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Commit 42ec57a8 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

block: misc ioc cleanups 



* int return from put_io_context() wasn't used by anybody.  Make it
  return void like other put functions and docbook-fy the function
  comment.

* Reorder dummy declarations for !CONFIG_BLOCK case a bit.

* Make alloc_ioc_context() use __GFP_ZERO allocation, take init out of
  if block and drop 0'ing.

* Docbook-fy current_io_context() comment.

This patch doesn't introduce any functional change.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a73f730d

block/blk-ioc.c

+36 −36
Original line number Diff line number Diff line
@@ -27,26 +27,28 @@ static void cfq_dtor(struct io_context *ioc) 
	}

}



/*

 * IO Context helper functions. put_io_context() returns 1 if there are no

 * more users of this io context, 0 otherwise.

/**

 * put_io_context - put a reference of io_context

 * @ioc: io_context to put

 *

 * Decrement reference count of @ioc and release it if the count reaches

 * zero.

 */

int put_io_context(struct io_context *ioc)

void put_io_context(struct io_context *ioc)

{

	if (ioc == NULL)

		return 1;

		return;



	BUG_ON(atomic_long_read(&ioc->refcount) <= 0);



	BUG_ON(atomic_long_read(&ioc->refcount) == 0);

	if (!atomic_long_dec_and_test(&ioc->refcount))

		return;



	if (atomic_long_dec_and_test(&ioc->refcount)) {

	rcu_read_lock();

	cfq_dtor(ioc);

	rcu_read_unlock();



	kmem_cache_free(iocontext_cachep, ioc);

		return 1;

	}

	return 0;

}

EXPORT_SYMBOL(put_io_context);
@@ -84,33 +86,31 @@ struct io_context *alloc_io_context(gfp_t gfp_flags, int node) 
{

	struct io_context *ioc;



	ioc = kmem_cache_alloc_node(iocontext_cachep, gfp_flags, node);

	if (ioc) {

	ioc = kmem_cache_alloc_node(iocontext_cachep, gfp_flags | __GFP_ZERO,

				    node);

	if (unlikely(!ioc))

		return NULL;



	/* initialize */

	atomic_long_set(&ioc->refcount, 1);

	atomic_set(&ioc->nr_tasks, 1);

	spin_lock_init(&ioc->lock);

		ioc->ioprio_changed = 0;

		ioc->ioprio = 0;

		ioc->last_waited = 0; /* doesn't matter... */

		ioc->nr_batch_requests = 0; /* because this is 0 */

	INIT_RADIX_TREE(&ioc->radix_root, GFP_ATOMIC | __GFP_HIGH);

	INIT_HLIST_HEAD(&ioc->cic_list);

		ioc->ioc_data = NULL;

#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)

		ioc->cgroup_changed = 0;

#endif

	}



	return ioc;

}



/*

 * If the current task has no IO context then create one and initialise it.

 * Otherwise, return its existing IO context.

/**

 * current_io_context - get io_context of %current

 * @gfp_flags: allocation flags, used if allocation is necessary

 * @node: allocation node, used if allocation is necessary

 *

 * This returned IO context doesn't have a specifically elevated refcount,

 * but since the current task itself holds a reference, the context can be

 * used in general code, so long as it stays within `current` context.

 * Return io_context of %current.  If it doesn't exist, it is created with

 * @gfp_flags and @node.  The returned io_context does NOT have its

 * reference count incremented.  Because io_context is exited only on task

 * exit, %current can be sure that the returned io_context is valid and

 * alive as long as it is executing.

 */

struct io_context *current_io_context(gfp_t gfp_flags, int node)

{

include/linux/iocontext.h

+3 −9
Original line number Diff line number Diff line
@@ -76,20 +76,14 @@ static inline struct io_context *ioc_task_link(struct io_context *ioc) 


struct task_struct;

#ifdef CONFIG_BLOCK

int put_io_context(struct io_context *ioc);

void put_io_context(struct io_context *ioc);

void exit_io_context(struct task_struct *task);

struct io_context *get_io_context(gfp_t gfp_flags, int node);

struct io_context *alloc_io_context(gfp_t gfp_flags, int node);

#else

static inline void exit_io_context(struct task_struct *task)

{

}



struct io_context;

static inline int put_io_context(struct io_context *ioc)

{

	return 1;

}

static inline void put_io_context(struct io_context *ioc) { }

static inline void exit_io_context(struct task_struct *task) { }

#endif



#endif