Re: [PATCH] scsi: libsas: Fix disk not being scanned in after being removed

[yangxingui <yangxingui@huawei.com>]

Hi John,

On 2024/2/22 20:41, John Garry wrote:
> On 21/02/2024 07:31, Xingui Yang wrote:
>> As of commit d8649fc1c5e4 ("scsi: libsas: Do discovery on empty PHY to
>> update PHY info"), do discovery will send a new SMP_DISCOVER and update
>> phy->phy_change_count. We found that if the disk is reconnected and phy
>> change_count changes at this time, the disk scanning process will not be
>> triggered.
>>
>> So update the PHY info with the last query results.
>>
>> Fixes: d8649fc1c5e4 ("scsi: libsas: Do discovery on empty PHY to 
>> update PHY info")
>> Signed-off-by: Xingui Yang <yangxingui@huawei.com>
>> ---
>>   drivers/scsi/libsas/sas_expander.c | 9 ++++-----
>>   1 file changed, 4 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/scsi/libsas/sas_expander.c 
>> b/drivers/scsi/libsas/sas_expander.c
>> index a2204674b680..9563f5589948 100644
>> --- a/drivers/scsi/libsas/sas_expander.c
>> +++ b/drivers/scsi/libsas/sas_expander.c
>> @@ -1681,6 +1681,10 @@ int sas_get_phy_attached_dev(struct 
>> domain_device *dev, int phy_id,
>>           if (*type == 0)
>>               memset(sas_addr, 0, SAS_ADDR_SIZE);
>>       }
>> +
>> +    if ((SAS_ADDR(sas_addr) == 0) || (res == -ECOMM))
>> +        sas_set_ex_phy(dev, phy_id, disc_resp);
>> +
>>       kfree(disc_resp);
>>       return res;
>>   }
>> @@ -1972,11 +1976,6 @@ static int sas_rediscover_dev(struct 
>> domain_device *dev, int phy_id,
>>       if ((SAS_ADDR(sas_addr) == 0) || (res == -ECOMM)) {
>>           phy->phy_state = PHY_EMPTY;
>>           sas_unregister_devs_sas_addr(dev, phy_id, last);
>> -        /*
>> -         * Even though the PHY is empty, for convenience we discover
>> -         * the PHY to update the PHY info, like negotiated linkrate.
>> -         */
>> -        sas_ex_phy_discover(dev, phy_id);
> 
> It would be nice to be able to call sas_set_ex_phy() here (instead of 
> sas_get_phy_attached_dev()), but I assume that you can't do that as the 
> disc_resp memory is not available.
> 
By the way, I have updated a version and call sas_set_ex_phy() here, 
please check it again.

Thanks,
Xingui