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[PATCH]: Factor out PTY index allocation [message #29550] Wed, 16 April 2008 22:17 Go to next message
Sukadev Bhattiprolu is currently offline  Sukadev Bhattiprolu
Messages: 413
Registered: August 2006
Senior Member
We noticed this while working on pts namespaces and believe this might
be an useful change even as we rework our pts/device namespace approach.

---

From: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Subject: [PATCH]: Factor out PTY index allocation

Factor out the code used to allocate/free a pts index into new interfaces,
devpts_new_index() and devpts_kill_index().  This localizes the external
data structures used in managing the pts indices.

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Serge Hallyn<serue@us.ibm.com>
Signed-off-by: Matt Helsley<matthltc@us.ibm.com>

---
 drivers/char/tty_io.c     |   40 ++++++----------------------------------
 fs/devpts/inode.c         |   42 +++++++++++++++++++++++++++++++++++++++++-
 include/linux/devpts_fs.h |    4 ++++
 3 files changed, 51 insertions(+), 35 deletions(-)

Index: 2.6.25-rc8-mm2/include/linux/devpts_fs.h
===================================================================
--- 2.6.25-rc8-mm2.orig/include/linux/devpts_fs.h	2008-01-26 09:49:16.000000000 -0800
+++ 2.6.25-rc8-mm2/include/linux/devpts_fs.h	2008-04-16 09:51:15.000000000 -0700
@@ -17,6 +17,8 @@
 
 #ifdef CONFIG_UNIX98_PTYS
 
+int devpts_new_index(void);
+void devpts_kill_index(int idx);
 int devpts_pty_new(struct tty_struct *tty);      /* mknod in devpts */
 struct tty_struct *devpts_get_tty(int number);	 /* get tty structure */
 void devpts_pty_kill(int number);		 /* unlink */
@@ -24,6 +26,8 @@ void devpts_pty_kill(int number);		 /* u
 #else
 
 /* Dummy stubs in the no-pty case */
+static inline int devpts_new_index(void) { return -EINVAL; }
+static inline void devpts_kill_index(int idx) { }
 static inline int devpts_pty_new(struct tty_struct *tty) { return -EINVAL; }
 static inline struct tty_struct *devpts_get_tty(int number) { return NULL; }
 static inline void devpts_pty_kill(int number) { }
Index: 2.6.25-rc8-mm2/drivers/char/tty_io.c
===================================================================
--- 2.6.25-rc8-mm2.orig/drivers/char/tty_io.c	2008-04-16 09:51:11.000000000 -0700
+++ 2.6.25-rc8-mm2/drivers/char/tty_io.c	2008-04-16 09:51:15.000000000 -0700
@@ -91,7 +91,6 @@
 #include <linux/module.h>
 #include <linux/smp_lock.h>
 #include <linux/device.h>
-#include <linux/idr.h>
 #include <linux/wait.h>
 #include <linux/bitops.h>
 #include <linux/delay.h>
@@ -137,9 +136,6 @@ EXPORT_SYMBOL(tty_mutex);
 
 #ifdef CONFIG_UNIX98_PTYS
 extern struct tty_driver *ptm_driver;	/* Unix98 pty masters; for /dev/ptmx */
-extern int pty_limit;			/* Config limit on Unix98 ptys */
-static DEFINE_IDR(allocated_ptys);
-static DEFINE_MUTEX(allocated_ptys_lock);
 static int ptmx_open(struct inode *, struct file *);
 #endif
 
@@ -2636,15 +2632,9 @@ static void release_dev(struct file *fil
 	 */
 	release_tty(tty, idx);
 
-#ifdef CONFIG_UNIX98_PTYS
 	/* Make this pty number available for reallocation */
-	if (devpts) {
-		mutex_lock(&allocated_ptys_lock);
-		idr_remove(&allocated_ptys, idx);
-		mutex_unlock(&allocated_ptys_lock);
-	}
-#endif
-
+	if (devpts)
+		devpts_kill_index(idx);
 }
 
 /**
@@ -2800,29 +2790,13 @@ static int ptmx_open(struct inode *inode
 	struct tty_struct *tty;
 	int retval;
 	int index;
-	int idr_ret;
 
 	nonseekable_open(inode, filp);
 
