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Revert "tty: tty_port: add workqueue to flip TTY buffer"

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This reverts commit d000422a46.

It is reported by many to cause boot failures, so must be reverted.

Cc: Xin Zhao <jackzxcui1989@163.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/d1942304-ee30-478d-90fb-279519f3ae81@samsung.com
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reported-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Greg Kroah-Hartman 2026-01-27 13:58:21 +01:00
parent d000422a46
commit 0a15f43b92
7 changed files with 9 additions and 78 deletions
Download patch file Download diff file Expand all files Collapse all files

14
drivers/tty/pty.c
View file

@ -403,8 +403,6 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
o_tty->link = tty;
tty_port_init(ports[0]);
tty_port_init(ports[1]);
tty_port_link_wq(ports[0], system_dfl_wq);
tty_port_link_wq(ports[1], system_dfl_wq);
tty_buffer_set_limit(ports[0], 8192);
tty_buffer_set_limit(ports[1], 8192);
o_tty->port = ports[0];
@ -534,16 +532,14 @@ static void __init legacy_pty_init(void)
pty_driver = tty_alloc_driver(legacy_count,
TTY_DRIVER_RESET_TERMIOS |
TTY_DRIVER_REAL_RAW |
TTY_DRIVER_DYNAMIC_ALLOC |
TTY_DRIVER_CUSTOM_WORKQUEUE);
TTY_DRIVER_DYNAMIC_ALLOC);
if (IS_ERR(pty_driver))
panic("Couldn't allocate pty driver");
pty_slave_driver = tty_alloc_driver(legacy_count,
TTY_DRIVER_RESET_TERMIOS |
TTY_DRIVER_REAL_RAW |
TTY_DRIVER_DYNAMIC_ALLOC |
TTY_DRIVER_CUSTOM_WORKQUEUE);
TTY_DRIVER_DYNAMIC_ALLOC);
if (IS_ERR(pty_slave_driver))
panic("Couldn't allocate pty slave driver");
@ -853,8 +849,7 @@ static void __init unix98_pty_init(void)
TTY_DRIVER_REAL_RAW |
TTY_DRIVER_DYNAMIC_DEV |
TTY_DRIVER_DEVPTS_MEM |
TTY_DRIVER_DYNAMIC_ALLOC |
TTY_DRIVER_CUSTOM_WORKQUEUE);
TTY_DRIVER_DYNAMIC_ALLOC);
if (IS_ERR(ptm_driver))
panic("Couldn't allocate Unix98 ptm driver");
pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
@ -862,8 +857,7 @@ static void __init unix98_pty_init(void)
TTY_DRIVER_REAL_RAW |
TTY_DRIVER_DYNAMIC_DEV |
TTY_DRIVER_DEVPTS_MEM |
TTY_DRIVER_DYNAMIC_ALLOC |
TTY_DRIVER_CUSTOM_WORKQUEUE);
TTY_DRIVER_DYNAMIC_ALLOC);
if (IS_ERR(pts_driver))
panic("Couldn't allocate Unix98 pts driver");

8
drivers/tty/tty_buffer.c
View file

@ -76,7 +76,7 @@ void tty_buffer_unlock_exclusive(struct tty_port *port)
mutex_unlock(&buf->lock);
if (restart)
queue_work(buf->flip_wq, &buf->work);
queue_work(system_dfl_wq, &buf->work);
}
EXPORT_SYMBOL_GPL(tty_buffer_unlock_exclusive);
@ -530,7 +530,7 @@ void tty_flip_buffer_push(struct tty_port *port)
struct tty_bufhead *buf = &port->buf;
tty_flip_buffer_commit(buf->tail);
queue_work(buf->flip_wq, &buf->work);
queue_work(system_dfl_wq, &buf->work);
}
EXPORT_SYMBOL(tty_flip_buffer_push);
@ -560,7 +560,7 @@ int tty_insert_flip_string_and_push_buffer(struct tty_port *port,
tty_flip_buffer_commit(buf->tail);
spin_unlock_irqrestore(&port->lock, flags);
queue_work(buf->flip_wq, &buf->work);
queue_work(system_dfl_wq, &buf->work);
return size;
}
@ -613,7 +613,7 @@ void tty_buffer_set_lock_subclass(struct tty_port *port)
bool tty_buffer_restart_work(struct tty_port *port)
{
return queue_work(port->buf.flip_wq, &port->buf.work);
return queue_work(system_dfl_wq, &port->buf.work);
}
bool tty_buffer_cancel_work(struct tty_port *port)

21
drivers/tty/tty_io.c
View file

@ -3446,23 +3446,10 @@ int tty_register_driver(struct tty_driver *driver)
if (error < 0)
goto err;
if (!(driver->flags & TTY_DRIVER_CUSTOM_WORKQUEUE)) {
driver->flip_wq = alloc_workqueue("%s-flip-wq", WQ_UNBOUND | WQ_SYSFS,
0, driver->name);
if (!driver->flip_wq) {
error = -ENOMEM;
goto err_unreg_char;
}
for (i = 0; i < driver->num; i++) {
if (driver->ports[i])
tty_port_link_driver_wq(driver->ports[i], driver);
}
}
if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
error = tty_cdev_add(driver, dev, 0, driver->num);
if (error)
goto err_destroy_wq;
goto err_unreg_char;
}
scoped_guard(mutex, &tty_mutex)
@ -3488,10 +3475,6 @@ err_unreg_devs:
scoped_guard(mutex, &tty_mutex)
list_del(&driver->tty_drivers);
err_destroy_wq:
if (!(driver->flags & TTY_DRIVER_CUSTOM_WORKQUEUE))
destroy_workqueue(driver->flip_wq);
err_unreg_char:
unregister_chrdev_region(dev, driver->num);
err:
@ -3511,8 +3494,6 @@ void tty_unregister_driver(struct tty_driver *driver)
driver->num);
scoped_guard(mutex, &tty_mutex)
list_del(&driver->tty_drivers);
if (!(driver->flags & TTY_DRIVER_CUSTOM_WORKQUEUE))
destroy_workqueue(driver->flip_wq);
}
EXPORT_SYMBOL(tty_unregister_driver);

