paride: convert pd to blk-mq

Tested-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/paride/pd.c

@@ -151,7 +151,7 @@ enum {D_PRT, D_PRO, D_UNI, D_MOD, D_GEO, D_SBY, D_DLY, D_SLV};
 #include <linux/delay.h>
 #include <linux/hdreg.h>
 #include <linux/cdrom.h>	/* for the eject ioctl */
-#include <linux/blkdev.h>
+#include <linux/blk-mq.h>
 #include <linux/blkpg.h>
 #include <linux/kernel.h>
 #include <linux/mutex.h>
@@ -236,6 +236,8 @@ struct pd_unit {
 	int alt_geom;
 	char name[PD_NAMELEN];	/* pda, pdb, etc ... */
 	struct gendisk *gd;
+	struct blk_mq_tag_set tag_set;
+	struct list_head rq_list;
 };
 
 static struct pd_unit pd[PD_UNITS];
@@ -399,9 +401,17 @@ static int set_next_request(void)
 		if (++pd_queue == PD_UNITS)
 			pd_queue = 0;
 		if (q) {
-			pd_req = blk_fetch_request(q);
-			if (pd_req)
-				break;
+			struct pd_unit *disk = q->queuedata;
+
+			if (list_empty(&disk->rq_list))
+				continue;
+
+			pd_req = list_first_entry(&disk->rq_list,
+							struct request,
+							queuelist);
+			list_del_init(&pd_req->queuelist);
+			blk_mq_start_request(pd_req);
+			break;
 		}
 	} while (pd_queue != old_pos);
 
@@ -412,7 +422,6 @@ static void run_fsm(void)
 {
 	while (1) {
 		enum action res;
-		unsigned long saved_flags;
 		int stop = 0;
 
 		if (!phase) {
@@ -433,19 +442,24 @@ static void run_fsm(void)
 		}
 
 		switch(res = phase()) {
-			case Ok: case Fail:
+			case Ok: case Fail: {
+				blk_status_t err;
+
+				err = res == Ok ? 0 : BLK_STS_IOERR;
 				pi_disconnect(pi_current);
 				pd_claimed = 0;
 				phase = NULL;
-				spin_lock_irqsave(&pd_lock, saved_flags);
-				if (!__blk_end_request_cur(pd_req,
-						res == Ok ? 0 : BLK_STS_IOERR)) {
-					if (!set_next_request())
-						stop = 1;
+				spin_lock_irq(&pd_lock);
+				if (!blk_update_request(pd_req, err,
+						blk_rq_cur_bytes(pd_req))) {
+					__blk_mq_end_request(pd_req, err);
+					pd_req = NULL;
+					stop = !set_next_request();
 				}
-				spin_unlock_irqrestore(&pd_lock, saved_flags);
+				spin_unlock_irq(&pd_lock);
 				if (stop)
 					return;
+				}
 				/* fall through */
 			case Hold:
 				schedule_fsm();
@@ -505,11 +519,17 @@ static int pd_next_buf(void)
 	if (pd_count)
 		return 0;
 	spin_lock_irqsave(&pd_lock, saved_flags);
-	__blk_end_request_cur(pd_req, 0);
-	pd_count = blk_rq_cur_sectors(pd_req);
-	pd_buf = bio_data(pd_req->bio);
+	if (!blk_update_request(pd_req, 0, blk_rq_cur_bytes(pd_req))) {
+		__blk_mq_end_request(pd_req, 0);
+		pd_req = NULL;
+		pd_count = 0;
+		pd_buf = NULL;
+	} else {
+		pd_count = blk_rq_cur_sectors(pd_req);
+		pd_buf = bio_data(pd_req->bio);
+	}
 	spin_unlock_irqrestore(&pd_lock, saved_flags);
-	return 0;
+	return !pd_count;
 }
 
 static unsigned long pd_timeout;
@@ -726,15 +746,21 @@ static enum action pd_identify(struct pd_unit *disk)
 
 /* end of io request engine */
 
-static void do_pd_request(struct request_queue * q)
+static blk_status_t pd_queue_rq(struct blk_mq_hw_ctx *hctx,
+				const struct blk_mq_queue_data *bd)
 {
-	if (pd_req)
-		return;
-	pd_req = blk_fetch_request(q);
-	if (!pd_req)
-		return;
+	struct pd_unit *disk = hctx->queue->queuedata;
+
+	spin_lock_irq(&pd_lock);
+	if (!pd_req) {
+		pd_req = bd->rq;
+		blk_mq_start_request(pd_req);
+	} else
+		list_add_tail(&bd->rq->queuelist, &disk->rq_list);
+	spin_unlock_irq(&pd_lock);
 
-	schedule_fsm();
+	run_fsm();
+	return BLK_STS_OK;
 }
 
 static int pd_special_command(struct pd_unit *disk,
@@ -847,23 +873,33 @@ static const struct block_device_operations pd_fops = {
 
 /* probing */
 
+static const struct blk_mq_ops pd_mq_ops = {
+	.queue_rq	= pd_queue_rq,
+};
+
 static void pd_probe_drive(struct pd_unit *disk)
 {
-	struct gendisk *p = alloc_disk(1 << PD_BITS);
+	struct gendisk *p;
+
+	p = alloc_disk(1 << PD_BITS);
 	if (!p)
 		return;
+
 	strcpy(p->disk_name, disk->name);
 	p->fops = &pd_fops;
 	p->major = major;
 	p->first_minor = (disk - pd) << PD_BITS;
 	disk->gd = p;
 	p->private_data = disk;
-	p->queue = blk_init_queue(do_pd_request, &pd_lock);
-	if (!p->queue) {
-		disk->gd = NULL;
-		put_disk(p);
+
+	p->queue = blk_mq_init_sq_queue(&disk->tag_set, &pd_mq_ops, 2,
+				BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING);
+	if (IS_ERR(p->queue)) {
+		p->queue = NULL;
 		return;
 	}
+
+	p->queue->queuedata = disk;
 	blk_queue_max_hw_sectors(p->queue, cluster);
 	blk_queue_bounce_limit(p->queue, BLK_BOUNCE_HIGH);
 
@@ -895,6 +931,7 @@ static int pd_detect(void)
 		disk->standby = parm[D_SBY];
 		if (parm[D_PRT])
 			pd_drive_count++;
+		INIT_LIST_HEAD(&disk->rq_list);
 	}
 
 	par_drv = pi_register_driver(name);
@@ -972,6 +1009,7 @@ static void __exit pd_exit(void)
 			disk->gd = NULL;
 			del_gendisk(p);
 			blk_cleanup_queue(p->queue);
+			blk_mq_free_tag_set(&disk->tag_set);
 			put_disk(p);
 			pi_release(disk->pi);
 		}