 	/* find a device that is not in use. */
-	mutex_lock(&allocated_ptys_lock);
-	if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) {
-		mutex_unlock(&allocated_ptys_lock);
-		return -ENOMEM;
-	}
-	idr_ret = idr_get_new(&allocated_ptys, NULL, &index);
-	if (idr_ret < 0) {
-		mutex_unlock(&allocated_ptys_lock);
-		if (idr_ret == -EAGAIN)
-			return -ENOMEM;
-		return -EIO;
-	}
-	if (index >= pty_limit) {
-		idr_remove(&allocated_ptys, index);
-		mutex_unlock(&allocated_ptys_lock);
-		return -EIO;
-	}
-	mutex_unlock(&allocated_ptys_lock);
+	index = devpts_new_index();
+	if (index < 0)
+		return index;
 
 	mutex_lock(&tty_mutex);
 	retval = init_dev(ptm_driver, index, &tty);
@@ -2847,9 +2821,7 @@ out1:
 	release_dev(filp);
 	return retval;
 out:
-	mutex_lock(&allocated_ptys_lock);
-	idr_remove(&allocated_ptys, index);
-	mutex_unlock(&allocated_ptys_lock);
+	devpts_kill_index(index);
 	return retval;
 }
 #endif
Index: 2.6.25-rc8-mm2/fs/devpts/inode.c
===================================================================
--- 2.6.25-rc8-mm2.orig/fs/devpts/inode.c	2008-02-27 15:17:59.000000000 -0800
+++ 2.6.25-rc8-mm2/fs/devpts/inode.c	2008-04-16 09:51:15.000000000 -0700
@@ -17,6 +17,7 @@
 #include <linux/namei.h>
 #include <linux/mount.h>
 #include <linux/tty.h>
+#include <linux/idr.h>
 #include <linux/devpts_fs.h>
 #include <linux/parser.h>
 #include <linux/fsnotify.h>
@@ -26,6 +27,10 @@
 
 #define DEVPTS_DEFAULT_MODE 0600
 
+extern int pty_limit;			/* Config limit on Unix98 ptys */
+static DEFINE_IDR(allocated_ptys);
+static DECLARE_MUTEX(allocated_ptys_lock);
+
 static struct vfsmount *devpts_mnt;
 static struct dentry *devpts_root;
 
@@ -171,9 +176,44 @@ static struct dentry *get_node(int num)
 	return lookup_one_len(s, root, sprintf(s, "%d", num));
 }
 
+int devpts_new_index(void)
+{
+	int index;
+	int idr_ret;
+
+retry:
+	if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) {
+		return -ENOMEM;
+	}
+
+	down(&allocated_ptys_lock);
+	idr_ret = idr_get_new(&allocated_ptys, NULL, &index);
+	if (idr_ret < 0) {
+		up(&allocated_ptys_lock);
+		if (idr_ret == -EAGAIN)
+			goto retry;
+		return -EIO;
+	}
+
+	if (index >= pty_limit) {
+		idr_remove(&allocated_ptys, index);
+		up(&allocated_ptys_lock);
+		return -EIO;
+	}
+	up(&allocated_ptys_lock);
+	return index;
+}
+
+void devpts_kill_index(int idx)
+{
+	down(&allocated_ptys_lock);
+	idr_remove(&allocated_ptys, idx);
+	up(&allocated_ptys_lock);
+}
+
 int devpts_pty_new(struct tty_struct *tty)
 {
-	int number = tty->index;
+	int number = tty->index; /* tty layer puts index from devpts_new_index() in here */
 	struct tty_driver *driver = tty->driver;
 	dev_t device = MKDEV(driver->major, driver->minor_start+number);
 	struct dentry *dentry;
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Re: [PATCH]: Factor out PTY index allocation [message #29586 is a reply to message #29550] Thu, 17 April 2008 15:42 Go to previous messageGo to next message
serue is currently offline  serue
Messages: 750
Registered: February 2006
Senior Member
Quoting sukadev@us.ibm.com (sukadev@us.ibm.com):
> We noticed this while working on pts namespaces and believe this might
> be an useful change even as we rework our pts/device namespace approach.
> 
> ---
> 
> From: Sukadev Bhattiprolu <sukadev@us.ibm.com>
> Subject: [PATCH]: Factor out PTY index allocation
> 
> Factor out the code used to allocate/free a pts index into new interfaces,
> devpts_new_index() and devpts_kill_index().  This localizes the external
> data structures used in managing the pts indices.
> 
> Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
> Signed-off-by: Serge Hallyn<serue@us.ibm.com>
> Signed-off-by: Matt Helsley<matthltc@us.ibm.com>

No traces of devpts namespaces here, so I assume this should be
non-offensive and fine for inclusion.

