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

Can Guo
2021-01-07T08:03:34Z

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.

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);