Re: [PATCH v4 2/2] scsi: ufs: handle LINERESET with correct tm_cmd

Jaegeuk Kim
2021-01-07T18:56:13Z

On 01/07, Can Guo wrote:
> On 2021-01-07 16:46, Jaegeuk Kim wrote:
> > On 01/07, Can Guo wrote:
> > > On 2021-01-07 16:07, Jaegeuk Kim wrote:
> > > > On 01/07, Can Guo wrote:
> > > > > On 2021-01-07 15:47, Jaegeuk Kim wrote:
> > > > > > From: Jaegeuk Kim <jaegeuk@google.com>
> > > > > >
> > > > > > This fixes a warning caused by wrong reserve tag usage in
> > > > > > __ufshcd_issue_tm_cmd.
> > > > > >
> > > > > > WARNING: CPU: 7 PID: 7 at block/blk-core.c:630 blk_get_request+0x68/0x70
> > > > > > WARNING: CPU: 4 PID: 157 at block/blk-mq-tag.c:82
> > > > > > blk_mq_get_tag+0x438/0x46c
> > > > > >
> > > > > > And, in ufshcd_err_handler(), we can avoid to send tm_cmd before
> > > > > > aborting
> > > > > > outstanding commands by waiting a bit for IO completion like this.
> > > > > >
> > > > > > __ufshcd_issue_tm_cmd: task management cmd 0x80 timed-out
> > > > > >
> > > > > > Fixes: 69a6c269c097 ("scsi: ufs: Use blk_{get,put}_request() to
> > > > > > allocate and free TMFs")
> > > > > > Fixes: 2355b66ed20c ("scsi: ufs: Handle LINERESET indication in err
> > > > > > handler")
> > > > >
> > > > > Hi Jaegeuk,
> > > > >
> > > > > Sorry, what is wrong with commit 2355b66ed20c? Clearing pending I/O
> > > > > reqs is a general procedure for handling all non-fatal errors.
> > > >
> > > > Without waiting IOs, I hit the below timeout all the time from
> > > > LINERESET, which
> > > > causes UFS stuck permanently, as mentioned in the description.
> > > >
> > > > "__ufshcd_issue_tm_cmd: task management cmd 0x80 timed-out"
> > >
> > > In that case, ufshcd_try_to_abort_task(), the caller of
> > > __ufshcd_issue_tm_cmd(),
> > > should return -ETIMEOUT, then err_handler would jump to do a full
> > > reset,
> > > then bail.
> > > I am not sure what gets UFS stuck permanently. Could you please
> > > share the
> > > callstack
> > > if possible? I really want to know what is happening. Thanks.
> >
> > I can't share all the log tho, it entered full reset. While printing out
> > whole registers, the device was hard reset. Thanks,
>
> Hi Jaegeuk,
>
> Entering full reset is expected in this case, which is why I am saying
> line-reset handling logic should not be penalized. I think we need to
> find out what caused the hard reset but not just adding a delay before
> clearing pending reqs, because let's say 3 sec expires and you hit the
> same tm req timeout (maybe with a lower possibility), you may still end
> up same at the hard reset. You don't need to share all the log, just the
> last call stacks before hard reset. Is it a QCOM's platform used in your
> case? Can you check the log/dump if NoC error happened?

Hi Can,

I figured out it is caused by verbose kernel logs printed in terminal.
I posted v5, so could you please review it?

