On 2/26/22 3:04 PM, Mike Christie wrote:
> When the iscsi class was added upstream blocking a queue was fast because
> it just set some flag bits and didn't handle IO that was in the process
> of being sent to the driver. That's no longer the case so blocking a queue
> is expensive and we can end up with a backlog of blocks by the time we
> have relogged in and are trying to start the queues.
>
> For the session unblock case, this has try to cancel the block and
> recovery work in case they are still queued so we can avoid unneeded queue
> manipulations. For removal we also now try to cancel all the recovery
> related works since a couple lines down we will set the session and device
> state so running those functions are not necessary.
>
> Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
> ---
> drivers/scsi/scsi_transport_iscsi.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
> index c58126e8cd88..732938f5436b 100644
> --- a/drivers/scsi/scsi_transport_iscsi.c
> +++ b/drivers/scsi/scsi_transport_iscsi.c
> @@ -1944,7 +1944,8 @@ static void __iscsi_unblock_session(struct work_struct *work)
> */
> void iscsi_unblock_session(struct iscsi_cls_session *session)
> {
> - flush_work(&session->block_work);
> + if (!cancel_work_sync(&session->block_work))
> + cancel_delayed_work_sync(&session->recovery_work);
>
> queue_work(iscsi_eh_timer_workq, &session->unblock_work);
> /*
> @@ -2177,9 +2178,9 @@ void iscsi_remove_session(struct iscsi_cls_session *session)
> list_del(&session->sess_list);
> spin_unlock_irqrestore(&sesslock, flags);
>
> - flush_work(&session->block_work);
> - flush_work(&session->unblock_work);
> - cancel_delayed_work_sync(&session->recovery_work);
> + if (!cancel_work_sync(&session->block_work))
> + cancel_delayed_work_sync(&session->recovery_work);
> + cancel_work_sync(&session->unblock_work);
> /*
> * If we are blocked let commands flow again. The lld or iscsi
> * layer should set up the queuecommand to fail commands.
Reviewed-by: Chris Leech <cleech@xxxxxxxxxx>
