Re: [PATCH v2] scsi: libsas: defer ata device eh commands to libata

[John Garry <john.garry@xxxxxxxxxx>]

On 07/03/2018 09:18, Jack Wang wrote:
> 2018-03-07 8:47 GMT+01:00 Jason Yan <yanaijie@xxxxxxxxxx>:
> > 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@xxxxxxxxxx>
> > CC: Xiaofei Tan <tanxiaofei@xxxxxxxxxx>
> > CC: John Garry <john.garry@xxxxxxxxxx>
> > CC: Dan Williams <dan.j.williams@xxxxxxxxx>
> Hi Jason,
>
> Would be good if you add the Fixes tag, so distribution could pick it up easily.
> And wasn't the idea to delete sas_eh_finish_cmd instead of sas_eh_defer_cmd?

The problem was that we need to defer any ATA command. So the solution 
was to just delete sas_eh_defer_cmd() and make sas_eh_finish_cmd() do 
what needs to be done for either ATA or non-ATA task.

Thanks,
John

> Thanks,
> Jack
> > ---
> >  drivers/scsi/libsas/sas_scsi_host.c | 30 ++++++++++--------------------
> >  1 file changed, 10 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
> > index 6de9681ace82..fd76436b289c 100644
> > --- a/drivers/scsi/libsas/sas_scsi_host.c
> > +++ b/drivers/scsi/libsas/sas_scsi_host.c
> > @@ -223,6 +223,7 @@ 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
> > @@ -231,6 +232,11 @@ static void sas_eh_finish_cmd(struct scsi_cmnd *cmd)
> >          */
> >         sas_end_task(cmd, task);
> >
> > +       if (dev_is_sata(dev)) {
> > +               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.
> > @@ -238,22 +244,6 @@ 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;
> > @@ -261,7 +251,7 @@ 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);
> >         }
> >  }
> >
> > @@ -631,12 +621,12 @@ 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);
> > @@ -647,7 +637,7 @@ 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;
> >                         }
> > --
> > 2.13.6
>
> .