---
25-akpm/drivers/char/tty_io.c | 57 ++++++++++++++++++++++++++++++++++--------
1 files changed, 47 insertions(+), 10 deletions(-)
diff -puN drivers/char/tty_io.c~pty-allocation-first-fit drivers/char/tty_io.c
--- 25/drivers/char/tty_io.c~pty-allocation-first-fit 2004-05-17 18:28:49.621270672 -0700
+++ 25-akpm/drivers/char/tty_io.c 2004-05-17 18:33:02.903765880 -0700
@@ -91,6 +91,7 @@
#include <linux/module.h>
#include <linux/smp_lock.h>
#include <linux/device.h>
+#include <linux/idr.h>
#include <asm/uaccess.h>
#include <asm/system.h>
@@ -128,6 +129,8 @@ DECLARE_MUTEX(tty_sem);
#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 DECLARE_MUTEX(allocated_ptys_lock);
#endif
extern void disable_early_printk(void);
@@ -1295,6 +1298,14 @@ static void release_dev(struct file * fi
o_tty->ldisc = ldiscs[N_TTY];
}
+#ifdef CONFIG_UNIX98_PTYS
+ if (filp->f_dentry->d_inode->i_rdev == MKDEV(TTYAUX_MAJOR,2)) {
+ down(&allocated_ptys_lock);
+ idr_remove(&allocated_ptys, idx);
+ up(&allocated_ptys_lock);
+ }
+#endif
+
/*
* The release_mem function takes care of the details of clearing
* the slots and preserving the termios structure.
@@ -1319,7 +1330,7 @@ static int tty_open(struct inode * inode
struct tty_struct *tty;
int noctty, retval;
struct tty_driver *driver;
- int index;
+ int index = -1;
dev_t device = inode->i_rdev;
unsigned short saved_flags = filp->f_flags;
retry_open:
@@ -1361,23 +1372,41 @@ retry_open:
#ifdef CONFIG_UNIX98_PTYS
if (device == MKDEV(TTYAUX_MAJOR,2)) {
+ int idr_ret;
+
/* find a device that is not in use. */
- static int next_ptmx_dev = 0;
- retval = -1;
+ down(&allocated_ptys_lock);
+ if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) {
+ up(&allocated_ptys_lock);
+ return -ENOMEM;
+ }
+ idr_ret = idr_get_new(&allocated_ptys, NULL, &index);
+ if (idr_ret < 0) {
+ up(&allocated_ptys_lock);
+ if (idr_ret == -EAGAIN)
+ return -ENOMEM;
+ return -EIO;
+ }
+ if (index >= pty_limit) {
+ idr_remove(&allocated_ptys, index);
+ up(&allocated_ptys_lock);
+ return -EIO;
+ }
driver = ptm_driver;
- while (driver->refcount < pty_limit) {
- index = next_ptmx_dev;
- next_ptmx_dev = (next_ptmx_dev+1) % driver->num;
- if (!init_dev(driver, index, &tty))
- goto ptmx_found; /* ok! */
+ retval = init_dev(driver, index, &tty);
+ if (retval) {
+ idr_remove(&allocated_ptys, index);
+ up(&allocated_ptys_lock);
+ return retval;
}
- return -EIO; /* no free ptys */
- ptmx_found:
set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
if (devpts_pty_new(tty->link)) {
/* BADNESS - need to destroy both ptm and pts! */
+ idr_remove(&allocated_ptys, index);
+ up(&allocated_ptys_lock);
return -ENOMEM;
}
+ up(&allocated_ptys_lock);
noctty = 1;
} else
#endif
@@ -1415,6 +1444,14 @@ got_driver:
tty->name);
#endif
+#ifdef CONFIG_UNIX98_PTYS
+ if (index != -1) {
+ down(&allocated_ptys_lock);
+ idr_remove(&allocated_ptys, index);
+ up(&allocated_ptys_lock);
+ }
+#endif
+
release_dev(filp);
if (retval != -ERESTARTSYS)
return retval;
_