8 files changed, 47 insertions, 13 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 797d5095eb83..ddc68332d655 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -64,13 +64,15 @@ 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)
+        if (!new_io) {
+                part = rq->part;
                 part_stat_inc(cpu, part, merges[rw]);
-        else {
+        } else {
+                part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
                 part_round_stats(cpu, part);
                 part_inc_in_flight(part, rw);
+                rq->part = part;
         }
 
         part_stat_unlock();
@@ -128,6 +130,7 @@ 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);
 
@@ -804,11 +807,16 @@ 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++;
 
-        if (blk_queue_io_stat(q))
-                rw_flags |= REQ_IO_STAT;
+                /*
+                 * Don't do stats for non-priv requests
+                 */
+                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);
@@ -1777,7 +1785,7 @@ static void blk_account_io_completion(struct request *req, unsigned int bytes)
                 int cpu;
 
                 cpu = part_stat_lock();
-                part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
+                part = req->part;
                 part_stat_add(cpu, part, sectors[rw], bytes >> 9);
                 part_stat_unlock();
         }
@@ -1797,7 +1805,7 @@ static void blk_account_io_done(struct request *req)
                 int cpu;
 
                 cpu = part_stat_lock();
-                part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
+                part = req->part;
 
                 part_stat_inc(cpu, part, ios[rw]);
                 part_stat_add(cpu, part, ticks[rw], duration);
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 6a725461654d..38ff234012a4 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -351,7 +351,7 @@ static void blk_account_io_merge(struct request *req)
                 int cpu;
 
                 cpu = part_stat_lock();
-                part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
+                part = req->part;
 
                 part_round_stats(cpu, part);
                 part_dec_in_flight(part, rq_data_dir(req));
diff --git a/block/blk.h b/block/blk.h
index 6738831ba447..1340cce5721a 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -110,10 +110,6 @@ 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
diff --git a/block/genhd.c b/block/genhd.c
index 7923e720ddf5..8313834596db 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -932,8 +932,15 @@ 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);
 }
 
 /**
@@ -951,11 +958,17 @@ 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);
         }
 }
@@ -996,6 +1009,7 @@ 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]);
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index 6dfbee03ccc6..30f46c2cb9d5 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -365,17 +365,25 @@ 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;
@@ -390,6 +398,10 @@ 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);
 }
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 8f3dd981b973..16f7f1be1acf 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -115,6 +115,7 @@ 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;
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index 2c958f4fce1e..df1ee866d715 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -121,6 +121,8 @@ 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
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 66e26b5a1537..57647ecfc1bd 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -140,6 +140,7 @@ struct disk_part_tbl {
         struct rcu_head rcu_head;
         int len;
         struct hd_struct *last_lookup;
+        struct gendisk *disk;
         struct hd_struct *part[];
 };