thanks,
-serge

> ---
>  drivers/char/tty_io.c     |   40 ++++++----------------------------------
>  fs/devpts/inode.c         |   42 +++++++++++++++++++++++++++++++++++++++++-
>  include/linux/devpts_fs.h |    4 ++++
>  3 files changed, 51 insertions(+), 35 deletions(-)
> 
> Index: 2.6.25-rc8-mm2/include/linux/devpts_fs.h
> ===================================================================
> --- 2.6.25-rc8-mm2.orig/include/linux/devpts_fs.h	2008-01-26 09:49:16.000000000 -0800
> +++ 2.6.25-rc8-mm2/include/linux/devpts_fs.h	2008-04-16 09:51:15.000000000 -0700
> @@ -17,6 +17,8 @@
> 
>  #ifdef CONFIG_UNIX98_PTYS
> 
> +int devpts_new_index(void);
> +void devpts_kill_index(int idx);
>  int devpts_pty_new(struct tty_struct *tty);      /* mknod in devpts */
>  struct tty_struct *devpts_get_tty(int number);	 /* get tty structure */
>  void devpts_pty_kill(int number);		 /* unlink */
> @@ -24,6 +26,8 @@ void devpts_pty_kill(int number);		 /* u
>  #else
> 
>  /* Dummy stubs in the no-pty case */
> +static inline int devpts_new_index(void) { return -EINVAL; }
> +static inline void devpts_kill_index(int idx) { }
>  static inline int devpts_pty_new(struct tty_struct *tty) { return -EINVAL; }
>  static inline struct tty_struct *devpts_get_tty(int number) { return NULL; }
>  static inline void devpts_pty_kill(int number) { }
> Index: 2.6.25-rc8-mm2/drivers/char/tty_io.c
> ===================================================================
> --- 2.6.25-rc8-mm2.orig/drivers/char/tty_io.c	2008-04-16 09:51:11.000000000 -0700
> +++ 2.6.25-rc8-mm2/drivers/char/tty_io.c	2008-04-16 09:51:15.000000000 -0700
> @@ -91,7 +91,6 @@
>  #include <linux/module.h>
>  #include <linux/smp_lock.h>
>  #include <linux/device.h>
> -#include <linux/idr.h>
>  #include <linux/wait.h>
>  #include <linux/bitops.h>
>  #include <linux/delay.h>
> @@ -137,9 +136,6 @@ EXPORT_SYMBOL(tty_mutex);
> 
>  #ifdef CONFIG_UNIX98_PTYS
>  extern struct tty_driver *ptm_driver;	/* Unix98 pty masters; for /dev/ptmx */
> -extern int pty_limit;			/* Config limit on Unix98 ptys */
> -static DEFINE_IDR(allocated_ptys);
> -static DEFINE_MUTEX(allocated_ptys_lock);
>  static int ptmx_open(struct inode *, struct file *);
>  #endif
> 
> @@ -2636,15 +2632,9 @@ static void release_dev(struct file *fil
>  	 */
>  	release_tty(tty, idx);
> 
> -#ifdef CONFIG_UNIX98_PTYS
>  	/* Make this pty number available for reallocation */
> -	if (devpts) {
> -		mutex_lock(&allocated_ptys_lock);
> -		idr_remove(&allocated_ptys, idx);
> -		mutex_unlock(&allocated_ptys_lock);
> -	}
> -#endif
> -
> +	if (devpts)
> +		devpts_kill_index(idx);
>  }
> 
>  /**
> @@ -2800,29 +2790,13 @@ static int ptmx_open(struct inode *inode
>  	struct tty_struct *tty;
>  	int retval;
>  	int index;
> -	int idr_ret;
> 
>  	nonseekable_open(inode, filp);
> 
>  	/* find a device that is not in use. */
> -	mutex_lock(&allocated_ptys_lock);
> -	if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) {
> -		mutex_unlock(&allocated_ptys_lock);
> -		return -ENOMEM;
> -	}
> -	idr_ret = idr_get_new(&allocated_ptys, NULL, &index);
> -	if (idr_ret < 0) {
> -		mutex_unlock(&allocated_ptys_lock);
> -		if (idr_ret == -EAGAIN)
> -			return -ENOMEM;
> -		return -EIO;
> -	}
> -	if (index >= pty_limit) {
> -		idr_remove(&allocated_ptys, index);
> -		mutex_unlock(&allocated_ptys_lock);
> -		return -EIO;
> -	}
> -	mutex_unlock(&allocated_ptys_lock);
> +	index = devpts_new_index();
