RE: [RFC PATCH v1 1/2] ufs: introduce callbacks to get command information

["Kiwoong Kim" <kwmad.kim@samsung.com>]

> Hi Kiwoong,
> 
> Kiwoong Kim <kwmad.kim@samsung.com> 於 2020年6月26日 週五 下午7:42寫道：
> >
> > > Hi Kiwoong,
> > >
> > > Kiwoong Kim <kwmad.kim@samsung.com> 於 2020年6月20日 週六 下午3:00寫道：
> > > >
> > > > Some SoC specific might need command history for various reasons,
> such
> > > > as stacking command contexts in system memory to check for debugging
> > > > in the future or scaling some DVFS knobs to boost IO throughput.
> > > >
> > > > What you would do with the information could be variant per SoC
> > > > vendor.
> > > >
> > > > Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
> > > > ---
> > > >  drivers/scsi/ufs/ufshcd.c | 4 ++++
> > > >  drivers/scsi/ufs/ufshcd.h | 8 ++++++++
> > > >  2 files changed, 12 insertions(+)
> > > >
> > > > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > > > index 52abe82..0eae3ce 100644
> > > > --- a/drivers/scsi/ufs/ufshcd.c
> > > > +++ b/drivers/scsi/ufs/ufshcd.c
> > > > @@ -2545,6 +2545,8 @@ static int ufshcd_queuecommand(struct
> Scsi_Host
> > > *host, struct scsi_cmnd *cmd)
> > > >         /* issue command to the controller */
> > > >         spin_lock_irqsave(hba->host->host_lock, flags);
> > > >         ufshcd_vops_setup_xfer_req(hba, tag, true);
> > > > +       if (cmd)
> > > > +               ufshcd_vops_cmd_log(hba, cmd, 1);
> > > >         ufshcd_send_command(hba, tag);
> > > >  out_unlock:
> > > >         spin_unlock_irqrestore(hba->host->host_lock, flags); @@
> > > > -4890,6 +4892,8 @@ static void __ufshcd_transfer_req_compl(struct
> > > ufs_hba *hba,
> > > >                         /* Mark completed command as NULL in LRB */
> > > >                         lrbp->cmd = NULL;
> > > >                         lrbp->compl_time_stamp = ktime_get();
> > > > +                       ufshcd_vops_cmd_log(hba, cmd, 2);
> > > > +
> > > >                         /* Do not touch lrbp after scsi done */
> > > >                         cmd->scsi_done(cmd);
> > > >                         __ufshcd_release(hba);
> > >
> > > If your cmd_log vop callbacks are only existed in
> "ufshcd_queuecommand"
> > > and "ufshcd_transfer_req_compl", perhaps you could re-use
> > > "ufshcd_vops_setup_xfer_req()" and an added "ufshcd_vops_compl_req()"
> > > instead of a brand new "ufshcd_vops_cmd_log()" ?
> > >
> > > Thanks,
> > > Stanley Chu
> >
> > Currently, ufshcd_vops_setup_xfer_req doesn't get scsi_cmnd variable.
> 
> You could get scsi_cmnd by hba->lrb[tag].cmd if is_scsi_cmd is true in
> your ufshcd_vops_setup_xfer_req vendor implementation.
> 
> > Actually, when introduced this callback first, I was willing to make it
> do that
> > but someone gave me another idea. Then do you agree to change argument
> set of the function?
> >
> > And I can't find ufshcd_vops_compl_req in 5.9/scsi-queue. Could you let
> me know where to find?
> >
> 
> Sorry to not describing clearly. What I mean is that you could "add"
> ufshcd_vops_compl_xfer_req vop callback in your patch.
> 
> Thanks,
> Stanley Chu

Got it and I'll refer to what you said.
Thanks.
Kiwoong Kim