ata: libata-eh: queue hotplug work on the system_dfl_long_wq workqueue

ata_scsi_port_error_handler() uses schedule_delayed_work() to queue
the ap->hotplug_task work.

schedule_delayed_work() always uses the system_percpu_wq per-cpu
workqueue.

ata_scsi_scan_host() queues the ap->hotplug_task work on the unbound
system_dfl_long_wq workqueue.

It seems counter-intuitive to queue the same work on two different
workqueues. Thus, change ata_scsi_port_error_handler() to also queue
the ap->hotplug_task work on the system_dfl_long_wq workqueue, such
that the work is always queued on the same workqueue.

Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Niklas Cassel <cassel@kernel.org>

Author: floatious

drivers/ata/libata-eh.c

@@ -819,7 +819,7 @@ void ata_scsi_port_error_handler(struct Scsi_Host *host, struct ata_port *ap)
 		ap->pflags &= ~ATA_PFLAG_LOADING;
 	else if ((ap->pflags & ATA_PFLAG_SCSI_HOTPLUG) &&
 		!(ap->flags & ATA_FLAG_SAS_HOST))
-		schedule_delayed_work(&ap->hotplug_task, 0);
+		queue_delayed_work(system_dfl_long_wq, &ap->hotplug_task, 0);
 
 	if (ap->pflags & ATA_PFLAG_RECOVERED)
 		ata_port_info(ap, "EH complete\n");