> +	if (index < 0)
> +		return index;
> 
>  	mutex_lock(&tty_mutex);
>  	retval = init_dev(ptm_driver, index, &tty);
> @@ -2847,9 +2821,7 @@ out1:
>  	release_dev(filp);
>  	return retval;
>  out:
> -	mutex_lock(&allocated_ptys_lock);
> -	idr_remove(&allocated_ptys, index);
> -	mutex_unlock(&allocated_ptys_lock);
> +	devpts_kill_index(index);
>  	return retval;
>  }
>  #endif
> Index: 2.6.25-rc8-mm2/fs/devpts/inode.c
> ===================================================================
> --- 2.6.25-rc8-mm2.orig/fs/devpts/inode.c	2008-02-27 15:17:59.000000000 -0800
> +++ 2.6.25-rc8-mm2/fs/devpts/inode.c	2008-04-16 09:51:15.000000000 -0700
> @@ -17,6 +17,7 @@
>  #include <linux/namei.h>
>  #include <linux/mount.h>
>  #include <linux/tty.h>
> +#include <linux/idr.h>
>  #include <linux/devpts_fs.h>
>  #include <linux/parser.h>
>  #include <linux/fsnotify.h>
> @@ -26,6 +27,10 @@
> 
>  #define DEVPTS_DEFAULT_MODE 0600
> 
> +extern int pty_limit;			/* Config limit on Unix98 ptys */
> +static DEFINE_IDR(allocated_ptys);
> +static DECLARE_MUTEX(allocated_ptys_lock);
> +
>  static struct vfsmount *devpts_mnt;
>  static struct dentry *devpts_root;
> 
> @@ -171,9 +176,44 @@ static struct dentry *get_node(int num)
>  	return lookup_one_len(s, root, sprintf(s, "%d", num));
>  }
> 
> +int devpts_new_index(void)
> +{
> +	int index;
> +	int idr_ret;
> +
> +retry:
> +	if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) {
> +		return -ENOMEM;
> +	}
> +
> +	down(&allocated_ptys_lock);
> +	idr_ret = idr_get_new(&allocated_ptys, NULL, &index);
> +	if (idr_ret < 0) {
> +		up(&allocated_ptys_lock);
> +		if (idr_ret == -EAGAIN)
> +			goto retry;
> +		return -EIO;
> +	}
> +
> +	if (index >= pty_limit) {
> +		idr_remove(&allocated_ptys, index);
> +		up(&allocated_ptys_lock);
> +		return -EIO;
> +	}
> +	up(&allocated_ptys_lock);
> +	return index;
> +}
> +
> +void devpts_kill_index(int idx)
> +{
> +	down(&allocated_ptys_lock);
> +	idr_remove(&allocated_ptys, idx);
> +	up(&allocated_ptys_lock);
> +}
> +
>  int devpts_pty_new(struct tty_struct *tty)
>  {
> -	int number = tty->index;
> +	int number = tty->index; /* tty layer puts index from devpts_new_index() in here */
>  	struct tty_driver *driver = tty->driver;
>  	dev_t device = MKDEV(driver->major, driver->minor_start+number);
>  	struct dentry *dentry;
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Re: [PATCH]: Factor out PTY index allocation [message #29588 is a reply to message #29586] Thu, 17 April 2008 16:05 Go to previous messageGo to next message
hpa is currently offline  hpa
Messages: 38
Registered: January 2007
Member
Serge E. Hallyn wrote:
> Quoting sukadev@us.ibm.com (sukadev@us.ibm.com):
>> We noticed this while working on pts namespaces and believe this might
>> be an useful change even as we rework our pts/device namespace approach.
>>
>> ---
>>
>> From: Sukadev Bhattiprolu <sukadev@us.ibm.com>
>> Subject: [PATCH]: Factor out PTY index allocation
>>
>> Factor out the code used to allocate/free a pts index into new interfaces,
>> devpts_new_index() and devpts_kill_index().  This localizes the external
>> data structures used in managing the pts indices.
>>
>> Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
>> Signed-off-by: Serge Hallyn<serue@us.ibm.com>
>> Signed-off-by: Matt Helsley<matthltc@us.ibm.com>
> 
> No traces of devpts namespaces here, so I assume this should be
> non-offensive and fine for inclusion.
> 

