Revert "block: fix accounting bug on cross partition merges"

This reverts commit 7681bfee.

Conflicts:

	include/linux/genhd.h

It has numerous issues with the cleanup path and non-elevator
devices. Revert it for now so we can come up with a clean
version without rushing things.
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

block/blk-core.c

@@ -64,15 +64,13 @@ static void drive_stat_acct(struct request *rq, int new_io)
 		return;
 
 	cpu = part_stat_lock();
+	part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
 
-	if (!new_io) {
-		part = rq->part;
+	if (!new_io)
 		part_stat_inc(cpu, part, merges[rw]);
-	} else {
-		part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
+	else {
 		part_round_stats(cpu, part);
 		part_inc_in_flight(part, rw);
-		rq->part = part;
 	}
 
 	part_stat_unlock();
@@ -130,7 +128,6 @@ void blk_rq_init(struct request_queue *q, struct request *rq)
 	rq->ref_count = 1;
 	rq->start_time = jiffies;
 	set_start_time_ns(rq);
-	rq->part = NULL;
 }
 EXPORT_SYMBOL(blk_rq_init);
 
@@ -805,16 +802,11 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
 	rl->starved[is_sync] = 0;
 
 	priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
-	if (priv) {
+	if (priv)
 		rl->elvpriv++;
 
-		/*
-		 * Don't do stats for non-priv requests
-		 */
-		if (blk_queue_io_stat(q))
-			rw_flags |= REQ_IO_STAT;
-	}
-
+	if (blk_queue_io_stat(q))
+		rw_flags |= REQ_IO_STAT;
 	spin_unlock_irq(q->queue_lock);
 
 	rq = blk_alloc_request(q, rw_flags, priv, gfp_mask);
@@ -1791,7 +1783,7 @@ static void blk_account_io_completion(struct request *req, unsigned int bytes)
 		int cpu;
 
 		cpu = part_stat_lock();
-		part = req->part;
+		part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
 		part_stat_add(cpu, part, sectors[rw], bytes >> 9);
 		part_stat_unlock();
 	}
@@ -1811,7 +1803,7 @@ static void blk_account_io_done(struct request *req)
 		int cpu;
 
 		cpu = part_stat_lock();
-		part = req->part;
+		part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
 
 		part_stat_inc(cpu, part, ios[rw]);
 		part_stat_add(cpu, part, ticks[rw], duration);

block/blk-merge.c

@@ -351,7 +351,7 @@ static void blk_account_io_merge(struct request *req)
 		int cpu;
 
 		cpu = part_stat_lock();
-		part = req->part;
+		part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
 
 		part_round_stats(cpu, part);
 		part_dec_in_flight(part, rq_data_dir(req));

block/blk.h

@@ -116,6 +116,10 @@ void blk_queue_congestion_threshold(struct request_queue *q);
 
 int blk_dev_init(void);
 
+void elv_quiesce_start(struct request_queue *q);
+void elv_quiesce_end(struct request_queue *q);
+
+
 /*
  * Return the threshold (number of used requests) at which the queue is
  * considered to be congested.  It include a little hysteresis to keep the

block/genhd.c

@@ -929,15 +929,8 @@ static void disk_free_ptbl_rcu_cb(struct rcu_head *head)
 {
 	struct disk_part_tbl *ptbl =
 		container_of(head, struct disk_part_tbl, rcu_head);
-	struct gendisk *disk = ptbl->disk;
-	struct request_queue *q = disk->queue;
-	unsigned long flags;
 
 	kfree(ptbl);
-
-	spin_lock_irqsave(q->queue_lock, flags);
-	elv_quiesce_end(q);
-	spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
 /**
@@ -955,17 +948,11 @@ static void disk_replace_part_tbl(struct gendisk *disk,
 				  struct disk_part_tbl *new_ptbl)
 {
 	struct disk_part_tbl *old_ptbl = disk->part_tbl;
-	struct request_queue *q = disk->queue;
 
 	rcu_assign_pointer(disk->part_tbl, new_ptbl);
 
 	if (old_ptbl) {
 		rcu_assign_pointer(old_ptbl->last_lookup, NULL);
-
-		spin_lock_irq(q->queue_lock);
-		elv_quiesce_start(q);
-		spin_unlock_irq(q->queue_lock);
-
 		call_rcu(&old_ptbl->rcu_head, disk_free_ptbl_rcu_cb);
 	}
 }
@@ -1006,7 +993,6 @@ int disk_expand_part_tbl(struct gendisk *disk, int partno)
 		return -ENOMEM;
 
 	new_ptbl->len = target;
-	new_ptbl->disk = disk;
 
 	for (i = 0; i < len; i++)
 		rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]);

fs/partitions/check.c

@@ -365,25 +365,17 @@ struct device_type part_type = {
 static void delete_partition_rcu_cb(struct rcu_head *head)
 {
 	struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
-	struct gendisk *disk = part_to_disk(part);
-	struct request_queue *q = disk->queue;
-	unsigned long flags;
 
 	part->start_sect = 0;
 	part->nr_sects = 0;
 	part_stat_set_all(part, 0);
 	put_device(part_to_dev(part));
-
-	spin_lock_irqsave(q->queue_lock, flags);
-	elv_quiesce_end(q);
-	spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
 void delete_partition(struct gendisk *disk, int partno)
 {
 	struct disk_part_tbl *ptbl = disk->part_tbl;
 	struct hd_struct *part;
-	struct request_queue *q = disk->queue;
 
 	if (partno >= ptbl->len)
 		return;
@@ -398,10 +390,6 @@ void delete_partition(struct gendisk *disk, int partno)
 	kobject_put(part->holder_dir);
 	device_del(part_to_dev(part));
 
-	spin_lock_irq(q->queue_lock);
-	elv_quiesce_start(q);
-	spin_unlock_irq(q->queue_lock);
-
 	call_rcu(&part->rcu_head, delete_partition_rcu_cb);
 }
 

include/linux/blkdev.h

@@ -115,7 +115,6 @@ struct request {
 	void *elevator_private3;
 
 	struct gendisk *rq_disk;
-	struct hd_struct *part;
 	unsigned long start_time;
 #ifdef CONFIG_BLK_CGROUP
 	unsigned long long start_time_ns;

include/linux/elevator.h

@@ -122,8 +122,6 @@ extern void elv_completed_request(struct request_queue *, struct request *);
 extern int elv_set_request(struct request_queue *, struct request *, gfp_t);
 extern void elv_put_request(struct request_queue *, struct request *);
 extern void elv_drain_elevator(struct request_queue *);
-extern void elv_quiesce_start(struct request_queue *);
-extern void elv_quiesce_end(struct request_queue *);
 
 /*
  * io scheduler registration

include/linux/genhd.h

@@ -140,7 +140,6 @@ struct disk_part_tbl {
 	struct rcu_head rcu_head;
 	int len;
 	struct hd_struct __rcu *last_lookup;
-	struct gendisk *disk;
 	struct hd_struct __rcu *part[];
 };