On Mon, 2020-03-09 at 14:14 -0400, Ewan D. Milne wrote:
> Large queues of I/O to offline devices that are eventually
> submitted when devices are unblocked result in a many repeated
> "rejecting I/O to offline device" messages. These messages
> can fill up the dmesg buffer in crash dumps so no useful
> prior messages remain. In addition, if a serial console
> is used, the flood of messages can cause a hard lockup in
> the console code.
>
> Introduce a flag indicating the message has already been logged
> for the device, and reset the flag when scsi_device_set_state()
> changes the device state.
>
> Signed-off-by: Ewan D. Milne <emilne@xxxxxxxxxx>
> ---
> drivers/scsi/scsi_lib.c | 8 ++++++--
> include/scsi/scsi_device.h | 2 ++
> 2 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 610ee41..d3a6d97 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -1240,8 +1240,11 @@ scsi_prep_state_check(struct scsi_device
> *sdev, struct request *req)
> * commands. The device must be brought online
> * before trying any recovery commands.
> */
> - sdev_printk(KERN_ERR, sdev,
> - "rejecting I/O to offline device\n");
> + if (!sdev->offline_already) {
> + sdev->offline_already = 1;
> + sdev_printk(KERN_ERR, sdev,
> + "rejecting I/O to offline
> device\n");
> + }
> return BLK_STS_IOERR;
> case SDEV_DEL:
> /*
> @@ -2340,6 +2343,7 @@ scsi_device_set_state(struct scsi_device *sdev,
> enum scsi_device_state state)
> break;
>
> }
> + sdev->offline_already = 0;
> sdev->sdev_state = state;
> return 0;
>
> diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
> index f8312a3..72987a0 100644
> --- a/include/scsi/scsi_device.h
> +++ b/include/scsi/scsi_device.h
> @@ -204,6 +204,8 @@ struct scsi_device {
> unsigned unmap_limit_for_ws:1; /* Use the UNMAP limit for
> WRITE SAME */
> unsigned rpm_autosuspend:1; /* Enable runtime autosuspend
> at device
> * creation time */
> + unsigned offline_already:1; /* Device offline message
> logged */
> +
> atomic_t disk_events_disable_depth; /* disable depth for disk
> events */
>
> DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /*
> supported events */
I tested this on a customer issue.
If its accepted please use
Tested-by: Laurence Oberman <loberman@xxxxxxxxxx>
Reviewed-by: Laurence Oberman <loberman@xxxxxxxxxx>
