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| author | Al Viro <viro@zeniv.linux.org.uk> | 2006-03-18 15:05:53 -0500 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2006-03-18 18:34:15 -0500 |
| commit | 334e94de9bea353156abd6f2242d3cc4a24562b0 (patch) | |
| tree | ff4a253e9e3bf487be03bf58727a7ea40a34ba87 /block/cfq-iosched.c | |
| parent | e17a9489b4a686bb5e9615e1d375c67619cb99c5 (diff) | |
| download | lwn-334e94de9bea353156abd6f2242d3cc4a24562b0.tar.gz lwn-334e94de9bea353156abd6f2242d3cc4a24562b0.zip | |
[PATCH] deal with rmmod/put_io_context() races
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'block/cfq-iosched.c')
| -rw-r--r-- | block/cfq-iosched.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 7102bafc98b3..3cd985bece3a 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -91,6 +91,9 @@ static kmem_cache_t *crq_pool; static kmem_cache_t *cfq_pool; static kmem_cache_t *cfq_ioc_pool; +static atomic_t ioc_count = ATOMIC_INIT(0); +static struct completion *ioc_gone; + #define CFQ_PRIO_LISTS IOPRIO_BE_NR #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) #define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE) @@ -1202,13 +1205,17 @@ static void cfq_free_io_context(struct cfq_io_context *cic) { struct cfq_io_context *__cic; struct list_head *entry, *next; + int freed = 1; list_for_each_safe(entry, next, &cic->list) { __cic = list_entry(entry, struct cfq_io_context, list); kmem_cache_free(cfq_ioc_pool, __cic); + freed++; } kmem_cache_free(cfq_ioc_pool, cic); + if (atomic_sub_and_test(freed, &ioc_count) && ioc_gone) + complete(ioc_gone); } static void cfq_trim(struct io_context *ioc) @@ -1297,6 +1304,7 @@ cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) cic->dtor = cfq_free_io_context; cic->exit = cfq_exit_io_context; INIT_LIST_HEAD(&cic->queue_list); + atomic_inc(&ioc_count); } return cic; @@ -1501,6 +1509,7 @@ restart: list); read_unlock(&cfq_exit_lock); kmem_cache_free(cfq_ioc_pool, cic); + atomic_dec(&ioc_count); goto restart; } @@ -1523,6 +1532,7 @@ restart: list_del(&__cic->list); read_unlock(&cfq_exit_lock); kmem_cache_free(cfq_ioc_pool, __cic); + atomic_dec(&ioc_count); goto restart; } } @@ -2510,7 +2520,13 @@ static int __init cfq_init(void) static void __exit cfq_exit(void) { + DECLARE_COMPLETION(all_gone); elv_unregister(&iosched_cfq); + ioc_gone = &all_gone; + barrier(); + if (atomic_read(&ioc_count)) + complete(ioc_gone); + synchronize_rcu(); cfq_slab_kill(); } |