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authorPeter Hurley <peter@hurleysoftware.com>2016-01-10 08:35:23 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-01-28 02:13:28 +0300
commit4a510969374ab8853451c337e43d28fb864e43fd (patch)
tree7868ef29c68bd7265dcf6fe5b2ab4088abeb7842 /drivers/tty/tty_io.c
parent527ffc11e1c0aa049b3a831d6f07ed98e06a0819 (diff)
downloadlinux-4a510969374ab8853451c337e43d28fb864e43fd.tar.xz
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>
Diffstat (limited to 'drivers/tty/tty_io.c')
-rw-r--r--drivers/tty/tty_io.c25
1 files changed, 12 insertions, 13 deletions
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);