On Fri, 2018-03-30 at 15:07 +0530, Chaitra P B wrote:
> diff --git a/drivers/scsi/mpt3sas/mpt3sas_ctl.c 
> b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
> index c1b17d6..2f27d5c 100644
> --- a/drivers/scsi/mpt3sas/mpt3sas_ctl.c
> +++ b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
> @@ -590,7 +590,8 @@ _ctl_set_task_mid(struct MPT3SAS_ADAPTER *ioc, struct 
> mpt3_ioctl_command *karg,
>               struct scsiio_tracker *st;
>  
>               scmd = mpt3sas_scsih_scsi_lookup_get(ioc, smid);
> -             if (!scmd)
> +             if (scmd == NULL || scmd->device == NULL ||
> +                             scmd->device->hostdata == NULL)
>                       continue;
>               if (lun != scmd->device->lun)
>                       continue;

Is _ctl_set_task_mid() always called from the I/O completion path? As
Christoph already wrote, these checks do not make sense in the completion
path.

> @@ -600,6 +601,8 @@ _ctl_set_task_mid(struct MPT3SAS_ADAPTER *ioc, struct 
> mpt3_ioctl_command *karg,
>               if (priv_data->sas_target->handle != handle)
>                       continue;
>               st = scsi_cmd_priv(scmd);
> +             if ((!st) || (st->smid == 0))
> +                     continue;
>               tm_request->TaskMID = cpu_to_le16(st->smid);
>               found = 1;
>       }

Since the I/O submission path guarantees that st->smid != 0, how could
st->smid ever be zero in the I/O completion path?

> diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c 
> b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
> index c9cce65..6b1aaa0 100644
> --- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
> +++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
> @@ -1465,7 +1465,7 @@ mpt3sas_scsih_scsi_lookup_get(struct MPT3SAS_ADAPTER 
> *ioc, u16 smid)
>               scmd = scsi_host_find_tag(ioc->shost, unique_tag);
>               if (scmd) {
>                       st = scsi_cmd_priv(scmd);
> -                     if (st->cb_idx == 0xFF)
> +                     if ((!st) || (st->cb_idx == 0xFF) || (st->smid == 0))
>                               scmd = NULL;
>               }
>       }
> @@ -4451,6 +4451,13 @@ _scsih_flush_running_cmds(struct MPT3SAS_ADAPTER *ioc)
>               count++;
>               _scsih_set_satl_pending(scmd, false);
>               st = scsi_cmd_priv(scmd);
> +             /*
> +              * It may be possible that SCSI scmd got prepared by SML
> +              * but it has not issued to the driver, for these type of
> +              * scmd's don't do anything"
> +              */
> +             if (st && st->smid == 0)
> +                     continue;

This seems wrong to me. If a SCSI command has not been submitted to the
firmware skipping it in this function will introduce a delay because the
command will only be completed after it has timed out and after the SCSI
error handler has finished its processing. I think it's better to complete
the command from this function instead of waiting until for the SCSI error
handler.

Bart.





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