Acked-by: H. Peter Anvin <hpa@zytor.com>
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Re: [PATCH]: Factor out PTY index allocation [message #29597 is a reply to message #29550] Thu, 17 April 2008 21:17 Go to previous messageGo to next message
akpm is currently offline  akpm
Messages: 224
Registered: March 2007
Senior Member
On Wed, 16 Apr 2008 15:17:23 -0700
sukadev@us.ibm.com wrote:

> Factor out the code used to allocate/free a pts index into new interfaces,
> devpts_new_index() and devpts_kill_index().  This localizes the external
> data structures used in managing the pts indices.

err...

> -	mutex_lock(&allocated_ptys_lock);
> +	down(&allocated_ptys_lock);

Why the mutex-to-semaphore conversion?


--- a/fs/devpts/inode.c~devpts-factor-out-pty-index-allocation-fix
+++ a/fs/devpts/inode.c
@@ -17,6 +17,7 @@
 #include <linux/namei.h>
 #include <linux/mount.h>
 #include <linux/tty.h>
+#include <linux/mutex.h>
 #include <linux/idr.h>
 #include <linux/devpts_fs.h>
 #include <linux/parser.h>
@@ -29,7 +30,7 @@
 
 extern int pty_limit;			/* Config limit on Unix98 ptys */
 static DEFINE_IDR(allocated_ptys);
-static DECLARE_MUTEX(allocated_ptys_lock);
+static DEFINE_MUTEX(allocated_ptys_lock);
 
 static struct vfsmount *devpts_mnt;
 static struct dentry *devpts_root;
@@ -186,10 +187,10 @@ retry:
 		return -ENOMEM;
 	}
 
-	down(&allocated_ptys_lock);
+	mutex_lock(&allocated_ptys_lock);
 	idr_ret = idr_get_new(&allocated_ptys, NULL, &index);
 	if (idr_ret < 0) {
-		up(&allocated_ptys_lock);
+		mutex_unlock(&allocated_ptys_lock);
 		if (idr_ret == -EAGAIN)
 			goto retry;
 		return -EIO;
@@ -197,18 +198,18 @@ retry:
 
 	if (index >= pty_limit) {
 		idr_remove(&allocated_ptys, index);
-		up(&allocated_ptys_lock);
+		mutex_unlock(&allocated_ptys_lock);
 		return -EIO;
 	}
-	up(&allocated_ptys_lock);
+	mutex_unlock(&allocated_ptys_lock);
 	return index;
 }
 
 void devpts_kill_index(int idx)
 {
-	down(&allocated_ptys_lock);
+	mutex_lock(&allocated_ptys_lock);
 	idr_remove(&allocated_ptys, idx);
-	up(&allocated_ptys_lock);
+	mutex_unlock(&allocated_ptys_lock);
 }
 
 int devpts_pty_new(struct tty_struct *tty)
_

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Re: [PATCH]: Factor out PTY index allocation [message #29598 is a reply to message #29550] Thu, 17 April 2008 21:08 Go to previous messageGo to next message
Jiri Slaby is currently offline  Jiri Slaby
Messages: 2
Registered: December 2007
Junior Member
On 04/17/2008 12:17 AM, sukadev@us.ibm.com wrote:
> We noticed this while working on pts namespaces and believe this might
> be an useful change even as we rework our pts/device namespace approach.
> 
> ---
> 
> From: Sukadev Bhattiprolu <sukadev@us.ibm.com>
> Subject: [PATCH]: Factor out PTY index allocation
> 
> Factor out the code used to allocate/free a pts index into new interfaces,
> devpts_new_index() and devpts_kill_index().  This localizes the external
> data structures used in managing the pts indices.
> 
> Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
> Signed-off-by: Serge Hallyn<serue@us.ibm.com>
> Signed-off-by: Matt Helsley<matthltc@us.ibm.com>
> 
> ---
>  drivers/char/tty_io.c     |   40 ++++++----------------------------------
>  fs/devpts/inode.c         |   42 +++++++++++++++++++++++++++++++++++++++++-
>  include/linux/devpts_fs.h |    4 ++++
>  3 files changed, 51 insertions(+), 35 deletions(-)
[...]
> Index: 2.6.25-rc8-mm2/drivers/char/tty_io.c
> ===================================================================
> --- 2.6.25-rc8-mm2.orig/drivers/char/tty_io.c	2008-04-16 09:51:11.000000000 -0700
> +++ 2.6.25-rc8-mm2/drivers/char/tty_io.c	2008-04-16 09:51:15.000000000 -0700
> @@ -137,9 +136,6 @@ EXPORT_SYMBOL(tty_mutex);
>  
>  #ifdef CONFIG_UNIX98_PTYS
>  extern struct tty_driver *ptm_driver;	/* Unix98 pty masters; for /dev/ptmx */
> -extern int pty_limit;			/* Config limit on Unix98 ptys */
> -static DEFINE_IDR(allocated_ptys);
> -static DEFINE_MUTEX(allocated_ptys_lock);
[...]
> Index: 2.6.25-rc8-mm2/fs/devpts/inode.c
> ===================================================================
> --- 2.6.25-rc8-mm2.orig/fs/devpts/inode.c	2008-02-27 15:17:59.000000000 -0800
> +++ 2.6.25-rc8-mm2/fs/devpts/inode.c	2008-04-16 09:51:15.000000000 -0700
> @@ -26,6 +27,10 @@
>  
>  #define DEVPTS_DEFAULT_MODE 0600
>  
> +extern int pty_limit;			/* Config limit on Unix98 ptys */
> +static DEFINE_IDR(allocated_ptys);
> +static DECLARE_MUTEX(allocated_ptys_lock);

