Re: [PATCH v4 1/2] scsi: ufs: Fix task management request completion timeout

[Can Guo]

On 2021-04-01 00:45, Avri Altman wrote:
> > ufshcd_tmc_handler() calls blk_mq_tagset_busy_iter(fn =
> > ufshcd_compl_tm()),
> > but since blk_mq_tagset_busy_iter() only iterates over all reserved 
> > tags
> > and requests which are not in IDLE state, ufshcd_compl_tm() never gets 
> > a
> > chance to run. Thus, TMR always ends up with completion timeout. Fix 
> > it by
> > calling blk_mq_start_request() in  __ufshcd_issue_tm_cmd().
> >
> > Fixes: 69a6c269c097 ("scsi: ufs: Use blk_{get,put}_request() to 
> > allocate and
> > free TMFs")
> >
> > Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>
> > ---
> >  drivers/scsi/ufs/ufshcd.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > index b49555fa..d4f8cb2 100644
> > --- a/drivers/scsi/ufs/ufshcd.c
> > +++ b/drivers/scsi/ufs/ufshcd.c
> > @@ -6464,6 +6464,7 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba
> > *hba,
> >
> >         spin_lock_irqsave(host->host_lock, flags);
> >         task_tag = hba->nutrs + free_slot;
> > +       blk_mq_start_request(req);
> Maybe just set req->state to MQ_RQ_IN_FLIGHT
> Without all other irrelevant initializations such as add timeout etc.

I don't see any other drivers do that, is it appropriate
to call WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT) outside
block layer?

Thanks,
Can Guo.

> Thanks,
> Avri
> >         treq->req_header.dword_0 |= cpu_to_be32(task_tag);
> >
> > --
> > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a
> > Linux Foundation Collaborative Project.