ACK/cmnt: [PATCH][SRU Bionic] scsi: libsas: defer ata device eh commands to libata

[dann frazier]

On Tue, May 8, 2018 at 9:12 AM, Kleber Souza <kleber.souza at canonical.com> wrote:
> On 05/03/18 23:49, dann frazier wrote:
>> From: Jason Yan <yanaijie at huawei.com>
>>
>> BugLink: https://bugs.launchpad.net/bugs/1768971
>>
>> When ata device doing EH, some commands still attached with tasks are
>> not passed to libata when abort failed or recover failed, so libata did
>> not handle these commands. After these commands done, sas task is freed,
>> but ata qc is not freed. This will cause ata qc leak and trigger a
>> warning like below:
>>
>> WARNING: CPU: 0 PID: 28512 at drivers/ata/libata-eh.c:4037
>> ata_eh_finish+0xb4/0xcc
>> CPU: 0 PID: 28512 Comm: kworker/u32:2 Tainted: G     W  OE 4.14.0#1
>> ......
>> Call trace:
>> [<ffff0000088b7bd0>] ata_eh_finish+0xb4/0xcc
>> [<ffff0000088b8420>] ata_do_eh+0xc4/0xd8
>> [<ffff0000088b8478>] ata_std_error_handler+0x44/0x8c
>> [<ffff0000088b8068>] ata_scsi_port_error_handler+0x480/0x694
>> [<ffff000008875fc4>] async_sas_ata_eh+0x4c/0x80
>> [<ffff0000080f6be8>] async_run_entry_fn+0x4c/0x170
>> [<ffff0000080ebd70>] process_one_work+0x144/0x390
>> [<ffff0000080ec100>] worker_thread+0x144/0x418
>> [<ffff0000080f2c98>] kthread+0x10c/0x138
>> [<ffff0000080855dc>] ret_from_fork+0x10/0x18
>>
>> If ata qc leaked too many, ata tag allocation will fail and io blocked
>> for ever.
>>
>> As suggested by Dan Williams, defer ata device commands to libata and
>> merge sas_eh_finish_cmd() with sas_eh_defer_cmd(). libata will handle
>> ata qcs correctly after this.
>>
>> Signed-off-by: Jason Yan <yanaijie at huawei.com>
>> CC: Xiaofei Tan <tanxiaofei at huawei.com>
>> CC: John Garry <john.garry at huawei.com>
>> CC: Dan Williams <dan.j.williams at intel.com>
>> Reviewed-by: Dan Williams <dan.j.williams at intel.com>
>> Signed-off-by: Martin K. Petersen <martin.petersen at oracle.com>
>> (cherry picked from commit 318aaf34f1179b39fa9c30fa0f3288b645beee39)
>> Signed-off-by: dann frazier <dann.frazier at canonical.com>
>> ---
>>  drivers/scsi/libsas/sas_scsi_host.c | 33 ++++++++++++-----------------
>>  1 file changed, 13 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
>> index a68caa0d3fb5..00902c9a34b8 100644
>> --- a/drivers/scsi/libsas/sas_scsi_host.c
>> +++ b/drivers/scsi/libsas/sas_scsi_host.c
>> @@ -222,6 +222,7 @@ int sas_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
>>  static void sas_eh_finish_cmd(struct scsi_cmnd *cmd)
>>  {
>>       struct sas_ha_struct *sas_ha = SHOST_TO_SAS_HA(cmd->device->host);
>> +     struct domain_device *dev = cmd_to_domain_dev(cmd);
>>       struct sas_task *task = TO_SAS_TASK(cmd);
>>
>>       /* At this point, we only get called following an actual abort
>> @@ -230,6 +231,14 @@ static void sas_eh_finish_cmd(struct scsi_cmnd *cmd)
>>        */
>>       sas_end_task(cmd, task);
>>
>> +     if (dev_is_sata(dev)) {
>> +             /* defer commands to libata so that libata EH can
>> +              * handle ata qcs correctly
>> +              */
>> +             list_move_tail(&cmd->eh_entry, &sas_ha->eh_ata_q);
>> +             return;
>> +     }
>> +
>>       /* now finish the command and move it on to the error
>>        * handler done list, this also takes it off the
>>        * error handler pending list.
>> @@ -237,22 +246,6 @@ static void sas_eh_finish_cmd(struct scsi_cmnd *cmd)
>>       scsi_eh_finish_cmd(cmd, &sas_ha->eh_done_q);
>>  }
>>
>> -static void sas_eh_defer_cmd(struct scsi_cmnd *cmd)
>> -{
>> -     struct domain_device *dev = cmd_to_domain_dev(cmd);
>> -     struct sas_ha_struct *ha = dev->port->ha;
>> -     struct sas_task *task = TO_SAS_TASK(cmd);
>> -
>> -     if (!dev_is_sata(dev)) {
>> -             sas_eh_finish_cmd(cmd);
>> -             return;
>> -     }
>> -
>> -     /* report the timeout to libata */
>> -     sas_end_task(cmd, task);
>> -     list_move_tail(&cmd->eh_entry, &ha->eh_ata_q);
>> -}
>> -
>>  static void sas_scsi_clear_queue_lu(struct list_head *error_q, struct scsi_cmnd *my_cmd)
>>  {
>>       struct scsi_cmnd *cmd, *n;
>> @@ -260,7 +253,7 @@ static void sas_scsi_clear_queue_lu(struct list_head *error_q, struct scsi_cmnd
>>       list_for_each_entry_safe(cmd, n, error_q, eh_entry) {
>>               if (cmd->device->sdev_target == my_cmd->device->sdev_target &&
>>                   cmd->device->lun == my_cmd->device->lun)
>> -                     sas_eh_defer_cmd(cmd);
>> +                     sas_eh_finish_cmd(cmd);
>>       }
>>  }
>>
>> @@ -633,12 +626,12 @@ static void sas_eh_handle_sas_errors(struct Scsi_Host *shost, struct list_head *
>>               case TASK_IS_DONE:
>>                       SAS_DPRINTK("%s: task 0x%p is done\n", __func__,
>>                                   task);
>> -                     sas_eh_defer_cmd(cmd);
>> +                     sas_eh_finish_cmd(cmd);
>>                       continue;
>>               case TASK_IS_ABORTED:
>>                       SAS_DPRINTK("%s: task 0x%p is aborted\n",
>>                                   __func__, task);
>> -                     sas_eh_defer_cmd(cmd);
>> +                     sas_eh_finish_cmd(cmd);
>>                       continue;
>>               case TASK_IS_AT_LU:
>>                       SAS_DPRINTK("task 0x%p is at LU: lu recover\n", task);
>> @@ -649,7 +642,7 @@ static void sas_eh_handle_sas_errors(struct Scsi_Host *shost, struct list_head *
>>                                           "recovered\n",
>>                                           SAS_ADDR(task->dev),
>>                                           cmd->device->lun);
>> -                             sas_eh_defer_cmd(cmd);
>> +                             sas_eh_finish_cmd(cmd);
>>                               sas_scsi_clear_queue_lu(work_q, cmd);
>>                               goto Again;
>>                       }
>>
>
> Hi Dann,
>
> Same here, could you please add a "[Fix]" section on the bug description?
>
> Acked-by: Kleber Sacilotto de Souza <kleber.souza at canonical.com>


Done, ta!

  -dann