From 4a510969374ab8853451c337e43d28fb864e43fd Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sat, 9 Jan 2016 21:35:23 -0800 Subject: 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 Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_io.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) (limited to 'drivers/tty/tty_io.c') diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index e8996fc3ff1c..c5b4274584dc 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -138,9 +138,6 @@ LIST_HEAD(tty_drivers); /* linked list of tty drivers */ /* 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 @@ void tty_add_file(struct tty_struct *tty, struct file *file) 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 @@ void tty_free_file(struct file *file) 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 @@ static int check_tty_count(struct tty_struct *tty, const char *routine) 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 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session) 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 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session) __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 @@ static void release_one_tty(struct work_struct *work) 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 @@ struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx) 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); -- cgit v1.2.3