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

This reverts commit d000422a46aad32217cf1be747eb61d641baae2f.

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>

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 1f17575f8fe0c53de88791de6fb8aacec0ed6ef9..6120d827a797747233859ec740e89a6b8634930b 100644 (file)
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -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");
 

diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 86e1e7178e9001dda2f94be7c83d164d291aa1a6..1a5673acd9b107d55623defcfc1dadb853781274 100644 (file)
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -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)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index d64fb08baa179cfd63bd10ba6e624f2f5d41d43f..e2d92cf70eb78ec6b2b93b55192e46781160c9dc 100644 (file)
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -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);
 

diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 611f878149f8a0eb052e7c8814d4044287aab0de..fe67c5cb0a3f0c36c0581b44ea21ba858e8a2c4d 100644 (file)
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -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);

diff --git a/include/linux/tty_buffer.h b/include/linux/tty_buffer.h
index 48adcb0e8ff390c8b8f20292c05ca8262d87b95c..31125e3be3c55e4e65dd62d91fd13e96a91e6c27 100644 (file)
--- a/include/linux/tty_buffer.h
+++ b/include/linux/tty_buffer.h
@@ -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;

diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 9c65854f7d94e729e1d95f99ba75c5c1cf2ccd66..188ee9b768eb6d928c3c5ae2fd1811755c529e62 100644 (file)
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -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

diff --git a/include/linux/tty_port.h b/include/linux/tty_port.h
index c1b87f3c56034a5ec801eede1660a7998757b486..660c254f1efe5f61f41244f2bb8cfa6bec5f4849 100644 (file)
--- a/include/linux/tty_port.h
+++ b/include/linux/tty_port.h
@@ -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)
 {