From: Stephen Rothwell <sfr@canb.auug.org.au>
Date: Thu, 11 Feb 2016 02:43:47 +0000 (+1100)
Subject: Merge remote-tracking branch 'tty/tty-next'
X-Git-Tag: next-20160211~19
X-Git-Url: https://git.karo-electronics.de/?p=karo-tx-linux.git;a=commitdiff_plain;h=2292705bd6c27b3ed2f83db8d2268d8006c027d7

Merge remote-tracking branch 'tty/tty-next'
---

2292705bd6c27b3ed2f83db8d2268d8006c027d7
diff --cc drivers/tty/pty.c
index 2348fa613707,78170e7aa3a3..e16a49b507ef
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@@ -674,21 -660,10 +660,17 @@@ static int pty_unix98_install(struct tt
  	return pty_common_install(driver, tty, false);
  }
  
- static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
- {
- }
- 
  /* this is called once with whichever end is closed last */
- static void pty_unix98_shutdown(struct tty_struct *tty)
+ static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
  {
 -	devpts_kill_index(tty->driver_data, tty->index);
 +	struct inode *ptmx_inode;
 +
 +	if (tty->driver->subtype == PTY_TYPE_MASTER)
 +		ptmx_inode = tty->driver_data;
 +	else
 +		ptmx_inode = tty->link->driver_data;
 +	devpts_kill_index(ptmx_inode, tty->index);
 +	devpts_del_ref(ptmx_inode);
  }
  
  static const struct tty_operations ptm_unix98_ops = {
diff --cc drivers/tty/tty_io.c
index a7eacef1bd22,8d26ed79bb4c..c14c45fefa70
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@@ -2003,6 -2008,69 +2008,68 @@@ static struct tty_driver *tty_lookup_dr
  	return driver;
  }
  
+ /**
+  *	tty_open_by_driver	-	open a tty device
+  *	@device: dev_t of device to open
+  *	@inode: inode of device file
+  *	@filp: file pointer to tty
+  *
+  *	Performs the driver lookup, checks for a reopen, or otherwise
+  *	performs the first-time tty initialization.
+  *
+  *	Returns the locked initialized or re-opened &tty_struct
+  *
+  *	Claims the global tty_mutex to serialize:
+  *	  - concurrent first-time tty initialization
+  *	  - concurrent tty driver removal w/ lookup
+  *	  - concurrent tty removal from driver table
+  */
+ 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);
++		tty_kref_put(tty);  /* drop kref from tty_driver_lookup_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, index);
+ 		mutex_unlock(&tty_mutex);
+ 	}
+ out:
+ 	tty_driver_kref_put(driver);
+ 	return tty;
+ }
+ 
  /**
   *	tty_open		-	open a tty device
   *	@inode: inode of device file
diff --cc drivers/tty/tty_mutex.c
index dfa9ec03fa8e,75351e4b77df..d8bae67a6174
--- a/drivers/tty/tty_mutex.c
+++ b/drivers/tty/tty_mutex.c
@@@ -26,13 -24,10 +26,13 @@@ int tty_lock_interruptible(struct tty_s
  	if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty))
  		return -EIO;
  	tty_kref_get(tty);
 -	return mutex_lock_interruptible(&tty->legacy_mutex);
 +	ret = mutex_lock_interruptible(&tty->legacy_mutex);
 +	if (ret)
 +		tty_kref_put(tty);
 +	return ret;
  }
  
- void __lockfunc tty_unlock(struct tty_struct *tty)
+ void tty_unlock(struct tty_struct *tty)
  {
  	if (WARN(tty->magic != TTY_MAGIC, "U Bad %p\n", tty))
  		return;