spi_mpc83xx: split mpc83xx_spi_work() into two routines

mpc83xx_spi_work() is quite large, with up to five indentation levels and
is quite difficult to read.

So, split the function in two parts:
1. mpc83xx_spi_work() now only traverse queued spi messages;
2. mpc83xx_spi_do_one_msg() only manages single messages.

There should be no functional changes.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/spi/spi_mpc83xx.c

@@ -350,26 +350,14 @@ static int mpc83xx_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
 	return mpc83xx_spi->count;
 }
 
-static void mpc83xx_spi_work(struct work_struct *work)
+static void mpc83xx_spi_do_one_msg(struct spi_message *m)
 {
-	struct mpc83xx_spi *mpc83xx_spi =
-		container_of(work, struct mpc83xx_spi, work);
-
-	spin_lock_irq(&mpc83xx_spi->lock);
-	mpc83xx_spi->busy = 1;
-	while (!list_empty(&mpc83xx_spi->queue)) {
-		struct spi_message *m;
-		struct spi_device *spi;
-		struct spi_transfer *t = NULL;
-		unsigned cs_change;
-		int status, nsecs = 50;
+	struct spi_device *spi = m->spi;
+	struct spi_transfer *t;
+	unsigned int cs_change;
+	const int nsecs = 50;
+	int status;
 
-		m = container_of(mpc83xx_spi->queue.next,
-				struct spi_message, queue);
-		list_del_init(&m->queue);
-		spin_unlock_irq(&mpc83xx_spi->lock);
-
-		spi = m->spi;
 	cs_change = 1;
 	status = 0;
 	list_for_each_entry(t, &m->transfers, transfer_list) {
@@ -415,6 +403,23 @@ static void mpc83xx_spi_work(struct work_struct *work)
 	}
 
 	mpc83xx_spi_setup_transfer(spi, NULL);
+}
+
+static void mpc83xx_spi_work(struct work_struct *work)
+{
+	struct mpc83xx_spi *mpc83xx_spi = container_of(work, struct mpc83xx_spi,
+						       work);
+
+	spin_lock_irq(&mpc83xx_spi->lock);
+	mpc83xx_spi->busy = 1;
+	while (!list_empty(&mpc83xx_spi->queue)) {
+		struct spi_message *m = container_of(mpc83xx_spi->queue.next,
+						   struct spi_message, queue);
+
+		list_del_init(&m->queue);
+		spin_unlock_irq(&mpc83xx_spi->lock);
+
+		mpc83xx_spi_do_one_msg(m);
 
 		spin_lock_irq(&mpc83xx_spi->lock);
 	}