[PATCH] deal with rmmod/put_io_context() races (334e94de) · Commits · e / devices / android_kernel_xiaomi_markw

block/as-iosched.c

+14 −1

Original line number	Diff line number	Diff line
		@@ -182,6 +182,9 @@ struct as_rq {

		static kmem_cache_t *arq_pool;

		static atomic_t ioc_count = ATOMIC_INIT(0);
		static struct completion *ioc_gone;

		static void as_move_to_dispatch(struct as_data ad, struct as_rq arq);
		static void as_antic_stop(struct as_data *ad);

		@@ -193,11 +196,14 @@ static void as_antic_stop(struct as_data *ad);
		static void free_as_io_context(struct as_io_context *aic)
		{
		kfree(aic);
		if (atomic_dec_and_test(&ioc_count) && ioc_gone)
		complete(ioc_gone);
		}

		static void as_trim(struct io_context *ioc)
		{
		kfree(ioc->aic);
		if (ioc->aic)
		free_as_io_context(ioc->aic);
		ioc->aic = NULL;
		}

		@@ -226,6 +232,7 @@ static struct as_io_context *alloc_as_io_context(void)
		ret->seek_total = 0;
		ret->seek_samples = 0;
		ret->seek_mean = 0;
		atomic_inc(&ioc_count);
		}

		return ret;
		@@ -1900,7 +1907,13 @@ static int __init as_init(void)

		static void __exit as_exit(void)
		{
		DECLARE_COMPLETION(all_gone);
		elv_unregister(&iosched_as);
		ioc_gone = &all_gone;
		barrier();
		if (atomic_read(&ioc_count))
		complete(ioc_gone);
		synchronize_rcu();
		kmem_cache_destroy(arq_pool);
		}

block/cfq-iosched.c

+16 −0

Original line number	Diff line number	Diff line
		@@ -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();
		}

block/ll_rw_blk.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -3477,10 +3477,12 @@ void put_io_context(struct io_context *ioc)
		BUG_ON(atomic_read(&ioc->refcount) == 0);

		if (atomic_dec_and_test(&ioc->refcount)) {
		rcu_read_lock();
		if (ioc->aic && ioc->aic->dtor)
		ioc->aic->dtor(ioc->aic);
		if (ioc->cic && ioc->cic->dtor)
		ioc->cic->dtor(ioc->cic);
		rcu_read_unlock();

		kmem_cache_free(iocontext_cachep, ioc);
		}