linux-kernel - linux-next: manual merge of the tty tree with the tty.current tree

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Date:	Mon, 8 Feb 2016 13:16:29 +1100
From:	Stephen Rothwell <sfr@...b.auug.org.au>
To:	Greg KH <greg@...ah.com>
Cc:	linux-next@...r.kernel.org, linux-kernel@...r.kernel.org,
	Peter Hurley <peter@...leysoftware.com>
Subject: linux-next: manual merge of the tty tree with the tty.current tree

Hi Greg,

Today's linux-next merge of the tty tree got a conflict in:

  drivers/tty/tty_io.c

between commit:

  e9036d066236 ("tty: Drop krefs for interrupted tty lock")

from the tty.current tree and commit:

  d6203d0c7b73 ("tty: Refactor tty_open()")

from the tty tree.

I fixed it up (I think - see below) and can carry the fix as necessary
(no action is required).

-- 
Cheers,
Stephen Rothwell

diff --cc drivers/tty/tty_io.c
index a7eacef1bd22,8d26ed79bb4c..000000000000
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@@ -2004,6 -2009,69 +2009,68 @@@ static struct tty_driver *tty_lookup_dr
  }
  
  /**
+  *	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
   *	@filp: file pointer to tty