tty: push the BKL down into the handlers a bit
Start trying to untangle the remaining BKL mess
Updated to fix missing unlock_kernel noted by Dan Carpenter
Signed-off-by: Alan "I must be out of my tree" Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 59499ee..1e24130 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -142,7 +142,6 @@
size_t, loff_t *);
static unsigned int tty_poll(struct file *, poll_table *);
static int tty_open(struct inode *, struct file *);
-static int tty_release(struct inode *, struct file *);
long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
#ifdef CONFIG_COMPAT
static long tty_compat_ioctl(struct file *file, unsigned int cmd,
@@ -1017,14 +1016,16 @@
void tty_write_message(struct tty_struct *tty, char *msg)
{
- lock_kernel();
if (tty) {
mutex_lock(&tty->atomic_write_lock);
- if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags))
+ lock_kernel();
+ if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
+ unlock_kernel();
tty->ops->write(tty, msg, strlen(msg));
+ } else
+ unlock_kernel();
tty_write_unlock(tty);
}
- unlock_kernel();
return;
}
@@ -1202,14 +1203,21 @@
struct tty_struct *tty)
{
int idx = tty->index;
+ int ret;
- if (driver->ops->install)
- return driver->ops->install(driver, tty);
+ if (driver->ops->install) {
+ lock_kernel();
+ ret = driver->ops->install(driver, tty);
+ unlock_kernel();
+ return ret;
+ }
if (tty_init_termios(tty) == 0) {
+ lock_kernel();
tty_driver_kref_get(driver);
tty->count++;
driver->ttys[idx] = tty;
+ unlock_kernel();
return 0;
}
return -ENOMEM;
@@ -1302,10 +1310,14 @@
struct tty_struct *tty;
int retval;
+ lock_kernel();
/* Check if pty master is being opened multiple times */
if (driver->subtype == PTY_TYPE_MASTER &&
- (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok)
+ (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
+ unlock_kernel();
return ERR_PTR(-EIO);
+ }
+ unlock_kernel();
/*
* First time open is complex, especially for PTY devices.
@@ -1335,8 +1347,9 @@
* If we fail here just call release_tty to clean up. No need
* to decrement the use counts, as release_tty doesn't care.
*/
-
+ lock_kernel();
retval = tty_ldisc_setup(tty, tty->link);
+ unlock_kernel();
if (retval)
goto release_mem_out;
return tty;
@@ -1350,7 +1363,9 @@
if (printk_ratelimit())
printk(KERN_INFO "tty_init_dev: ldisc open failed, "
"clearing slot %d\n", idx);
+ lock_kernel();
release_tty(tty, idx);
+ unlock_kernel();
return ERR_PTR(retval);
}
@@ -1464,7 +1479,17 @@
tty_kref_put(tty);
}
-/*
+/**
+ * tty_release - vfs callback for close
+ * @inode: inode of tty
+ * @filp: file pointer for handle to tty
+ *
+ * Called the last time each file handle is closed that references
+ * this tty. There may however be several such references.
+ *
+ * Locking:
+ * Takes bkl. See tty_release_dev
+ *
* Even releasing the tty structures is a tricky business.. We have
* to be very careful that the structures are all released at the
* same time, as interrupts might otherwise get the wrong pointers.
@@ -1472,20 +1497,20 @@
* WSH 09/09/97: rewritten to avoid some nasty race conditions that could
* lead to double frees or releasing memory still in use.
*/
-void tty_release_dev(struct file *filp)
+
+int tty_release(struct inode *inode, struct file *filp)
{
struct tty_struct *tty, *o_tty;
int pty_master, tty_closing, o_tty_closing, do_sleep;
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, inode, "tty_release_dev"))
- return;
+ return 0;
+ lock_kernel();
check_tty_count(tty, "tty_release_dev");
tty_fasync(-1, filp, 0);
@@ -1500,19 +1525,22 @@
if (idx < 0 || idx >= tty->driver->num) {
printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
"free (%s)\n", tty->name);
- return;
+ unlock_kernel();
+ return 0;
}
if (!devpts) {
if (tty != tty->driver->ttys[idx]) {
+ unlock_kernel();
printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
"for (%s)\n", idx, tty->name);
- return;
+ return 0;
}
if (tty->termios != tty->driver->termios[idx]) {
+ unlock_kernel();
printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
"for (%s)\n",
idx, tty->name);
- return;
+ return 0;
}
}
#endif
@@ -1526,26 +1554,30 @@
if (tty->driver->other &&
!(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
if (o_tty != tty->driver->other->ttys[idx]) {
+ unlock_kernel();
printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
"not o_tty for (%s)\n",
idx, tty->name);
- return;
+ return 0 ;
}
if (o_tty->termios != tty->driver->other->termios[idx]) {
+ unlock_kernel();
printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
"not o_termios for (%s)\n",
idx, tty->name);
- return;
+ return 0;
}
if (o_tty->link != tty) {
+ unlock_kernel();
printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
- return;
+ return 0;
}
}
#endif
if (tty->ops->close)
tty->ops->close(tty, filp);
+ unlock_kernel();
/*
* Sanity check: if tty->count is going to zero, there shouldn't be
* any waiters on tty->read_wait or tty->write_wait. We test the
@@ -1568,6 +1600,7 @@
opens on /dev/tty */
mutex_lock(&tty_mutex);
+ lock_kernel();
tty_closing = tty->count <= 1;
o_tty_closing = o_tty &&
(o_tty->count <= (pty_master ? 1 : 0));
@@ -1598,6 +1631,7 @@
printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
"active!\n", tty_name(tty, buf));
+ unlock_kernel();
mutex_unlock(&tty_mutex);
schedule();
}
@@ -1661,8 +1695,10 @@
mutex_unlock(&tty_mutex);
/* check whether both sides are closing ... */
- if (!tty_closing || (o_tty && !o_tty_closing))
- return;
+ if (!tty_closing || (o_tty && !o_tty_closing)) {
+ unlock_kernel();
+ return 0;
+ }
#ifdef TTY_DEBUG_HANGUP
printk(KERN_DEBUG "freeing tty structure...");
@@ -1680,10 +1716,12 @@
/* Make this pty number available for reallocation */
if (devpts)
devpts_kill_index(inode, idx);
+ unlock_kernel();
+ return 0;
}
/**
- * __tty_open - open a tty device
+ * tty_open - open a tty device
* @inode: inode of device file
* @filp: file pointer to tty
*
@@ -1703,7 +1741,7 @@
* ->siglock protects ->signal/->sighand
*/
-static int __tty_open(struct inode *inode, struct file *filp)
+static int tty_open(struct inode *inode, struct file *filp)
{
struct tty_struct *tty = NULL;
int noctty, retval;
@@ -1720,10 +1758,12 @@
retval = 0;
mutex_lock(&tty_mutex);
+ lock_kernel();
if (device == MKDEV(TTYAUX_MAJOR, 0)) {
tty = get_current_tty();
if (!tty) {
+ unlock_kernel();
mutex_unlock(&tty_mutex);
return -ENXIO;
}
@@ -1755,12 +1795,14 @@
goto got_driver;
}
}
+ unlock_kernel();
mutex_unlock(&tty_mutex);
return -ENODEV;
}
driver = get_tty_driver(device, &index);
if (!driver) {
+ unlock_kernel();
mutex_unlock(&tty_mutex);
return -ENODEV;
}
@@ -1770,6 +1812,7 @@
tty = tty_driver_lookup_tty(driver, inode, index);
if (IS_ERR(tty)) {
+ unlock_kernel();
mutex_unlock(&tty_mutex);
return PTR_ERR(tty);
}
@@ -1784,8 +1827,10 @@
mutex_unlock(&tty_mutex);
tty_driver_kref_put(driver);
- if (IS_ERR(tty))
+ if (IS_ERR(tty)) {
+ unlock_kernel();
return PTR_ERR(tty);
+ }
filp->private_data = tty;
file_move(filp, &tty->tty_files);
@@ -1813,11 +1858,15 @@
printk(KERN_DEBUG "error %d in opening %s...", retval,
tty->name);
#endif
- tty_release_dev(filp);
- if (retval != -ERESTARTSYS)
+ tty_release(inode, filp);
+ if (retval != -ERESTARTSYS) {
+ unlock_kernel();
return retval;
- if (signal_pending(current))
+ }
+ if (signal_pending(current)) {
+ unlock_kernel();
return retval;
+ }
schedule();
/*
* Need to reset f_op in case a hangup happened.
@@ -1826,8 +1875,11 @@
filp->f_op = &tty_fops;
goto retry_open;
}
+ unlock_kernel();
+
mutex_lock(&tty_mutex);
+ lock_kernel();
spin_lock_irq(¤t->sighand->siglock);
if (!noctty &&
current->signal->leader &&
@@ -1835,43 +1887,12 @@
tty->session == NULL)
__proc_set_tty(current, tty);
spin_unlock_irq(¤t->sighand->siglock);
+ unlock_kernel();
mutex_unlock(&tty_mutex);
return 0;
}
-/* BKL pushdown: scary code avoidance wrapper */
-static int tty_open(struct inode *inode, struct file *filp)
-{
- int ret;
- lock_kernel();
- ret = __tty_open(inode, filp);
- unlock_kernel();
- return ret;
-}
-
-
-
-
-/**
- * tty_release - vfs callback for close
- * @inode: inode of tty
- * @filp: file pointer for handle to tty
- *
- * Called the last time each file handle is closed that references
- * this tty. There may however be several such references.
- *
- * Locking:
- * Takes bkl. See tty_release_dev
- */
-
-static int tty_release(struct inode *inode, struct file *filp)
-{
- lock_kernel();
- tty_release_dev(filp);
- unlock_kernel();
- return 0;
-}
/**
* tty_poll - check tty status
@@ -2317,9 +2338,7 @@
if (get_user(ldisc, p))
return -EFAULT;
- lock_kernel();
ret = tty_set_ldisc(tty, ldisc);
- unlock_kernel();
return ret;
}