linux-kernel - Re: [PATCH] scsi: pm8001: Fix running

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Message-ID: <CAMGffE=TnrtRMBZemnfkSf6C63=TkWZfdpeC9Cr29TK__OiM-A@mail.gmail.com>
Date:   Thu, 22 Sep 2022 16:01:55 +0200
From:   Jinpu Wang <jinpu.wang@...os.com>
To:     John Garry <john.garry@...wei.com>
Cc:     jinpu.wang@...os.com, jejb@...ux.ibm.com,
        martin.petersen@...cle.com, linux-kernel@...r.kernel.org,
        linux-scsi@...r.kernel.org, damien.lemoal@...nsource.wdc.com
Subject: Re: [PATCH] scsi: pm8001: Fix running_req for internal abort commands

On Thu, Sep 22, 2022 at 3:57 PM John Garry <john.garry@...wei.com> wrote:
>
> Disabling the remote phy for a SATA disk causes a hang:
>
> root@(none)$ more /sys/class/sas_phy/phy-0:0:8/target_port_protocols
> sata
> root@(none)$ echo 0 > sys/class/sas_phy/phy-0:0:8/enable
> root@(none)$ [   67.855950] sas: ex 500e004aaaaaaa1f phy08 change count has changed
> [   67.920585] sd 0:0:2:0: [sdc] Synchronizing SCSI cache
> [   67.925780] sd 0:0:2:0: [sdc] Synchronize Cache(10) failed: Result: hostbyte=0x04 driverbyte=DRIVER_OK
> [   67.935094] sd 0:0:2:0: [sdc] Stopping disk
> [   67.939305] sd 0:0:2:0: [sdc] Start/Stop Unit failed: Result: hostbyte=0x04 driverbyte=DRIVER_OK
> ...
> [  123.998998] INFO: task kworker/u192:1:642 blocked for more than 30 seconds.
> [  124.005960]   Not tainted 6.0.0-rc1-205202-gf26f8f761e83 #218
> [  124.012049] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> [  124.019872] task:kworker/u192:1  state:D stack:0 pid:  642 ppid: 2 flags:0x00000008
> [  124.028223] Workqueue: 0000:04:00.0_event_q sas_port_event_worker
> [  124.034319] Call trace:
> [  124.036758]  __switch_to+0x128/0x278
> [  124.040333]  __schedule+0x434/0xa58
> [  124.043820]  schedule+0x94/0x138
> [  124.047045]  schedule_timeout+0x2fc/0x368
> [  124.051052]  wait_for_completion+0xdc/0x200
> [  124.055234]  __flush_workqueue+0x1a8/0x708
> [  124.059328]  sas_porte_broadcast_rcvd+0xa8/0xc0
> [  124.063858]  sas_port_event_worker+0x60/0x98
> [  124.068126]  process_one_work+0x3f8/0x660
> [  124.072134]  worker_thread+0x70/0x700
> [  124.075793]  kthread+0x1a4/0x1b8
> [  124.079014]  ret_from_fork+0x10/0x20
>
> The issue is that the per-device running_req read in
> pm8001_dev_gone_notify() never goes to zero and we never make progress.
> This is caused by missing accounting for running_req for when an internal
> abort command completes.
>
> In commit 2cbbf489778e ("scsi: pm8001: Use libsas internal abort support")
> we started to send internal abort commands as a proper sas_task. In this
> when we deliver a sas_task to HW the per-device running_req is incremented
> in pm8001_queue_command(). However it is never decremented for internal
> abort commnds, so decrement in pm8001_mpi_task_abort_resp().
>
> Fixes: 2cbbf489778e ("scsi: pm8001: Use libsas internal abort support")
> Signed-off-by: John Garry <john.garry@...wei.com>
lgtm
Acked-by: Jack Wang <jinpu.wang@...os.com>
>
> diff --git a/drivers/scsi/pm8001/pm8001_hwi.c b/drivers/scsi/pm8001/pm8001_hwi.c
> index 91d78d0a38fe..628b08ba6770 100644
> --- a/drivers/scsi/pm8001/pm8001_hwi.c
> +++ b/drivers/scsi/pm8001/pm8001_hwi.c
> @@ -3612,6 +3612,10 @@ int pm8001_mpi_task_abort_resp(struct pm8001_hba_info *pm8001_ha, void *piomb)
>                 pm8001_dbg(pm8001_ha, FAIL, " TASK NULL. RETURNING !!!\n");
>                 return -1;
>         }
> +
> +       if (t->task_proto == SAS_PROTOCOL_INTERNAL_ABORT)
> +               atomic_dec(&pm8001_dev->running_req);
> +
>         ts = &t->task_status;
>         if (status != 0)
>                 pm8001_dbg(pm8001_ha, FAIL, "task abort failed status 0x%x ,tag = 0x%x, scp= 0x%x\n",
> --
> 2.35.3
>