Merge branch 'writeback-workqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq into for-3.10/core

Tejun writes:

-----

This is the pull request for the earlier patchset[1] with the same
name.  It's only three patches (the first one was committed to
workqueue tree) but the merge strategy is a bit involved due to the
dependencies.

* Because the conversion needs features from wq/for-3.10,
  block/for-3.10/core is based on rc3, and wq/for-3.10 has conflicts
  with rc3, I pulled mainline (rc5) into wq/for-3.10 to prevent those
  workqueue conflicts from flaring up in block tree.

* Resolving the issue that Jan and Dave raised about debugging
  requires arch-wide changes.  The patchset is being worked on[2] but
  it'll have to go through -mm after these changes show up in -next,
  and not included in this pull request.

The three commits are located in the following git branch.

  git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git writeback-workqueue

Pulling it into block/for-3.10/core produces a conflict in
drivers/md/raid5.c between the following two commits.

  e3620a3ad5 ("MD RAID5: Avoid accessing gendisk or queue structs when not available")
  2f6db2a707 ("raid5: use bio_reset()")

The conflict is trivial - one removes an "if ()" conditional while the
other removes "rbi->bi_next = NULL" right above it.  We just need to
remove both.  The merged branch is available at

  git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git block-test-merge

so that you can use it for verification.  The test merge commit has
proper merge description.

While these changes are a bit of pain to route, they make code simpler
and even have, while minute, measureable performance gain[3] even on a
workload which isn't particularly favorable to showing the benefits of
this conversion.

----

Fixed up the conflict.

Conflicts:
	drivers/md/raid5.c

Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 19 insertions, 20 deletions

diff --git a/drivers/media/platform/s5p-fimc/fimc-mdevice.c b/drivers/media/platform/s5p-fimc/fimc-mdevice.c
index a17fcb2d5d41..cd38d708ab58 100644
--- a/drivers/media/platform/s5p-fimc/fimc-mdevice.c
+++ b/drivers/media/platform/s5p-fimc/fimc-mdevice.c
@@ -827,7 +827,7 @@ static int fimc_md_link_notify(struct media_pad *source,
 	struct fimc_pipeline *pipeline;
 	struct v4l2_subdev *sd;
 	struct mutex *lock;
-	int ret = 0;
+	int i, ret = 0;
 	int ref_count;
 
 	if (media_entity_type(sink->entity) != MEDIA_ENT_T_V4L2_SUBDEV)
@@ -854,29 +854,28 @@ static int fimc_md_link_notify(struct media_pad *source,
 		return 0;
 	}
 
+	mutex_lock(lock);
+	ref_count = fimc ? fimc->vid_cap.refcnt : fimc_lite->ref_count;
+
 	if (!(flags & MEDIA_LNK_FL_ENABLED)) {
-		int i;
-		mutex_lock(lock);
-		ret = __fimc_pipeline_close(pipeline);
+		if (ref_count > 0) {
+			ret = __fimc_pipeline_close(pipeline);
+			if (!ret && fimc)
+				fimc_ctrls_delete(fimc->vid_cap.ctx);
+		}
 		for (i = 0; i < IDX_MAX; i++)
 			pipeline->subdevs[i] = NULL;
-		if (fimc)
-			fimc_ctrls_delete(fimc->vid_cap.ctx);
-		mutex_unlock(lock);
-		return ret;
+	} else if (ref_count > 0) {
+		/*
+		 * Link activation. Enable power of pipeline elements only if
+		 * the pipeline is already in use, i.e. its video node is open.
+		 * Recreate the controls destroyed during the link deactivation.
+		 */
+		ret = __fimc_pipeline_open(pipeline,
+					   source->entity, true);
+		if (!ret && fimc)
+			ret = fimc_capture_ctrls_create(fimc);
 	}
-	/*
-	 * Link activation. Enable power of pipeline elements only if the
-	 * pipeline is already in use, i.e. its video node is opened.
-	 * Recreate the controls destroyed during the link deactivation.
-	 */
-	mutex_lock(lock);
-
-	ref_count = fimc ? fimc->vid_cap.refcnt : fimc_lite->ref_count;
-	if (ref_count > 0)
-		ret = __fimc_pipeline_open(pipeline, source->entity, true);
-	if (!ret && fimc)
-		ret = fimc_capture_ctrls_create(fimc);
 
 	mutex_unlock(lock);
 	return ret ? -EPIPE : ret;