Tejun Heo c875f4d025 blkcg: drop unnecessary RCU locking ...

Now that blkg additions / removals are always done under both q and
blkcg locks, the only places RCU locking is necessary are
blkg_lookup[_create]() for lookup w/o blkcg lock.  This patch drops
unncessary RCU locking replacing it with plain blkcg locking as
necessary.

* blkiocg_pre_destroy() already perform proper locking and don't need
  RCU.  Dropped.

* blkio_read_blkg_stats() now uses blkcg->lock instead of RCU read
  lock.  This isn't a hot path.

* Now unnecessary synchronize_rcu() from queue exit paths removed.
  This makes q->nr_blkgs unnecessary.  Dropped.

* RCU annotation on blkg->q removed.

-v2: Vivek pointed out that blkg_lookup_create() still needs to be
     called under rcu_read_lock().  Updated.

-v3: After the update, stats_lock locking in blkio_read_blkg_stats()
     shouldn't be using _irq variant as it otherwise ends up enabling
     irq while blkcg->lock is locked.  Fixed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

2012-03-06 21:27:24 +01:00

..

partitions

separate partition format handling from generic code

2012-01-03 22:54:06 -05:00

blk-cgroup.c

blkcg: drop unnecessary RCU locking

2012-03-06 21:27:24 +01:00

blk-cgroup.h

blkcg: drop unnecessary RCU locking

2012-03-06 21:27:24 +01:00

blk-core.c

blkcg: unify blkg's for blkcg policies

2012-03-06 21:27:23 +01:00

blk-exec.c

block: add missing blk_queue_dead() checks

2011-12-14 00:33:37 +01:00

blk-flush.c

blk-flush: move the queue kick into

2011-10-24 16:24:31 +02:00

blk-integrity.c

block: add export.h to files using EXPORT_SYMBOL/THIS_MODULE macros

2011-10-31 19:31:12 -04:00

blk-ioc.c

block: exit_io_context() should call elevator_exit_icq_fn()

2012-02-15 09:45:53 +01:00

blk-iopoll.c

tree-wide: fix assorted typos all over the place

2009-12-04 15:39:55 +01:00

blk-lib.c

block: fix patch import error in max_discard_sectors check

2011-07-23 20:34:59 +02:00

blk-map.c

block: re-use existing 'reading' variable instead of checking direction again

2011-12-21 15:27:24 +01:00

blk-merge.c

block: separate out blk_rq_merge_ok() and blk_try_merge() from elevator functions

2012-02-08 09:19:38 +01:00

blk-settings.c

block: Introduce blk_set_stacking_limits function

2012-01-11 16:27:11 +01:00

blk-softirq.c

block: Don't check QUEUE_FLAG_SAME_COMP in __blk_complete_request

2011-09-14 09:31:01 +02:00

blk-sysfs.c

blkcg: unify blkg's for blkcg policies

2012-03-06 21:27:23 +01:00

blk-tag.c

block: fix blk_queue_end_tag()

2011-12-29 09:16:28 +01:00

blk-throttle.c

blkcg: drop unnecessary RCU locking

2012-03-06 21:27:24 +01:00

blk-timeout.c

fault-injection: add ability to export fault_attr in arbitrary directory

2011-08-03 14:25:20 -10:00

blk.h

blkcg: add blkcg_{init|drain|exit}_queue()

2012-03-06 21:27:23 +01:00

bsg-lib.c

block: Change module.h -> export.h in bsg-lib.c

2011-10-31 19:31:13 -04:00

bsg.c

bsg: fix sysfs link remove warning

2012-02-08 20:02:03 +01:00

cfq-iosched.c

blkcg: drop unnecessary RCU locking

2012-03-06 21:27:24 +01:00

cfq.h

blkcg: use double locking instead of RCU for blkg synchronization

2012-03-06 21:27:24 +01:00

compat_ioctl.c

block: Add BLKROTATIONAL ioctl

2012-01-11 16:29:31 +01:00

deadline-iosched.c

elevator: make elevator_init_fn() return 0/-errno

2012-03-06 21:27:21 +01:00

elevator.c

blkcg: unify blkg's for blkcg policies

2012-03-06 21:27:23 +01:00

genhd.c

Block: use a freezable workqueue for disk-event polling

2012-03-02 10:51:00 +01:00

ioctl.c

Merge branch 'for-3.3/core' of git://git.kernel.dk/linux-block

2012-01-15 12:24:45 -08:00

Kconfig

move fs/partitions to block/

2012-01-03 22:54:06 -05:00

Kconfig.iosched

blkcg: make CONFIG_BLK_CGROUP bool

2012-03-06 21:27:21 +01:00

Makefile

separate partition format handling from generic code

2012-01-03 22:54:06 -05:00

noop-iosched.c

elevator: make elevator_init_fn() return 0/-errno

2012-03-06 21:27:21 +01:00

partition-generic.c

block: Fix NULL pointer dereference in sd_revalidate_disk

2012-03-02 10:38:33 +01:00

scsi_ioctl.c

block: fail SCSI passthrough ioctls on partition devices

2012-01-14 15:07:24 -08:00