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, 0 insertions, 21 deletions

diff --git a/drivers/scsi/libsas/sas_init.c b/drivers/scsi/libsas/sas_init.c
index dbc8a793fd86..362da44f2948 100644
--- a/drivers/scsi/libsas/sas_init.c
+++ b/drivers/scsi/libsas/sas_init.c
@@ -45,7 +45,6 @@ struct sas_task *sas_alloc_task(gfp_t flags)
 	struct sas_task *task = kmem_cache_zalloc(sas_task_cache, flags);
 
 	if (task) {
-		INIT_LIST_HEAD(&task->list);
 		spin_lock_init(&task->task_state_lock);
 		task->task_state_flags = SAS_TASK_STATE_PENDING;
 	}
@@ -77,7 +76,6 @@ EXPORT_SYMBOL_GPL(sas_alloc_slow_task);
 void sas_free_task(struct sas_task *task)
 {
 	if (task) {
-		BUG_ON(!list_empty(&task->list));
 		kfree(task->slow_task);
 		kmem_cache_free(sas_task_cache, task);
 	}
@@ -127,11 +125,6 @@ int sas_register_ha(struct sas_ha_struct *sas_ha)
 	spin_lock_init(&sas_ha->phy_port_lock);
 	sas_hash_addr(sas_ha->hashed_sas_addr, sas_ha->sas_addr);
 
-	if (sas_ha->lldd_queue_size == 0)
-		sas_ha->lldd_queue_size = 1;
-	else if (sas_ha->lldd_queue_size == -1)
-		sas_ha->lldd_queue_size = 128; /* Sanity */
-
 	set_bit(SAS_HA_REGISTERED, &sas_ha->state);
 	spin_lock_init(&sas_ha->lock);
 	mutex_init(&sas_ha->drain_mutex);
@@ -157,15 +150,6 @@ int sas_register_ha(struct sas_ha_struct *sas_ha)
 		goto Undo_ports;
 	}
 
-	if (sas_ha->lldd_max_execute_num > 1) {
-		error = sas_init_queue(sas_ha);
-		if (error) {
-			printk(KERN_NOTICE "couldn't start queue thread:%d, "
-			       "running in direct mode\n", error);
-			sas_ha->lldd_max_execute_num = 1;
-		}
-	}
-
 	INIT_LIST_HEAD(&sas_ha->eh_done_q);
 	INIT_LIST_HEAD(&sas_ha->eh_ata_q);
 
@@ -201,11 +185,6 @@ int sas_unregister_ha(struct sas_ha_struct *sas_ha)
 	__sas_drain_work(sas_ha);
 	mutex_unlock(&sas_ha->drain_mutex);
 
-	if (sas_ha->lldd_max_execute_num > 1) {
-		sas_shutdown_queue(sas_ha);
-		sas_ha->lldd_max_execute_num = 1;
-	}
-
 	return 0;
 }