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, 4 insertions, 105 deletions

diff --git a/drivers/scsi/mvsas/mv_sas.c b/drivers/scsi/mvsas/mv_sas.c
index ac52f7c99513..85d86a5cdb60 100644
--- a/drivers/scsi/mvsas/mv_sas.c
+++ b/drivers/scsi/mvsas/mv_sas.c
@@ -852,43 +852,7 @@ prep_out:
 	return rc;
 }
 
-static struct mvs_task_list *mvs_task_alloc_list(int *num, gfp_t gfp_flags)
-{
-	struct mvs_task_list *first = NULL;
-
-	for (; *num > 0; --*num) {
-		struct mvs_task_list *mvs_list = kmem_cache_zalloc(mvs_task_list_cache, gfp_flags);
-
-		if (!mvs_list)
-			break;
-
-		INIT_LIST_HEAD(&mvs_list->list);
-		if (!first)
-			first = mvs_list;
-		else
-			list_add_tail(&mvs_list->list, &first->list);
-
-	}
-
-	return first;
-}
-
-static inline void mvs_task_free_list(struct mvs_task_list *mvs_list)
-{
-	LIST_HEAD(list);
-	struct list_head *pos, *a;
-	struct mvs_task_list *mlist = NULL;
-
-	__list_add(&list, mvs_list->list.prev, &mvs_list->list);
-
-	list_for_each_safe(pos, a, &list) {
-		list_del_init(pos);
-		mlist = list_entry(pos, struct mvs_task_list, list);
-		kmem_cache_free(mvs_task_list_cache, mlist);
-	}
-}
-
-static int mvs_task_exec(struct sas_task *task, const int num, gfp_t gfp_flags,
+static int mvs_task_exec(struct sas_task *task, gfp_t gfp_flags,
 				struct completion *completion, int is_tmf,
 				struct mvs_tmf_task *tmf)
 {
@@ -912,74 +876,9 @@ static int mvs_task_exec(struct sas_task *task, const int num, gfp_t gfp_flags,
 	return rc;
 }
 
-static int mvs_collector_task_exec(struct sas_task *task, const int num, gfp_t gfp_flags,
-				struct completion *completion, int is_tmf,
-				struct mvs_tmf_task *tmf)
+int mvs_queue_command(struct sas_task *task, gfp_t gfp_flags)
 {
-	struct domain_device *dev = task->dev;
-	struct mvs_prv_info *mpi = dev->port->ha->lldd_ha;
-	struct mvs_info *mvi = NULL;
-	struct sas_task *t = task;
-	struct mvs_task_list *mvs_list = NULL, *a;
-	LIST_HEAD(q);
-	int pass[2] = {0};
-	u32 rc = 0;
-	u32 n = num;
-	unsigned long flags = 0;
-
-	mvs_list = mvs_task_alloc_list(&n, gfp_flags);
-	if (n) {
-		printk(KERN_ERR "%s: mvs alloc list failed.\n", __func__);
-		rc = -ENOMEM;
-		goto free_list;
-	}
-
-	__list_add(&q, mvs_list->list.prev, &mvs_list->list);
-
-	list_for_each_entry(a, &q, list) {
-		a->task = t;
-		t = list_entry(t->list.next, struct sas_task, list);
-	}
-
-	list_for_each_entry(a, &q , list) {
-
-		t = a->task;
-		mvi = ((struct mvs_device *)t->dev->lldd_dev)->mvi_info;
-
-		spin_lock_irqsave(&mvi->lock, flags);
-		rc = mvs_task_prep(t, mvi, is_tmf, tmf, &pass[mvi->id]);
-		if (rc)
-			dev_printk(KERN_ERR, mvi->dev, "mvsas exec failed[%d]!\n", rc);
-		spin_unlock_irqrestore(&mvi->lock, flags);
-	}
-
-	if (likely(pass[0]))
-			MVS_CHIP_DISP->start_delivery(mpi->mvi[0],
-				(mpi->mvi[0]->tx_prod - 1) & (MVS_CHIP_SLOT_SZ - 1));
-
-	if (likely(pass[1]))
-			MVS_CHIP_DISP->start_delivery(mpi->mvi[1],
-				(mpi->mvi[1]->tx_prod - 1) & (MVS_CHIP_SLOT_SZ - 1));
-
-	list_del_init(&q);
-
-free_list:
-	if (mvs_list)
-		mvs_task_free_list(mvs_list);
-
-	return rc;
-}
-
-int mvs_queue_command(struct sas_task *task, const int num,
-			gfp_t gfp_flags)
-{
-	struct mvs_device *mvi_dev = task->dev->lldd_dev;
-	struct sas_ha_struct *sas = mvi_dev->mvi_info->sas;
-
-	if (sas->lldd_max_execute_num < 2)
-		return mvs_task_exec(task, num, gfp_flags, NULL, 0, NULL);
-	else
-		return mvs_collector_task_exec(task, num, gfp_flags, NULL, 0, NULL);
+	return mvs_task_exec(task, gfp_flags, NULL, 0, NULL);
 }
 
 static void mvs_slot_free(struct mvs_info *mvi, u32 rx_desc)
@@ -1411,7 +1310,7 @@ static int mvs_exec_internal_tmf_task(struct domain_device *dev,
 		task->slow_task->timer.expires = jiffies + MVS_TASK_TIMEOUT*HZ;
 		add_timer(&task->slow_task->timer);
 
-		res = mvs_task_exec(task, 1, GFP_KERNEL, NULL, 1, tmf);
+		res = mvs_task_exec(task, GFP_KERNEL, NULL, 1, tmf);
 
 		if (res) {
 			del_timer(&task->slow_task->timer);