Add an instance parameter devpts interfaces

Pass-in 'inode' or 'tty' parameter to devpts interfaces.  With multiple
devpts instances, these parameters will be used in subsequent patches
to identify the instance of devpts mounted. The parameters also help
simplify devpts implementation.

Changelog[v3]:
	- minor changes due to merge with ttydev updates
	- rename parameters to emphasize they are ptmx or pts inodes
	- pass-in tty_struct * to devpts_pty_kill() (this will help
	  cleanup the get_node() call in a subsequent patch)

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 18 insertions, 14 deletions

diff --git a/drivers/char/pty.c b/drivers/char/pty.c
index c5a192dd00d..a391badef52 100644
--- a/drivers/char/pty.c
+++ b/drivers/char/pty.c
@@ -60,7 +60,7 @@ static void pty_close(struct tty_struct * tty, struct file * filp)
                 set_bit(TTY_OTHER_CLOSED, &tty->flags);
 #ifdef CONFIG_UNIX98_PTYS
                 if (tty->driver == ptm_driver)
-                        devpts_pty_kill(tty->index);
+                        devpts_pty_kill(tty->link);
 #endif
                 tty_vhangup(tty->link);
         }
@@ -453,9 +453,10 @@ static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
  *      This provides our locking.
  */
 
-static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver, int idx)
+static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
+                struct inode *ptm_inode, int idx)
 {
-        struct tty_struct *tty = devpts_get_tty(idx);
+        struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
         if (tty)
                 tty = tty->link;
         return tty;
@@ -470,9 +471,10 @@ static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver, int idx)
  *      This provides our locking.
  */
 
-static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, int idx)
+static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
+                struct inode *pts_inode, int idx)
 {
-        struct tty_struct *tty = devpts_get_tty(idx);
+        struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
         /* Master must be open before slave */
         if (!tty)
                 return ERR_PTR(-EIO);
@@ -602,7 +604,7 @@ static int __ptmx_open(struct inode *inode, struct file *filp)
         nonseekable_open(inode, filp);
 
         /* find a device that is not in use. */
-        index = devpts_new_index();
+        index = devpts_new_index(inode);
         if (index < 0)
                 return index;
 
@@ -619,7 +621,7 @@ static int __ptmx_open(struct inode *inode, struct file *filp)
         filp->private_data = tty;
         file_move(filp, &tty->tty_files);
 
-        retval = devpts_pty_new(tty->link);
+        retval = devpts_pty_new(inode, tty->link);
         if (retval)
                 goto out1;
 
@@ -630,7 +632,7 @@ out1:
         tty_release_dev(filp);
         return retval;
 out:
-        devpts_kill_index(index);
+        devpts_kill_index(inode, index);
         return retval;
 }
 
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 36098ee8fe6..95908396102 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1213,12 +1213,13 @@ static void tty_line_name(struct tty_driver *driver, int index, char *p)
  *      be held until the 'fast-open' is also done. Will change once we
  *      have refcounting in the driver and per driver locking
  */
-struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver, int idx)
+struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
+                struct inode *inode, int idx)
 {
         struct tty_struct *tty;
 
         if (driver->ops->lookup)
-                return driver->ops->lookup(driver, idx);
+                return driver->ops->lookup(driver, inode, idx);
 
         tty = driver->ttys[idx];
         return tty;
@@ -1539,10 +1540,11 @@ void tty_release_dev(struct file *filp)
         int     devpts;
         int     idx;
         char    buf[64];
+        struct  inode *inode;
 
+        inode = filp->f_path.dentry->d_inode;
         tty = (struct tty_struct *)filp->private_data;
-        if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode,
-                                                        "tty_release_dev"))
+        if (tty_paranoia_check(tty, inode, "tty_release_dev"))
                 return;
 
         check_tty_count(tty, "tty_release_dev");
@@ -1751,7 +1753,7 @@ void tty_release_dev(struct file *filp)
 
         /* Make this pty number available for reallocation */
         if (devpts)
-                devpts_kill_index(idx);
+                devpts_kill_index(inode, idx);
 }
 
 /**
@@ -1836,7 +1838,7 @@ retry_open:
 got_driver:
         if (!tty) {
                 /* check whether we're reopening an existing tty */
-                tty = tty_driver_lookup_tty(driver, index);
+                tty = tty_driver_lookup_tty(driver, inode, index);
 
                 if (IS_ERR(tty))
                         return PTR_ERR(tty);