block: fix accounting bug on cross partition merges

[net-next-2.6.git] / block / blk-core.c

diff --git a/block/blk-core.c b/block/blk-core.c
index 797d5095eb83fa5cada4be1712858fe6dc391145..ddc68332d65568a0438b36007e4ff868ca55cf84 100644 (file)
--- 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);