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SubjectRe: [PATCH v2 6/7] scsi: libsas: reset the phy address if discover failed
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On 31/01/2019 02:13, Jason Yan wrote:
>
>
> On 2019/1/31 1:36, John Garry wrote:
>> On 30/01/2019 08:24, Jason Yan wrote:
>>> When we failed to discover the device, the phy address is still kept

/s/phy/PHY/

>>> in ex_phy. So when the next time we revalidate this phy the
>>> address and device type is the same, it will be considered as flutter
>>> and will not be discovered again. So the device will not be brought up.
>>>
>>> Fix this by reset the phy address to the initial value. Then
>>> in the next revalidation the device will be discovered agian.
>>
>> Why fail to discover the device? I wonder in which scenario you have
>> seen this, such that it is worth rediscovery.
>>
>
> The test guys have seen this for several times, especially after LLDD
> changed the logic of lldd_dev_found and may return error now.

We're finding that a specific SATA disk stays in STP pending for some
time and we fail the init in lldd dev found, like you say.

However, I think that we should ensure that this passes, as with your
change I find we get some looping of dev found and lost until it finally
recovers.

Regardless, I think that your change on its own is ok, so:
Reviewed-by: John Garry <john.garry@huawei.com>


>
>
>>>
>>> Tested-by: Chen Liangfei <chenliangfei1@huawei.com>
>>> Signed-off-by: Jason Yan <yanaijie@huawei.com>
>>> CC: Xiaofei Tan <tanxiaofei@huawei.com>
>>> CC: John Garry <john.garry@huawei.com>
>>> CC: Johannes Thumshirn <jthumshirn@suse.de>
>>> CC: Ewan Milne <emilne@redhat.com>
>>> CC: Christoph Hellwig <hch@lst.de>
>>> CC: Tomas Henzl <thenzl@redhat.com>
>>> CC: Dan Williams <dan.j.williams@intel.com>
>>> CC: Hannes Reinecke <hare@suse.com>
>>> ---
>>> drivers/scsi/libsas/sas_expander.c | 7 +++++++
>>> 1 file changed, 7 insertions(+)
>>>
>>> diff --git a/drivers/scsi/libsas/sas_expander.c
>>> b/drivers/scsi/libsas/sas_expander.c
>>> index 6e56ebdc2148..e781941a7088 100644
>>> --- a/drivers/scsi/libsas/sas_expander.c
>>> +++ b/drivers/scsi/libsas/sas_expander.c
>>> @@ -1100,6 +1100,13 @@ static int sas_ex_discover_dev(struct
>>> domain_device *dev, int phy_id)
>>> i, SAS_ADDR(ex->ex_phy[i].attached_sas_addr));
>>> }
>>> }
>>> + } else {
>>> + /* if we failed to discover this device, we have to
>>> + * reset the expander phy attached address so that we
>>> + * will not treat the phy as flutter in the next
>>> + * revalidation
>>> + */
>>> + memset(ex_phy->attached_sas_addr, 0, SAS_ADDR_SIZE);
>>> }
>>>
>>> return res;
>>>
>>
>>
>>
>> .
>>
>
>
> .
>


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