[SCSI] libsas: fix runaway error handler problem

libsas makes use of scsi_schedule_eh() but forgets to clear the
host_eh_scheduled flag in its error handling routine.  Because of this,
the error handler thread never gets to sleep; it's constantly awake and
trying to run the error routine leading to console spew and inability to
run anything else (at least on a UP system).  The fix is to clear the
flag as we splice the work queue.

Cc: stable@kernel.org
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

drivers/scsi/libsas/sas_scsi_host.c

@@ -646,6 +646,7 @@ void sas_scsi_recover_host(struct Scsi_Host *shost)
 
 	spin_lock_irqsave(shost->host_lock, flags);
 	list_splice_init(&shost->eh_cmd_q, &eh_work_q);
+	shost->host_eh_scheduled = 0;
 	spin_unlock_irqrestore(shost->host_lock, flags);
 
 	SAS_DPRINTK("Enter %s\n", __func__);