[PATCH 6/9] scsi: hpsa: convert private reply queue to blk-mq hw queue

[Ming Lei <ming.lei@redhat.com>]

SCSI's reply qeueue is very similar with blk-mq's hw queue, both
assigned by IRQ vector, so map te private reply queue into blk-mq's hw
queue via .host_tagset.

Then the private reply mapping can be removed.

Another benefit is that the request/irq lost issue may be solved in
generic approach because managed IRQ may be shutdown during CPU
hotplug.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 drivers/scsi/hpsa.c | 49 ++++++++++++++++++---------------------------
 1 file changed, 19 insertions(+), 30 deletions(-)

diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 1bef1da273c2..c7136f9f0ce1 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -51,6 +51,7 @@
 #include <linux/jiffies.h>
 #include <linux/percpu-defs.h>
 #include <linux/percpu.h>
+#include <linux/blk-mq-pci.h>
 #include <asm/unaligned.h>
 #include <asm/div64.h>
 #include "hpsa_cmd.h"
@@ -902,6 +903,18 @@ static ssize_t host_show_legacy_board(struct device *dev,
 	return snprintf(buf, 20, "%d\n", h->legacy_board ? 1 : 0);
 }
 
+static int hpsa_map_queues(struct Scsi_Host *shost)
+{
+	struct ctlr_info *h = shost_to_hba(shost);
+	struct blk_mq_queue_map *qmap = &shost->tag_set.map[HCTX_TYPE_DEFAULT];
+
+	/* Switch to cpu mapping in case that managed IRQ isn't used */
+	if (shost->nr_hw_queues > 1)
+		return blk_mq_pci_map_queues(qmap, h->pdev, 0);
+	else
+		return blk_mq_map_queues(qmap);
+}
+
 static DEVICE_ATTR_RO(raid_level);
 static DEVICE_ATTR_RO(lunid);
 static DEVICE_ATTR_RO(unique_id);
@@ -971,6 +984,7 @@ static struct scsi_host_template hpsa_driver_template = {
 	.slave_alloc		= hpsa_slave_alloc,
 	.slave_configure	= hpsa_slave_configure,
 	.slave_destroy		= hpsa_slave_destroy,
+	.map_queues		= hpsa_map_queues,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl		= hpsa_compat_ioctl,
 #endif
@@ -978,6 +992,7 @@ static struct scsi_host_template hpsa_driver_template = {
 	.shost_attrs = hpsa_shost_attrs,
 	.max_sectors = 2048,
 	.no_write_same = 1,
+	.host_tagset = 1,
 };
 
 static inline u32 next_command(struct ctlr_info *h, u8 q)
@@ -1145,7 +1160,7 @@ static void __enqueue_cmd_and_start_io(struct ctlr_info *h,
 	dial_down_lockup_detection_during_fw_flash(h, c);
 	atomic_inc(&h->commands_outstanding);
 
-	reply_queue = h->reply_map[raw_smp_processor_id()];
+	reply_queue = scsi_cmnd_hctx_index(h->scsi_host, c->scsi_cmd);
 	switch (c->cmd_type) {
 	case CMD_IOACCEL1:
 		set_ioaccel1_performant_mode(h, c, reply_queue);
@@ -5785,6 +5800,9 @@ static int hpsa_scsi_add_host(struct ctlr_info *h)
 {
 	int rv;
 
+	/* map reply queue to blk_mq hw queue */
+	h->scsi_host->nr_hw_queues = h->nreply_queues;
+
 	rv = scsi_add_host(h->scsi_host, &h->pdev->dev);
 	if (rv) {
 		dev_err(&h->pdev->dev, "scsi_add_host failed\n");
@@ -7386,26 +7404,6 @@ static void hpsa_disable_interrupt_mode(struct ctlr_info *h)
 	h->msix_vectors = 0;
 }
 
-static void hpsa_setup_reply_map(struct ctlr_info *h)
-{
-	const struct cpumask *mask;
-	unsigned int queue, cpu;
-
-	for (queue = 0; queue < h->msix_vectors; queue++) {
-		mask = pci_irq_get_affinity(h->pdev, queue);
-		if (!mask)
-			goto fallback;
-
-		for_each_cpu(cpu, mask)
-			h->reply_map[cpu] = queue;
-	}
-	return;
-
-fallback:
-	for_each_possible_cpu(cpu)
-		h->reply_map[cpu] = 0;
-}
-
 /* If MSI/MSI-X is supported by the kernel we will try to enable it on
  * controllers that are capable. If not, we use legacy INTx mode.
  */
@@ -7802,9 +7800,6 @@ static int hpsa_pci_init(struct ctlr_info *h)
 	if (err)
 		goto clean1;
 
-	/* setup mapping between CPU and reply queue */
-	hpsa_setup_reply_map(h);
-
 	err = hpsa_pci_find_memory_BAR(h->pdev, &h->paddr);
 	if (err)
 		goto clean2;	/* intmode+region, pci */
@@ -8516,7 +8511,6 @@ static struct workqueue_struct *hpsa_create_controller_wq(struct ctlr_info *h,
 
 static void hpda_free_ctlr_info(struct ctlr_info *h)
 {
-	kfree(h->reply_map);
 	kfree(h);
 }
 
@@ -8528,11 +8522,6 @@ static struct ctlr_info *hpda_alloc_ctlr_info(void)
 	if (!h)
 		return NULL;
 
-	h->reply_map = kcalloc(nr_cpu_ids, sizeof(*h->reply_map), GFP_KERNEL);
-	if (!h->reply_map) {
-		kfree(h);
-		return NULL;
-	}
 	return h;
 }
 
-- 
2.20.1