Ugh, why mutex->semaphore conversion?
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Re: [PATCH]: Factor out PTY index allocation [message #29599 is a reply to message #29597] Thu, 17 April 2008 23:53 Go to previous message
Matt Helsley is currently offline  Matt Helsley
Messages: 86
Registered: August 2006
Member
On Thu, 2008-04-17 at 14:17 -0700, Andrew Morton wrote:
> On Wed, 16 Apr 2008 15:17:23 -0700
> sukadev@us.ibm.com wrote:
> 
> > Factor out the code used to allocate/free a pts index into new interfaces,
> > devpts_new_index() and devpts_kill_index().  This localizes the external
> > data structures used in managing the pts indices.
> 
> err...
> 
> > -	mutex_lock(&allocated_ptys_lock);
> > +	down(&allocated_ptys_lock);
> 
> Why the mutex-to-semaphore conversion?

The patch series was originally developed for 2.6.22 -- prior to the
semaphore -> mutex migration. This appears to be a mistake in
forward-porting the series.

Acked-by: Matt Helsley <matthltc@us.ibm.com>

> 
> --- a/fs/devpts/inode.c~devpts-factor-out-pty-index-allocation-fix
> +++ a/fs/devpts/inode.c
> @@ -17,6 +17,7 @@
>  #include <linux/namei.h>
>  #include <linux/mount.h>
>  #include <linux/tty.h>
> +#include <linux/mutex.h>
>  #include <linux/idr.h>
>  #include <linux/devpts_fs.h>
>  #include <linux/parser.h>
> @@ -29,7 +30,7 @@
> 
>  extern int pty_limit;			/* Config limit on Unix98 ptys */
>  static DEFINE_IDR(allocated_ptys);
> -static DECLARE_MUTEX(allocated_ptys_lock);
> +static DEFINE_MUTEX(allocated_ptys_lock);
> 
>  static struct vfsmount *devpts_mnt;
>  static struct dentry *devpts_root;
> @@ -186,10 +187,10 @@ retry:
>  		return -ENOMEM;
>  	}
> 
> -	down(&allocated_ptys_lock);
> +	mutex_lock(&allocated_ptys_lock);
>  	idr_ret = idr_get_new(&allocated_ptys, NULL, &index);
>  	if (idr_ret < 0) {
> -		up(&allocated_ptys_lock);
> +		mutex_unlock(&allocated_ptys_lock);
>  		if (idr_ret == -EAGAIN)
>  			goto retry;
>  		return -EIO;
> @@ -197,18 +198,18 @@ retry:
> 
>  	if (index >= pty_limit) {
>  		idr_remove(&allocated_ptys, index);
> -		up(&allocated_ptys_lock);
> +		mutex_unlock(&allocated_ptys_lock);
>  		return -EIO;
>  	}
> -	up(&allocated_ptys_lock);
> +	mutex_unlock(&allocated_ptys_lock);
>  	return index;
>  }
> 
>  void devpts_kill_index(int idx)
>  {
> -	down(&allocated_ptys_lock);
> +	mutex_lock(&allocated_ptys_lock);
>  	idr_remove(&allocated_ptys, idx);
> -	up(&allocated_ptys_lock);
> +	mutex_unlock(&allocated_ptys_lock);
>  }
> 
>  int devpts_pty_new(struct tty_struct *tty)
> _
> 
> --
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