de>
>> ---
>>   drivers/scsi/scsi_error.c |  7 +++++--
>>   drivers/scsi/scsi_lib.c   | 11 +++++++++++
>>   2 files changed, 16 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
>> index f43de1e..443b0e3 100644
>> --- a/drivers/scsi/scsi_error.c
>> +++ b/drivers/scsi/scsi_error.c
>> @@ -229,8 +229,11 @@ static inline void scsi_eh_prt_fail_stats(struct
>> Scsi_Host *shost,
>>    * scsi_check_sense - Examine scsi cmd sense
>>    * @scmd:    Cmd to have sense checked.
>>    *
>> - * Return value:
>> - *    SUCCESS or FAILED or NEEDS_RETRY or TARGET_ERROR
>> + * Possible return values:
>> + *    SUCCESS
>> + *    FAILED
>> + *    NEEDS_RETRY
>> + *    TARGET_ERROR
>
> This is more likely to be a historical non-update issue -
> there is another possible return value 'ADD_TO_MLQUEUE' which may be
> returned by the handler check_sense() or the case of this
> scsi_check_sense() below, right?
>
>      switch (sshdr.sense_key) {
>      case HARDWARE_ERROR:
>          if (scmd->device->retry_hwerror)
>              return ADD_TO_MLQUEUE;
>
Blast. You are correct. Will be fixing it up.

>>
>>    *
>>    * Notes:
>>    *    When a deferred error is detected the current command has
>> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
>> index 86d5220..12bfa73 100644
>> --- a/drivers/scsi/scsi_lib.c
>> +++ b/drivers/scsi/scsi_lib.c
>> @@ -700,6 +700,17 @@ void scsi_release_buffers(struct scsi_cmnd *cmd)
>>   }
>>   EXPORT_SYMBOL(scsi_release_buffers);
>>
>> +/**
>> + * __scsi_error_from_host_byte - translate SCSI error code into errno
>> + * @cmd:    SCSI command (unused)
>> + * @result:    scsi error code
>> + *
>> + * Translate SCSI error code into standard UNIX errno.
>> + * Return values:
>> + * -ENOLINK    temporary transport failure
>> + * -EREMOTEIO    permanent target failure, do not retry
>> + * -EBADE    permanent nexus failure, retry on other path
>
> Sorry, I'm afraid that I'm not clear why '-EIO' is not listed here...
>
> Perhaps some of them are not necessary to document for some reasons?
>
Hmm. What with EIO being the default I've seen no need to document this.
But yes, you are right, it should be documented.

Cheers,

Hannes