[PATCH 15/17] xsysace: convert to blk-mq

[Jens Axboe <axboe@kernel.dk>]

Straight forward conversion, using an internal list to enable the
driver to pull requests at will.

Cc: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 drivers/block/xsysace.c | 91 ++++++++++++++++++++++++++++++-----------
 1 file changed, 66 insertions(+), 25 deletions(-)

diff --git a/drivers/block/xsysace.c b/drivers/block/xsysace.c
index c24589414c75..ddaa362ffe82 100644
--- a/drivers/block/xsysace.c
+++ b/drivers/block/xsysace.c
@@ -88,7 +88,7 @@
 #include <linux/kernel.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
-#include <linux/blkdev.h>
+#include <linux/blk-mq.h>
 #include <linux/mutex.h>
 #include <linux/ata.h>
 #include <linux/hdreg.h>
@@ -209,6 +209,8 @@ struct ace_device {
 	struct device *dev;
 	struct request_queue *queue;
 	struct gendisk *gd;
+	struct blk_mq_tag_set tag_set;
+	struct list_head rq_list;
 
 	/* Inserted CF card parameters */
 	u16 cf_id[ATA_ID_WORDS];
@@ -462,18 +464,26 @@ static inline void ace_fsm_yieldirq(struct ace_device *ace)
 	ace->fsm_continue_flag = 0;
 }
 
+static bool ace_has_next_request(struct request_queue *q)
+{
+	struct ace_device *ace = q->queuedata;
+
+	return !list_empty(&ace->rq_list);
+}
+
 /* Get the next read/write request; ending requests that we don't handle */
 static struct request *ace_get_next_request(struct request_queue *q)
 {
-	struct request *req;
+	struct ace_device *ace = q->queuedata;
+	struct request *rq;
 
-	while ((req = blk_peek_request(q)) != NULL) {
-		if (!blk_rq_is_passthrough(req))
-			break;
-		blk_start_request(req);
-		__blk_end_request_all(req, BLK_STS_IOERR);
+	rq = list_first_entry_or_null(&ace->rq_list, struct request, queuelist);
+	if (rq) {
+		list_del_init(&rq->queuelist);
+		blk_mq_start_request(rq);
 	}
-	return req;
+
+	return NULL;
 }
 
 static void ace_fsm_dostate(struct ace_device *ace)
@@ -499,11 +509,11 @@ static void ace_fsm_dostate(struct ace_device *ace)
 
 		/* Drop all in-flight and pending requests */
 		if (ace->req) {
-			__blk_end_request_all(ace->req, BLK_STS_IOERR);
+			blk_mq_end_request(ace->req, BLK_STS_IOERR);
 			ace->req = NULL;
 		}
-		while ((req = blk_fetch_request(ace->queue)) != NULL)
-			__blk_end_request_all(req, BLK_STS_IOERR);
+		while ((req = ace_get_next_request(ace->queue)) != NULL)
+			blk_mq_end_request(req, BLK_STS_IOERR);
 
 		/* Drop back to IDLE state and notify waiters */
 		ace->fsm_state = ACE_FSM_STATE_IDLE;
@@ -517,7 +527,7 @@ static void ace_fsm_dostate(struct ace_device *ace)
 	switch (ace->fsm_state) {
 	case ACE_FSM_STATE_IDLE:
 		/* See if there is anything to do */
-		if (ace->id_req_count || ace_get_next_request(ace->queue)) {
+		if (ace->id_req_count || ace_has_next_request(ace->queue)) {
 			ace->fsm_iter_num++;
 			ace->fsm_state = ACE_FSM_STATE_REQ_LOCK;
 			mod_timer(&ace->stall_timer, jiffies + HZ);
@@ -651,7 +661,6 @@ static void ace_fsm_dostate(struct ace_device *ace)
 			ace->fsm_state = ACE_FSM_STATE_IDLE;
 			break;
 		}
-		blk_start_request(req);
 
 		/* Okay, it's a data request, set it up for transfer */
 		dev_dbg(ace->dev,
@@ -728,7 +737,8 @@ static void ace_fsm_dostate(struct ace_device *ace)
 		}
 
