[PATCH 11/12] tty: Refactor tty_open()

[Peter Hurley]

Extract the driver lookup and reopen-or-initialize logic into helper
function tty_open_by_driver(). No functional change.

Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---
 drivers/tty/tty_io.c | 98 +++++++++++++++++++++++++++-------------------------
 1 file changed, 50 insertions(+), 48 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 1792a20..eb391d4 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2004,6 +2004,54 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
 	return driver;
 }
 
+static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
+					     struct file *filp)
+{
+	struct tty_struct *tty;
+	struct tty_driver *driver = NULL;
+	int index = -1;
+	int retval;
+
+	mutex_lock(&tty_mutex);
+	driver = tty_lookup_driver(device, filp, &index);
+	if (IS_ERR(driver)) {
+		mutex_unlock(&tty_mutex);
+		return ERR_CAST(driver);
+	}
+
+	/* check whether we're reopening an existing tty */
+	tty = tty_driver_lookup_tty(driver, inode, index);
+	if (IS_ERR(tty)) {
+		mutex_unlock(&tty_mutex);
+		goto out;
+	}
+
+	if (tty) {
+		mutex_unlock(&tty_mutex);
+		retval = tty_lock_interruptible(tty);
+		if (retval) {
+			if (retval == -EINTR)
+				retval = -ERESTARTSYS;
+			tty = ERR_PTR(retval);
+			goto out;
+		}
+		/* safe to drop the kref from tty_driver_lookup_tty() */
+		tty_kref_put(tty);
+		retval = tty_reopen(tty);
+		if (retval < 0) {
+			tty_unlock(tty);
+			tty = ERR_PTR(retval);
+		}
+	} else { /* Returns with the tty_lock held for now */
+		tty = tty_init_dev(driver, inode, index);
+		mutex_unlock(&tty_mutex);
+	}
+
+out:
+	tty_driver_kref_put(driver);
+	return tty;
+}
+
 /**
  *	tty_open		-	open a tty device
  *	@inode: inode of device file
@@ -2032,8 +2080,6 @@ static int tty_open(struct inode *inode, struct file *filp)
 {
 	struct tty_struct *tty;
 	int noctty, retval;
-	struct tty_driver *driver = NULL;
-	int index;
 	dev_t device = inode->i_rdev;
 	unsigned saved_flags = filp->f_flags;
 
@@ -2044,47 +2090,9 @@ retry_open:
 	if (retval)
 		return -ENOMEM;
 
-	index  = -1;
-	retval = 0;
-
 	tty = tty_open_current_tty(device, filp);
-	if (!tty) {
-		mutex_lock(&tty_mutex);
-		driver = tty_lookup_driver(device, filp, &index);
-		if (IS_ERR(driver)) {
-			retval = PTR_ERR(driver);
-			goto err_unlock;
-		}
-
-		/* check whether we're reopening an existing tty */
-		tty = tty_driver_lookup_tty(driver, inode, index);
-		if (IS_ERR(tty)) {
-			retval = PTR_ERR(tty);
-			goto err_unlock;
-		}
-
-		if (tty) {
-			mutex_unlock(&tty_mutex);
-			retval = tty_lock_interruptible(tty);
-			if (retval) {
-				if (retval == -EINTR)
-					retval = -ERESTARTSYS;
-				goto err_unref;
-			}
-			/* safe to drop the kref from tty_driver_lookup_tty() */
-			tty_kref_put(tty);
-			retval = tty_reopen(tty);
-			if (retval < 0) {
-				tty_unlock(tty);
-				tty = ERR_PTR(retval);
-			}
-		} else { /* Returns with the tty_lock held for now */
-			tty = tty_init_dev(driver, inode, index);
-			mutex_unlock(&tty_mutex);
-		}
-
-		tty_driver_kref_put(driver);
-	}
+	if (!tty)
+		tty = tty_open_by_driver(device, inode, filp);
 
 	if (IS_ERR(tty)) {
 		retval = PTR_ERR(tty);
@@ -2157,12 +2165,6 @@ retry_open:
 	read_unlock(&tasklist_lock);
 	tty_unlock(tty);
 	return 0;
-err_unlock:
-	mutex_unlock(&tty_mutex);
-err_unref:
-	/* after locks to avoid deadlock */
-	if (!IS_ERR_OR_NULL(driver))
-		tty_driver_kref_put(driver);
 err_file:
 	tty_free_file(filp);
 	return retval;
-- 
2.6.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/