diff options
author | Tejun Heo <tj@kernel.org> | 2012-06-04 10:02:29 +0200 |
---|---|---|
committer | Jens Axboe <axboe@kernel.dk> | 2012-06-04 10:02:29 +0200 |
commit | ffea73fc723a12fdde4c9fb3fcce5d154d1104a1 (patch) | |
tree | 45fbb5b7451940383a1773055bbae9a910913447 | |
parent | fd7949564ced88385ca7758a4c1f47c274233dd5 (diff) | |
download | linux-stable-ffea73fc723a12fdde4c9fb3fcce5d154d1104a1.tar.gz linux-stable-ffea73fc723a12fdde4c9fb3fcce5d154d1104a1.tar.bz2 linux-stable-ffea73fc723a12fdde4c9fb3fcce5d154d1104a1.zip |
block: blkcg_policy_cfq shouldn't be used if !CONFIG_CFQ_GROUP_IOSCHED
cfq may be built w/ or w/o blkcg support depending on
CONFIG_CFQ_CGROUP_IOSCHED. If blkcg support is disabled, most of
related code is ifdef'd out but some part is left dangling -
blkcg_policy_cfq is left zero-filled and blkcg_policy_[un]register()
calls are made on it.
Feeding zero filled policy to blkcg_policy_register() is incorrect and
triggers the following WARN_ON() if CONFIG_BLK_CGROUP &&
!CONFIG_CFQ_GROUP_IOSCHED.
------------[ cut here ]------------
WARNING: at block/blk-cgroup.c:867
Modules linked in:
Modules linked in:
CPU: 3 Not tainted 3.4.0-09547-gfb21aff #1
Process swapper/0 (pid: 1, task: 000000003ff80000, ksp: 000000003ff7f8b8)
Krnl PSW : 0704100180000000 00000000003d76ca (blkcg_policy_register+0xca/0xe0)
R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:1 PM:0 EA:3
Krnl GPRS: 0000000000000000 00000000014b85ec 00000000014b85b0 0000000000000000
000000000096fb60 0000000000000000 00000000009a8e78 0000000000000048
000000000099c070 0000000000b6f000 0000000000000000 000000000099c0b8
00000000014b85b0 0000000000667580 000000003ff7fd98 000000003ff7fd70
Krnl Code: 00000000003d76be: a7280001 lhi %r2,1
00000000003d76c2: a7f4ffdf brc 15,3d7680
#00000000003d76c6: a7f40001 brc 15,3d76c8
>00000000003d76ca: a7c8ffea lhi %r12,-22
00000000003d76ce: a7f4ffce brc 15,3d766a
00000000003d76d2: a7f40001 brc 15,3d76d4
00000000003d76d6: a7c80000 lhi %r12,0
00000000003d76da: a7f4ffc2 brc 15,3d765e
Call Trace:
([<0000000000b6f000>] initcall_debug+0x0/0x4)
[<0000000000989e8a>] cfq_init+0x62/0xd4
[<00000000001000ba>] do_one_initcall+0x3a/0x170
[<000000000096fb60>] kernel_init+0x214/0x2bc
[<0000000000623202>] kernel_thread_starter+0x6/0xc
[<00000000006231fc>] kernel_thread_starter+0x0/0xc
no locks held by swapper/0/1.
Last Breaking-Event-Address:
[<00000000003d76c6>] blkcg_policy_register+0xc6/0xe0
---[ end trace b8ef4903fcbf9dd3 ]---
This patch fixes the problem by ensuring all blkcg support code is
inside CONFIG_CFQ_GROUP_IOSCHED.
* blkcg_policy_cfq declaration and blkg_to_cfqg() definition are moved
inside the first CONFIG_CFQ_GROUP_IOSCHED block. __maybe_unused is
dropped from blkcg_policy_cfq decl.
* blkcg_deactivate_poilcy() invocation is moved inside ifdef. This
also makes the activation logic match cfq_init_queue().
* All blkcg_policy_[un]register() invocations are moved inside ifdef.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
LKML-Reference: <20120601112954.GC3535@osiris.boeblingen.de.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r-- | block/cfq-iosched.c | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index ae5113d3ebae..fb52df9744f5 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -17,8 +17,6 @@ #include "blk.h" #include "blk-cgroup.h" -static struct blkcg_policy blkcg_policy_cfq __maybe_unused; - /* * tunables */ @@ -418,11 +416,6 @@ static inline struct cfq_group *pd_to_cfqg(struct blkg_policy_data *pd) return pd ? container_of(pd, struct cfq_group, pd) : NULL; } -static inline struct cfq_group *blkg_to_cfqg(struct blkcg_gq *blkg) -{ - return pd_to_cfqg(blkg_to_pd(blkg, &blkcg_policy_cfq)); -} - static inline struct blkcg_gq *cfqg_to_blkg(struct cfq_group *cfqg) { return pd_to_blkg(&cfqg->pd); @@ -572,6 +565,13 @@ static inline void cfqg_stats_update_avg_queue_size(struct cfq_group *cfqg) { } #ifdef CONFIG_CFQ_GROUP_IOSCHED +static struct blkcg_policy blkcg_policy_cfq; + +static inline struct cfq_group *blkg_to_cfqg(struct blkcg_gq *blkg) +{ + return pd_to_cfqg(blkg_to_pd(blkg, &blkcg_policy_cfq)); +} + static inline void cfqg_get(struct cfq_group *cfqg) { return blkg_get(cfqg_to_blkg(cfqg)); @@ -3951,10 +3951,11 @@ static void cfq_exit_queue(struct elevator_queue *e) cfq_shutdown_timer_wq(cfqd); -#ifndef CONFIG_CFQ_GROUP_IOSCHED +#ifdef CONFIG_CFQ_GROUP_IOSCHED + blkcg_deactivate_policy(q, &blkcg_policy_cfq); +#else kfree(cfqd->root_group); #endif - blkcg_deactivate_policy(q, &blkcg_policy_cfq); kfree(cfqd); } @@ -4194,13 +4195,13 @@ static int __init cfq_init(void) #ifdef CONFIG_CFQ_GROUP_IOSCHED if (!cfq_group_idle) cfq_group_idle = 1; -#else - cfq_group_idle = 0; -#endif ret = blkcg_policy_register(&blkcg_policy_cfq); if (ret) return ret; +#else + cfq_group_idle = 0; +#endif ret = -ENOMEM; cfq_pool = KMEM_CACHE(cfq_queue, 0); @@ -4216,13 +4217,17 @@ static int __init cfq_init(void) err_free_pool: kmem_cache_destroy(cfq_pool); err_pol_unreg: +#ifdef CONFIG_CFQ_GROUP_IOSCHED blkcg_policy_unregister(&blkcg_policy_cfq); +#endif return ret; } static void __exit cfq_exit(void) { +#ifdef CONFIG_CFQ_GROUP_IOSCHED blkcg_policy_unregister(&blkcg_policy_cfq); +#endif elv_unregister(&iosched_cfq); kmem_cache_destroy(cfq_pool); } |