Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block

* 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block: (43 commits)
  block: ensure that completion error gets properly traced
  blktrace: add missing probe argument to block_bio_complete
  block cfq: don't use atomic_t for cfq_group
  block cfq: don't use atomic_t for cfq_queue
  block: trace event block fix unassigned field
  block: add internal hd part table references
  block: fix accounting bug on cross partition merges
  kref: add kref_test_and_get
  bio-integrity: mark kintegrityd_wq highpri and CPU intensive
  block: make kblockd_workqueue smarter
  Revert "sd: implement sd_check_events()"
  block: Clean up exit_io_context() source code.
  Fix compile warnings due to missing removal of a 'ret' variable
  fs/block: type signature of major_to_index(int) to major_to_index(unsigned)
  block: convert !IS_ERR(p) && p to !IS_ERR_NOR_NULL(p)
  cfq-iosched: don't check cfqg in choose_service_tree()
  fs/splice: Pull buf->ops->confirm() from splice_from_pipe actors
  cdrom: export cdrom_check_events()
  sd: implement sd_check_events()
  sr: implement sr_check_events()
  ...

1 files changed, 29 insertions, 11 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 4ce953f1b390..2f4002f79a24 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -33,7 +33,7 @@
 
 #include "blk.h"
 
-EXPORT_TRACEPOINT_SYMBOL_GPL(block_remap);
+EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
 
@@ -64,13 +64,27 @@ 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));
+                if (!hd_struct_try_get(part)) {
+                        /*
+                         * The partition is already being removed,
+                         * the request will be accounted on the disk only
+                         *
+                         * We take a reference on disk->part0 although that
+                         * partition will never be deleted, so we can treat
+                         * it as any other partition.
+                         */
+                        part = &rq->rq_disk->part0;
+                        hd_struct_get(part);
+                }
                 part_round_stats(cpu, part);
                 part_inc_in_flight(part, rw);
+                rq->part = part;
         }
 
         part_stat_unlock();
@@ -128,6 +142,7 @@ 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);
 
@@ -1329,9 +1344,9 @@ static inline void blk_partition_remap(struct bio *bio)
                 bio->bi_sector += p->start_sect;
                 bio->bi_bdev = bdev->bd_contains;
 
-                trace_block_remap(bdev_get_queue(bio->bi_bdev), bio,
-                                    bdev->bd_dev,
-                                    bio->bi_sector - p->start_sect);
+                trace_block_bio_remap(bdev_get_queue(bio->bi_bdev), bio,
+                                      bdev->bd_dev,
+                                      bio->bi_sector - p->start_sect);
         }
 }
 
@@ -1500,7 +1515,7 @@ static inline void __generic_make_request(struct bio *bio)
                         goto end_io;
 
                 if (old_sector != -1)
-                        trace_block_remap(q, bio, old_dev, old_sector);
+                        trace_block_bio_remap(q, bio, old_dev, old_sector);
 
                 old_sector = bio->bi_sector;
                 old_dev = bio->bi_bdev->bd_dev;
@@ -1776,7 +1791,7 @@ 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();
         }
@@ -1796,13 +1811,14 @@ 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);
                 part_round_stats(cpu, part);
                 part_dec_in_flight(part, rw);
 
+                hd_struct_put(part);
                 part_stat_unlock();
         }
 }
@@ -2606,7 +2622,9 @@ int __init blk_dev_init(void)
         BUILD_BUG_ON(__REQ_NR_BITS > 8 *
                         sizeof(((struct request *)0)->cmd_flags));
 
-        kblockd_workqueue = create_workqueue("kblockd");
+        /* used for unplugging and affects IO latency/throughput - HIGHPRI */
+        kblockd_workqueue = alloc_workqueue("kblockd",
+                                            WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
         if (!kblockd_workqueue)
                 panic("Failed to create kblockd\n");