libsas: remove task_collector mode

The task_collector mode (or "latency_injector", (C) Dan Willians) is an
optional I/O path in libsas that queues up scsi commands instead of
directly sending it to the hardware.  It generall increases latencies
to in the optiomal case slightly reduce mmio traffic to the hardware.

Only the obsolete aic94xx driver and the mvsas driver allowed to use
it without recompiling the kernel, and most drivers didn't support it
at all.

Remove the giant blob of code to allow better optimizations for scsi-mq
in the future.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 1 insertions, 8 deletions

diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index 766098af4eb7..577770fdee86 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -171,7 +171,6 @@ static void sas_ata_task_done(struct sas_task *task)
 	spin_unlock_irqrestore(ap->lock, flags);
 
 qc_already_gone:
-	list_del_init(&task->list);
 	sas_free_task(task);
 }
 
@@ -244,12 +243,7 @@ static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc)
 	if (qc->scsicmd)
 		ASSIGN_SAS_TASK(qc->scsicmd, task);
 
-	if (sas_ha->lldd_max_execute_num < 2)
-		ret = i->dft->lldd_execute_task(task, 1, GFP_ATOMIC);
-	else
-		ret = sas_queue_up(task);
-
-	/* Examine */
+	ret = i->dft->lldd_execute_task(task, GFP_ATOMIC);
 	if (ret) {
 		SAS_DPRINTK("lldd_execute_task returned: %d\n", ret);
 
@@ -485,7 +479,6 @@ static void sas_ata_internal_abort(struct sas_task *task)
 
 	return;
  out:
-	list_del_init(&task->list);
 	sas_free_task(task);
 }