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, 7 insertions, 6 deletions

diff --git a/drivers/usb/serial/mct_u232.c b/drivers/usb/serial/mct_u232.c
index a64d420f687b..06d5a60be2c4 100644
--- a/drivers/usb/serial/mct_u232.c
+++ b/drivers/usb/serial/mct_u232.c
@@ -114,8 +114,6 @@ struct mct_u232_private {
 	unsigned char	     last_msr;      /* Modem Status Register */
 	unsigned int	     rx_flags;      /* Throttling flags */
 	struct async_icount  icount;
-	wait_queue_head_t    msr_wait;	/* for handling sleeping while waiting
-						for msr change to happen */
 };
 
 #define THROTTLED		0x01
@@ -409,7 +407,6 @@ static int mct_u232_port_probe(struct usb_serial_port *port)
 		return -ENOMEM;
 
 	spin_lock_init(&priv->lock);
-	init_waitqueue_head(&priv->msr_wait);
 
 	usb_set_serial_port_data(port, priv);
 
@@ -601,7 +598,7 @@ static void mct_u232_read_int_callback(struct urb *urb)
 		tty_kref_put(tty);
 	}
 #endif
-	wake_up_interruptible(&priv->msr_wait);
+	wake_up_interruptible(&port->delta_msr_wait);
 	spin_unlock_irqrestore(&priv->lock, flags);
 exit:
 	retval = usb_submit_urb(urb, GFP_ATOMIC);
@@ -810,13 +807,17 @@ static int  mct_u232_ioctl(struct tty_struct *tty,
 		cprev = mct_u232_port->icount;
 		spin_unlock_irqrestore(&mct_u232_port->lock, flags);
 		for ( ; ; ) {
-			prepare_to_wait(&mct_u232_port->msr_wait,
+			prepare_to_wait(&port->delta_msr_wait,
 					&wait, TASK_INTERRUPTIBLE);
 			schedule();
-			finish_wait(&mct_u232_port->msr_wait, &wait);
+			finish_wait(&port->delta_msr_wait, &wait);
 			/* see if a signal did it */
 			if (signal_pending(current))
 				return -ERESTARTSYS;
+
+			if (port->serial->disconnected)
+				return -EIO;
+
 			spin_lock_irqsave(&mct_u232_port->lock, flags);
 			cnow = mct_u232_port->icount;
 			spin_unlock_irqrestore(&mct_u232_port->lock, flags);