Thanks,

>
> Thanks.
> Can Guo.
>
> >
> > >
> > > Regards,
> > > Can Guo.
> > >
> > > >
> > > > >
> > > > > Thanks,
> > > > > Can Guo.
> > > > >
> > > > > > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> > > > > > ---
> > > > > > drivers/scsi/ufs/ufshcd.c | 35 +++++++++++++++++++++++++++++++----
> > > > > > 1 file changed, 31 insertions(+), 4 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > > > > > index e6e7bdf99cd7..340dd5e515dd 100644
> > > > > > --- a/drivers/scsi/ufs/ufshcd.c
> > > > > > +++ b/drivers/scsi/ufs/ufshcd.c
> > > > > > @@ -44,6 +44,9 @@
> > > > > > /* Query request timeout */
> > > > > > #define QUERY_REQ_TIMEOUT 1500 /* 1.5 seconds */
> > > > > >
> > > > > > +/* LINERESET TIME OUT */
> > > > > > +#define LINERESET_IO_TIMEOUT_MS (30000) /* 30 sec */
> > > > > > +
> > > > > > /* Task management command timeout */
> > > > > > #define TM_CMD_TIMEOUT 100 /* msecs */
> > > > > >
> > > > > > @@ -5826,6 +5829,7 @@ static void ufshcd_err_handler(struct work_struct
> > > > > > *work)
> > > > > > int err = 0, pmc_err;
> > > > > > int tag;
> > > > > > bool needs_reset = false, needs_restore = false;
> > > > > > + ktime_t start;
> > > > > >
> > > > > > hba = container_of(work, struct ufs_hba, eh_work);
> > > > > >
> > > > > > @@ -5911,6 +5915,22 @@ static void ufshcd_err_handler(struct work_struct
> > > > > > *work)
> > > > > > }
> > > > > >
> > > > > > hba->silence_err_logs = true;
> > > > > > +
> > > > > > + /* Wait for IO completion for non-fatal errors to avoid aborting IOs
> > > > > > */
> > > > > > + start = ktime_get();
> > > > > > + while (hba->outstanding_reqs) {
> > > > > > + ufshcd_complete_requests(hba);
> > > > > > + spin_unlock_irqrestore(hba->host->host_lock, flags);
> > > > > > + schedule();
> > > > > > + spin_lock_irqsave(hba->host->host_lock, flags);
> > > > > > + if (ktime_to_ms(ktime_sub(ktime_get(), start)) >
> > > > > > + LINERESET_IO_TIMEOUT_MS) {
> > > > > > + dev_err(hba->dev, "%s: timeout, outstanding=0x%lx\n",
> > > > > > + __func__, hba->outstanding_reqs);
> > > > > > + break;
> > > > > > + }
> > > > > > + }
> > > > > > +
> > > > > > /* release lock as clear command might sleep */
> > > > > > spin_unlock_irqrestore(hba->host->host_lock, flags);
> > > > > > /* Clear pending transfer requests */
> > > > > > @@ -6302,9 +6322,13 @@ static irqreturn_t ufshcd_intr(int irq, void
> > > > > > *__hba)
> > > > > > intr_status = ufshcd_readl(hba, REG_INTERRUPT_STATUS);
> > > > > > }
> > > > > >
> > > > > > - if (enabled_intr_status && retval == IRQ_NONE) {
> > > > > > - dev_err(hba->dev, "%s: Unhandled interrupt 0x%08x\n",
> > > > > > - __func__, intr_status);
> > > > > > + if (enabled_intr_status && retval == IRQ_NONE &&
> > > > > > + !ufshcd_eh_in_progress(hba)) {
> > > > > > + dev_err(hba->dev, "%s: Unhandled interrupt 0x%08x (0x%08x,
> > > > > > 0x%08x)\n",
> > > > > > + __func__,
> > > > > > + intr_status,
> > > > > > + hba->ufs_stats.last_intr_status,
> > > > > > + enabled_intr_status);
> > > > > > ufshcd_dump_regs(hba, 0, UFSHCI_REG_SPACE_SIZE, "host_regs: ");
> > > > > > }
> > > > > >
> > > > > > @@ -6348,7 +6372,10 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba
> > > > > > *hba,
> > > > > > * Even though we use wait_event() which sleeps indefinitely,
> > > > > > * the maximum wait time is bounded by %TM_CMD_TIMEOUT.
> > > > > > */
> > > > > > - req = blk_get_request(q, REQ_OP_DRV_OUT, BLK_MQ_REQ_RESERVED);
> > > > > > + req = blk_get_request(q, REQ_OP_DRV_OUT, 0);
> > > > > > + if (IS_ERR(req))
> > > > > > + return PTR_ERR(req);
> > > > > > +
> > > > > > req->end_io_data = &wait;
> > > > > > free_slot = req->tag;
> > > > > > WARN_ON_ONCE(free_slot < 0 || free_slot >= hba->nutmrs);