23
drivers/tty/tty_port.c
View file

@ -99,26 +99,6 @@ void tty_port_init(struct tty_port *port)
}
EXPORT_SYMBOL(tty_port_init);
/**
* tty_port_link_wq - link tty_port and flip workqueue
* @port: tty_port of the device
* @flip_wq: workqueue to queue flip buffer work on
*
* When %TTY_DRIVER_CUSTOM_WORKQUEUE is used, every tty_port shall be linked to
* a workqueue manually by this function, otherwise tty_flip_buffer_push() will
* see %NULL flip_wq pointer on queue_work.
* When %TTY_DRIVER_CUSTOM_WORKQUEUE is NOT used, the function can be used to
* link a certain port to a specific workqueue, instead of using the workqueue
* allocated in tty_register_driver().
*
* Note that TTY port API will NOT destroy the workqueue.
*/
void tty_port_link_wq(struct tty_port *port, struct workqueue_struct *flip_wq)
{
port->buf.flip_wq = flip_wq;
}
EXPORT_SYMBOL_GPL(tty_port_link_wq);
/**
* tty_port_link_device - link tty and tty_port
* @port: tty_port of the device
@ -177,7 +157,6 @@ struct device *tty_port_register_device_attr(struct tty_port *port,
const struct attribute_group **attr_grp)
{
tty_port_link_device(port, driver, index);
tty_port_link_driver_wq(port, driver);
return tty_register_device_attr(driver, index, device, drvdata,
attr_grp);
}
@ -204,7 +183,6 @@ struct device *tty_port_register_device_attr_serdev(struct tty_port *port,
struct device *dev;
tty_port_link_device(port, driver, index);
tty_port_link_driver_wq(port, driver);
dev = serdev_tty_port_register(port, host, parent, driver, index);
if (PTR_ERR(dev) != -ENODEV) {
@ -725,7 +703,6 @@ int tty_port_install(struct tty_port *port, struct tty_driver *driver,
struct tty_struct *tty)
{
tty->port = port;
tty_port_link_driver_wq(port, driver);
return tty_standard_install(driver, tty);
}
EXPORT_SYMBOL_GPL(tty_port_install);

1
include/linux/tty_buffer.h
View file

@ -34,7 +34,6 @@ static inline u8 *flag_buf_ptr(struct tty_buffer *b, unsigned int ofs)
struct tty_bufhead {
struct tty_buffer *head; /* Queue head */
struct workqueue_struct *flip_wq;
struct work_struct work;
struct mutex lock;
atomic_t priority;

7
include/linux/tty_driver.h
View file

@ -69,10 +69,6 @@ struct serial_struct;
* Do not create numbered ``/dev`` nodes. For example, create
* ``/dev/ttyprintk`` and not ``/dev/ttyprintk0``. Applicable only when a
* driver for a single tty device is being allocated.
*
* @TTY_DRIVER_CUSTOM_WORKQUEUE:
* Do not create workqueue when tty_register_driver(). When set, flip
* buffer workqueue shall be set by tty_port_link_wq() for every port.
*/
enum tty_driver_flag {
TTY_DRIVER_INSTALLED = BIT(0),
@ -83,7 +79,6 @@ enum tty_driver_flag {
TTY_DRIVER_HARDWARE_BREAK = BIT(5),
TTY_DRIVER_DYNAMIC_ALLOC = BIT(6),
TTY_DRIVER_UNNUMBERED_NODE = BIT(7),
TTY_DRIVER_CUSTOM_WORKQUEUE = BIT(8),
};
enum tty_driver_type {
@ -511,7 +506,6 @@ struct tty_operations {
* @flags: tty driver flags (%TTY_DRIVER_)
* @proc_entry: proc fs entry, used internally
* @other: driver of the linked tty; only used for the PTY driver
* @flip_wq: workqueue to queue flip buffer work on
* @ttys: array of active &struct tty_struct, set by tty_standard_install()
* @ports: array of &struct tty_port; can be set during initialization by
* tty_port_link_device() and similar
@ -545,7 +539,6 @@ struct tty_driver {
unsigned long flags;
struct proc_dir_entry *proc_entry;
struct tty_driver *other;
struct workqueue_struct *flip_wq;
/*
* Pointer to the tty data structures

13
include/linux/tty_port.h
View file

@ -138,7 +138,6 @@ struct tty_port {
kernel */
void tty_port_init(struct tty_port *port);
void tty_port_link_wq(struct tty_port *port, struct workqueue_struct *flip_wq);
void tty_port_link_device(struct tty_port *port, struct tty_driver *driver,
unsigned index);
struct device *tty_port_register_device(struct tty_port *port,
@ -166,18 +165,6 @@ static inline struct tty_port *tty_port_get(struct tty_port *port)
return NULL;
}
/*
* Never overwrite the workqueue set by tty_port_link_wq().
* No effect when %TTY_DRIVER_CUSTOM_WORKQUEUE is set, as driver->flip_wq is
* %NULL.
*/
static inline void tty_port_link_driver_wq(struct tty_port *port,
struct tty_driver *driver)
{
if (!port->buf.flip_wq)
port->buf.flip_wq = driver->flip_wq;
}
/* If the cts flow control is enabled, return true. */
static inline bool tty_port_cts_enabled(const struct tty_port *port)
{