tty: Make tty_files_lock per-tty
Access to tty->tty_files list is always per-tty, never for all ttys
simultaneously. Replace global tty_files_lock spinlock with per-tty
->files_lock. Initialize when the ->tty_files list is inited, in
alloc_tty_struct().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index e8996fc..c5b4274 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -138,9 +138,6 @@
/* Mutex to protect creating and releasing a tty */
DEFINE_MUTEX(tty_mutex);
-/* Spinlock to protect the tty->tty_files list */
-DEFINE_SPINLOCK(tty_files_lock);
-
static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
ssize_t redirected_tty_write(struct file *, const char __user *,
@@ -202,9 +199,9 @@
priv->tty = tty;
priv->file = file;
- spin_lock(&tty_files_lock);
+ spin_lock(&tty->files_lock);
list_add(&priv->list, &tty->tty_files);
- spin_unlock(&tty_files_lock);
+ spin_unlock(&tty->files_lock);
}
/**
@@ -225,10 +222,11 @@
static void tty_del_file(struct file *file)
{
struct tty_file_private *priv = file->private_data;
+ struct tty_struct *tty = priv->tty;
- spin_lock(&tty_files_lock);
+ spin_lock(&tty->files_lock);
list_del(&priv->list);
- spin_unlock(&tty_files_lock);
+ spin_unlock(&tty->files_lock);
tty_free_file(file);
}
@@ -286,11 +284,11 @@
struct list_head *p;
int count = 0;
- spin_lock(&tty_files_lock);
+ spin_lock(&tty->files_lock);
list_for_each(p, &tty->tty_files) {
count++;
}
- spin_unlock(&tty_files_lock);
+ spin_unlock(&tty->files_lock);
if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
tty->driver->subtype == PTY_TYPE_SLAVE &&
tty->link && tty->link->count)
@@ -713,7 +711,7 @@
workqueue with the lock held */
check_tty_count(tty, "tty_hangup");
- spin_lock(&tty_files_lock);
+ spin_lock(&tty->files_lock);
/* This breaks for file handles being sent over AF_UNIX sockets ? */
list_for_each_entry(priv, &tty->tty_files, list) {
filp = priv->file;
@@ -725,7 +723,7 @@
__tty_fasync(-1, filp, 0); /* can't block */
filp->f_op = &hung_up_tty_fops;
}
- spin_unlock(&tty_files_lock);
+ spin_unlock(&tty->files_lock);
refs = tty_signal_session_leader(tty, exit_session);
/* Account for the p->signal references we killed */
@@ -1637,9 +1635,9 @@
tty_driver_kref_put(driver);
module_put(owner);
- spin_lock(&tty_files_lock);
+ spin_lock(&tty->files_lock);
list_del_init(&tty->tty_files);
- spin_unlock(&tty_files_lock);
+ spin_unlock(&tty->files_lock);
put_pid(tty->pgrp);
put_pid(tty->session);
@@ -3176,6 +3174,7 @@
mutex_init(&tty->atomic_write_lock);
spin_lock_init(&tty->ctrl_lock);
spin_lock_init(&tty->flow_lock);
+ spin_lock_init(&tty->files_lock);
INIT_LIST_HEAD(&tty->tty_files);
INIT_WORK(&tty->SAK_work, do_SAK_work);