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Commit 24acfc34 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

block: interface update for ioc/icq creation functions 



Make the following interface updates to prepare for future ioc related
changes.

* create_io_context() returning ioc only works for %current because it
  doesn't increment ref on the ioc.  Drop @task parameter from it and
  always assume %current.

* Make create_io_context_slowpath() return 0 or -errno and rename it
  to create_task_io_context().

* Make ioc_create_icq() take @ioc as parameter instead of assuming
  that of %current.  The caller, get_request(), is updated to create
  ioc explicitly and then pass it into ioc_create_icq().

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent b679281a

block/blk-core.c

+5 −3
Original line number Diff line number Diff line
@@ -855,7 +855,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags, 
			 */

			if (!ioc && !retried) {

				spin_unlock_irq(q->queue_lock);

				create_io_context(current, gfp_mask, q->node);

				create_io_context(gfp_mask, q->node);

				spin_lock_irq(q->queue_lock);

				retried = true;

				goto retry;
@@ -919,7 +919,9 @@ static struct request *get_request(struct request_queue *q, int rw_flags, 


	/* create icq if missing */

	if ((rw_flags & REQ_ELVPRIV) && unlikely(et->icq_cache && !icq)) {

		icq = ioc_create_icq(q, gfp_mask);

		ioc = create_io_context(gfp_mask, q->node);

		if (ioc)

			icq = ioc_create_icq(ioc, q, gfp_mask);

		if (!icq)

			goto fail_alloc;

	}
@@ -1005,7 +1007,7 @@ static struct request *get_request_wait(struct request_queue *q, int rw_flags, 
		 * up to a big batch of them for a small period time.

		 * See ioc_batching, ioc_set_batching

		 */

		create_io_context(current, GFP_NOIO, q->node);

		create_io_context(GFP_NOIO, q->node);

		ioc_set_batching(q, current->io_context);



		spin_lock_irq(q->queue_lock);

block/blk-ioc.c

+10 −12
Original line number Diff line number Diff line
@@ -212,15 +212,14 @@ void ioc_clear_queue(struct request_queue *q) 
	}

}



void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_flags,

				int node)

int create_task_io_context(struct task_struct *task, gfp_t gfp_flags, int node)

{

	struct io_context *ioc;



	ioc = kmem_cache_alloc_node(iocontext_cachep, gfp_flags | __GFP_ZERO,

				    node);

	if (unlikely(!ioc))

		return;

		return -ENOMEM;



	/* initialize */

	atomic_long_set(&ioc->refcount, 1);
@@ -244,6 +243,8 @@ void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_flags, 
	else

		kmem_cache_free(iocontext_cachep, ioc);

	task_unlock(task);



	return 0;

}



/**
@@ -275,7 +276,7 @@ struct io_context *get_task_io_context(struct task_struct *task, 
			return ioc;

		}

		task_unlock(task);

	} while (create_io_context(task, gfp_flags, node));

	} while (!create_task_io_context(task, gfp_flags, node));



	return NULL;

}
@@ -319,26 +320,23 @@ EXPORT_SYMBOL(ioc_lookup_icq); 


/**

 * ioc_create_icq - create and link io_cq

 * @ioc: io_context of interest

 * @q: request_queue of interest

 * @gfp_mask: allocation mask

 *

 * Make sure io_cq linking %current->io_context and @q exists.  If either

 * io_context and/or icq don't exist, they will be created using @gfp_mask.

 * Make sure io_cq linking @ioc and @q exists.  If icq doesn't exist, they

 * will be created using @gfp_mask.

 *

 * The caller is responsible for ensuring @ioc won't go away and @q is

 * alive and will stay alive until this function returns.

 */

struct io_cq *ioc_create_icq(struct request_queue *q, gfp_t gfp_mask)

struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,

			     gfp_t gfp_mask)

{

	struct elevator_type *et = q->elevator->type;

	struct io_context *ioc;

	struct io_cq *icq;



	/* allocate stuff */

	ioc = create_io_context(current, gfp_mask, q->node);

	if (!ioc)

		return NULL;



	icq = kmem_cache_alloc_node(et->icq_cache, gfp_mask | __GFP_ZERO,

				    q->node);

	if (!icq)

block/blk.h

+11 −13
Original line number Diff line number Diff line
@@ -200,32 +200,30 @@ static inline int blk_do_io_stat(struct request *rq) 
 */

void get_io_context(struct io_context *ioc);

struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);

struct io_cq *ioc_create_icq(struct request_queue *q, gfp_t gfp_mask);

struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,

			     gfp_t gfp_mask);

void ioc_clear_queue(struct request_queue *q);



void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_mask,

				int node);

int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);



/**

 * create_io_context - try to create task->io_context

 * @task: target task

 * @gfp_mask: allocation mask

 * @node: allocation node

 *

 * If @task->io_context is %NULL, allocate a new io_context and install it.

 * Returns the current @task->io_context which may be %NULL if allocation

 * failed.

 * If %current->io_context is %NULL, allocate a new io_context and install

 * it.  Returns the current %current->io_context which may be %NULL if

 * allocation failed.

 *

 * Note that this function can't be called with IRQ disabled because

 * task_lock which protects @task->io_context is IRQ-unsafe.

 * task_lock which protects %current->io_context is IRQ-unsafe.

 */

static inline struct io_context *create_io_context(struct task_struct *task,

						   gfp_t gfp_mask, int node)

static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)

{

	WARN_ON_ONCE(irqs_disabled());

	if (unlikely(!task->io_context))

		create_io_context_slowpath(task, gfp_mask, node);

	return task->io_context;

	if (unlikely(!current->io_context))

		create_task_io_context(current, gfp_mask, node);

	return current->io_context;

}



/*