Re: [PATCH] SG_SCSI_RESET ioctl: add no_escalate values

[Douglas Gilbert <dgilbert@interlog.com>]

On 13-02-15 04:48 PM, Mike Christie wrote:
> On 02/15/2013 01:39 PM, Douglas Gilbert wrote:
>> Further to the thread titled: "[PATCH] SG_SCSI_RESET ioctl should
>> only perform requested operation" by Jeremy Linton a patch
>> is presented that adds "no_escalate" versions to the existing
>> ioctl. This should not break any existing code.
>>
>> This patches applies to lk 3.7.7 and lk 3.8.0-rc7 . I will extend
>> sg_reset in the sg3_utils package to use it.
>>
>> ChangeLog:
>>    - modify SG_SCSI_RESET ioctl so the SG_SCSI_RESET_NO_ESCALATE
>>      value may be added to the existing values. If so the existing
>>      device->target->bus->host escalation does not occur.
>>    - modify scsi_reset_provider() in the scsi_error.c file in a
>>      similar way to support this new functionality.
>>
>> Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
>
> Some drivers rely on more invasive eh callbacks to be called if they
> return FAILED in a eh callbacks. Is there a way for drivers to tell
> scsi-ml it needs the old behavior?

Mike,
The old behaviour hasn't changed both at the
ioctl(SG_SCSI_RESET) level and the underlying kernel
scsi_reset_provider() function. In both cases extra
values have been added: to third argument of the ioctl
and the second argument ('flag') of the
scsi_reset_provider() function. The existing values
will do exactly the same thing (i.e. escalate) with
the same return values.

The only way it is different is that values that were
previously errors (precisely 0x101 to 0x104) now cause a
non-escalating device(LU)/target/bus reset.

Doug Gilbert