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: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 11 insertions, 13 deletions

diff --git a/block/blk.h b/block/blk.h
index de15f92..aa81afd 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -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;
 }
 
 /*