block: add io_context->active_ref

Currently ioc->nr_tasks is used to decide two things - whether an ioc
is done issuing IOs and whether it's shared by multiple tasks.  This
patch separate out the first into ioc->active_ref, which is acquired
and released using {get|put}_io_context_active() respectively.

This will be used to associate bio's with a given task.  This patch
doesn't introduce any visible behavior change.

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, 2 insertions, 2 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 9e386d9bcb79..9a4eac490e0b 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1865,7 +1865,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
          * task has exited, don't wait
          */
         cic = cfqd->active_cic;
-        if (!cic || !atomic_read(&cic->icq.ioc->nr_tasks))
+        if (!cic || !atomic_read(&cic->icq.ioc->active_ref))
                 return;
 
         /*
@@ -2841,7 +2841,7 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 
         if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE))
                 enable_idle = 0;
-        else if (!atomic_read(&cic->icq.ioc->nr_tasks) ||
+        else if (!atomic_read(&cic->icq.ioc->active_ref) ||
                  !cfqd->cfq_slice_idle ||
                  (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq)))
                 enable_idle = 0;