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>

3 files changed, 5 insertions, 136 deletions

diff --git a/drivers/scsi/mvsas/mv_init.c b/drivers/scsi/mvsas/mv_init.c
index ac7c03078409..f15df3de6790 100644
--- a/drivers/scsi/mvsas/mv_init.c
+++ b/drivers/scsi/mvsas/mv_init.c
@@ -26,18 +26,9 @@
 
 #include "mv_sas.h"
 
-static int lldd_max_execute_num = 1;
-module_param_named(collector, lldd_max_execute_num, int, S_IRUGO);
-MODULE_PARM_DESC(collector, "\n"
-	"\tIf greater than one, tells the SAS Layer to run in Task Collector\n"
-	"\tMode.  If 1 or 0, tells the SAS Layer to run in Direct Mode.\n"
-	"\tThe mvsas SAS LLDD supports both modes.\n"
-	"\tDefault: 1 (Direct Mode).\n");
-
 int interrupt_coalescing = 0x80;
 
 static struct scsi_transport_template *mvs_stt;
-struct kmem_cache *mvs_task_list_cache;
 static const struct mvs_chip_info mvs_chips[] = {
 	[chip_6320] =	{ 1, 2, 0x400, 17, 16, 6,  9, &mvs_64xx_dispatch, },
 	[chip_6440] =	{ 1, 4, 0x400, 17, 16, 6,  9, &mvs_64xx_dispatch, },
@@ -513,14 +504,11 @@ static void  mvs_post_sas_ha_init(struct Scsi_Host *shost,
 
 	sha->num_phys = nr_core * chip_info->n_phy;
 
-	sha->lldd_max_execute_num = lldd_max_execute_num;
-
 	if (mvi->flags & MVF_FLAG_SOC)
 		can_queue = MVS_SOC_CAN_QUEUE;
 	else
 		can_queue = MVS_CHIP_SLOT_SZ;
 
-	sha->lldd_queue_size = can_queue;
 	shost->sg_tablesize = min_t(u16, SG_ALL, MVS_MAX_SG);
 	shost->can_queue = can_queue;
 	mvi->shost->cmd_per_lun = MVS_QUEUE_SIZE;
@@ -833,16 +821,7 @@ static int __init mvs_init(void)
 	if (!mvs_stt)
 		return -ENOMEM;
 
-	mvs_task_list_cache = kmem_cache_create("mvs_task_list", sizeof(struct mvs_task_list),
-							 0, SLAB_HWCACHE_ALIGN, NULL);
-	if (!mvs_task_list_cache) {
-		rc = -ENOMEM;
-		mv_printk("%s: mvs_task_list_cache alloc failed! \n", __func__);
-		goto err_out;
-	}
-
 	rc = pci_register_driver(&mvs_pci_driver);
-
 	if (rc)
 		goto err_out;
 
@@ -857,7 +836,6 @@ static void __exit mvs_exit(void)
 {
 	pci_unregister_driver(&mvs_pci_driver);
 	sas_release_transport(mvs_stt);
-	kmem_cache_destroy(mvs_task_list_cache);
 }
 
 struct device_attribute *mvst_host_attrs[] = {
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);
diff --git a/drivers/scsi/mvsas/mv_sas.h b/drivers/scsi/mvsas/mv_sas.h
index d6b19dc80bee..dc409c04747a 100644
--- a/drivers/scsi/mvsas/mv_sas.h
+++ b/drivers/scsi/mvsas/mv_sas.h
@@ -65,7 +65,6 @@ extern struct mvs_tgt_initiator mvs_tgt;
 extern struct mvs_info *tgt_mvi;
 extern const struct mvs_dispatch mvs_64xx_dispatch;
 extern const struct mvs_dispatch mvs_94xx_dispatch;
-extern struct kmem_cache *mvs_task_list_cache;
 
 #define DEV_IS_EXPANDER(type)	\
 	((type == SAS_EDGE_EXPANDER_DEVICE) || (type == SAS_FANOUT_EXPANDER_DEVICE))
@@ -440,12 +439,6 @@ struct mvs_task_exec_info {
 	int n_elem;
 };
 
-struct mvs_task_list {
-	struct sas_task *task;
-	struct list_head list;
-};
-
-
 /******************** function prototype *********************/
 void mvs_get_sas_addr(void *buf, u32 buflen);
 void mvs_tag_clear(struct mvs_info *mvi, u32 tag);
@@ -462,8 +455,7 @@ void mvs_set_sas_addr(struct mvs_info *mvi, int port_id, u32 off_lo,
 		      u32 off_hi, u64 sas_addr);
 void mvs_scan_start(struct Scsi_Host *shost);
 int mvs_scan_finished(struct Scsi_Host *shost, unsigned long time);
-int mvs_queue_command(struct sas_task *task, const int num,
-			gfp_t gfp_flags);
+int mvs_queue_command(struct sas_task *task, gfp_t gfp_flags);
 int mvs_abort_task(struct sas_task *task);
 int mvs_abort_task_set(struct domain_device *dev, u8 *lun);
 int mvs_clear_aca(struct domain_device *dev, u8 *lun);