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, 10 insertions, 6 deletions

diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 809fb329eca5..b8051fa61911 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -219,7 +219,6 @@ struct moschip_port {
 	char open;
 	char open_ports;
 	wait_queue_head_t wait_chase;	/* for handling sleeping while waiting for chase to finish */
-	wait_queue_head_t delta_msr_wait;	/* for handling sleeping while waiting for msr change to happen */
 	int delta_msr_cond;
 	struct async_icount icount;
 	struct usb_serial_port *port;	/* loop back to the owner of this object */
@@ -423,6 +422,9 @@ static void mos7840_handle_new_msr(struct moschip_port *port, __u8 new_msr)
 			icount->rng++;
 			smp_wmb();
 		}
+
+		mos7840_port->delta_msr_cond = 1;
+		wake_up_interruptible(&port->port->delta_msr_wait);
 	}
 }
 
@@ -1127,7 +1129,6 @@ static int mos7840_open(struct tty_struct *tty, struct usb_serial_port *port)
 
 	/* initialize our wait queues */
 	init_waitqueue_head(&mos7840_port->wait_chase);
-	init_waitqueue_head(&mos7840_port->delta_msr_wait);
 
 	/* initialize our icount structure */
 	memset(&(mos7840_port->icount), 0x00, sizeof(mos7840_port->icount));
@@ -2017,8 +2018,6 @@ static void mos7840_change_port_settings(struct tty_struct *tty,
 			mos7840_port->read_urb_busy = false;
 		}
 	}
-	wake_up(&mos7840_port->delta_msr_wait);
-	mos7840_port->delta_msr_cond = 1;
 	dev_dbg(&port->dev, "%s - mos7840_port->shadowLCR is End %x\n", __func__,
 		mos7840_port->shadowLCR);
 }
@@ -2219,13 +2218,18 @@ static int mos7840_ioctl(struct tty_struct *tty,
 		while (1) {
 			/* interruptible_sleep_on(&mos7840_port->delta_msr_wait); */
 			mos7840_port->delta_msr_cond = 0;
-			wait_event_interruptible(mos7840_port->delta_msr_wait,
-						 (mos7840_port->
+			wait_event_interruptible(port->delta_msr_wait,
+						 (port->serial->disconnected ||
+						  mos7840_port->
 						  delta_msr_cond == 1));
 
 			/* see if a signal did it */
 			if (signal_pending(current))
 				return -ERESTARTSYS;
+
+			if (port->serial->disconnected)
+				return -EIO;
+
 			cnow = mos7840_port->icount;
 			smp_rmb();
 			if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&