 		/* bio finished; is there another one? */
-		if (__blk_end_request_cur(ace->req, BLK_STS_OK)) {
+		if (blk_update_request(ace->req, BLK_STS_OK,
+		    blk_rq_cur_bytes(ace->req))) {
 			/* dev_dbg(ace->dev, "next block; h=%u c=%u\n",
 			 *      blk_rq_sectors(ace->req),
 			 *      blk_rq_cur_sectors(ace->req));
@@ -854,17 +864,23 @@ static irqreturn_t ace_interrupt(int irq, void *dev_id)
 /* ---------------------------------------------------------------------
  * Block ops
  */
-static void ace_request(struct request_queue * q)
+static blk_status_t ace_queue_rq(struct blk_mq_hw_ctx *hctx,
+				 const struct blk_mq_queue_data *bd)
 {
-	struct request *req;
-	struct ace_device *ace;
+	struct ace_device *ace = hctx->queue->queuedata;
+	struct request *req = bd->rq;
 
-	req = ace_get_next_request(q);
-
-	if (req) {
-		ace = req->rq_disk->private_data;
-		tasklet_schedule(&ace->fsm_tasklet);
+	if (blk_rq_is_passthrough(req)) {
+		blk_mq_start_request(req);
+		return BLK_STS_IOERR;
 	}
+
+	spin_lock_irq(&ace->lock);
+	list_add_tail(&req->queuelist, &ace->rq_list);
+	spin_unlock_irq(&ace->lock);
+
+	tasklet_schedule(&ace->fsm_tasklet);
+	return BLK_STS_OK;
 }
 
 static unsigned int ace_check_events(struct gendisk *gd, unsigned int clearing)
@@ -957,11 +973,16 @@ static const struct block_device_operations ace_fops = {
 	.getgeo = ace_getgeo,
 };
 
+static const struct blk_mq_ops ace_mq_ops = {
+	.queue_rq	= ace_queue_rq,
+};
+
 /* --------------------------------------------------------------------
  * SystemACE device setup/teardown code
  */
 static int ace_setup(struct ace_device *ace)
 {
+	struct blk_mq_tag_set *set;
 	u16 version;
 	u16 val;
 	int rc;
@@ -972,6 +993,7 @@ static int ace_setup(struct ace_device *ace)
 
 	spin_lock_init(&ace->lock);
 	init_completion(&ace->id_completion);
+	INIT_LIST_HEAD(&ace->rq_list);
 
 	/*
 	 * Map the device
@@ -989,9 +1011,25 @@ static int ace_setup(struct ace_device *ace)
 	/*
 	 * Initialize the request queue
 	 */
-	ace->queue = blk_init_queue(ace_request, &ace->lock);
-	if (ace->queue == NULL)
+	set = &ace->tag_set;
+	set->ops = &ace_mq_ops;
+	set->nr_hw_queues = 1;
+	set->queue_depth = 2;
+	set->numa_node = NUMA_NO_NODE;
+	set->flags = BLK_MQ_F_SHOULD_MERGE;
+	rc = blk_mq_alloc_tag_set(set);
+	if (rc)
 		goto err_blk_initq;
+
+	ace->queue = blk_mq_init_queue(set);
+	if (IS_ERR(ace->queue)) {
+		rc = PTR_ERR(ace->queue);
+		ace->queue = NULL;
+		blk_mq_free_tag_set(&ace->tag_set);
+		goto err_blk_initq;
+	}
+	ace->queue->queuedata = ace;
+
 	blk_queue_logical_block_size(ace->queue, 512);
 	blk_queue_bounce_limit(ace->queue, BLK_BOUNCE_HIGH);
 
@@ -1065,6 +1103,7 @@ static int ace_setup(struct ace_device *ace)
 err_read:
 	put_disk(ace->gd);
 err_alloc_disk:
+	blk_mq_free_tag_set(&ace->tag_set);
 	blk_cleanup_queue(ace->queue);
 err_blk_initq:
 	iounmap(ace->baseaddr);
@@ -1081,8 +1120,10 @@ static void ace_teardown(struct ace_device *ace)
 		put_disk(ace->gd);
 	}
 
-	if (ace->queue)
+	if (ace->queue) {
+		blk_mq_free_tag_set(&ace->tag_set);
 		blk_cleanup_queue(ace->queue);
+	}
 
 	tasklet_kill(&ace->fsm_tasklet);
 
-- 
2.17.1