mobile-nixos/devices/google-marlin/kernel/0001-Revert-four-tty-related-commits.patch

From fa9724dd4b960acfd60643a02ba45e764522f964 Mon Sep 17 00:00:00 2001
From: Daniel Fullmer <danielrf12@gmail.com>
Date: Sat, 23 Nov 2019 20:37:08 -0500
Subject: [PATCH] Revert four tty-related commits

With these commits, CONFIG_VT fails to boot on google-marlin, with no
serial port output.

These commits were found by matching the commit messages of samueldr's
reverts for google-walleye with the corresponding commits in
google-marlin.

Revert "tty:  check before stopping kthread"

This reverts commit abac1caf3e8b6a479a5db31b2f52b1187b41d520.

Revert "tty: move tty_port workqueue to be a kthread"

This reverts commit 1bb88fcb4961166195e2cb1973901ecf931983a1.

Revert "tty: add tty_port_set_policy function"

This reverts commit 2074f5b7c3b6b00d8ed80738f4c9169a1599fc5a.

Revert "msm_serial_hs:  make the Bluetooth tty thread RT"

This reverts commit 89f0850619a154520827a3f22300d095a977f494.
---
 drivers/tty/n_tty.c                |  2 +-
 drivers/tty/serial/msm_serial_hs.c |  2 --
 drivers/tty/tty_buffer.c           | 27 ++++++---------------------
 drivers/tty/tty_io.c               |  2 +-
 drivers/tty/tty_ldisc.c            |  5 ++---
 drivers/tty/tty_port.c             | 12 +-----------
 include/linux/tty.h                |  7 +------
 7 files changed, 12 insertions(+), 45 deletions(-)

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 1f2e6130cb4..118466d539b 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -244,7 +244,7 @@ static void n_tty_set_room(struct tty_struct *tty)
 		 */
 		WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags),
 			       "scheduling buffer work for halted ldisc\n");
-		queue_kthread_work(&tty->port->worker, &tty->port->buf.work);
+		queue_work(system_unbound_wq, &tty->port->buf.work);
 	}
 }
 
diff --git a/drivers/tty/serial/msm_serial_hs.c b/drivers/tty/serial/msm_serial_hs.c
index efc7e1be154..f8f28d0b1f9 100644
--- a/drivers/tty/serial/msm_serial_hs.c
+++ b/drivers/tty/serial/msm_serial_hs.c
@@ -61,7 +61,6 @@
 #include <linux/ipc_logging.h>
 #include <asm/irq.h>
 #include <linux/kthread.h>
-#include <uapi/linux/sched.h>
 
 #include <linux/msm-sps.h>
 #include <linux/platform_data/msm_serial_hs.h>
@@ -3288,7 +3287,6 @@ static void  msm_serial_hs_rt_init(struct uart_port *uport)
 	msm_uport->pm_state = MSM_HS_PM_SUSPENDED;
 	mutex_unlock(&msm_uport->mtx);
 	pm_runtime_enable(uport->dev);
-	tty_port_set_policy(&uport->state->port, SCHED_FIFO, 1);
 }
 
 static int msm_hs_runtime_suspend(struct device *dev)
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 157d43500da..8a7655166ad 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -72,7 +72,7 @@ void tty_buffer_unlock_exclusive(struct tty_port *port)
 	atomic_dec(&buf->priority);
 	mutex_unlock(&buf->lock);
 	if (restart)
-		queue_kthread_work(&port->worker, &buf->work);
+		queue_work(system_unbound_wq, &buf->work);
 }
 EXPORT_SYMBOL_GPL(tty_buffer_unlock_exclusive);
 
@@ -133,8 +133,6 @@ void tty_buffer_free_all(struct tty_port *port)
 	buf->tail = &buf->sentinel;
 
 	atomic_set(&buf->mem_used, 0);
-	if (!IS_ERR_OR_NULL(port->worker_thread))
-		kthread_stop(port->worker_thread);
 }
 
 /**
@@ -371,11 +369,8 @@ void tty_schedule_flip(struct tty_port *port)
 {
 	struct tty_bufhead *buf = &port->buf;
 
-	/* paired w/ acquire in flush_to_ldisc(); ensures
-	 * flush_to_ldisc() sees buffer data.
-	 */
-	smp_store_release(&buf->tail->commit, buf->tail->used);
-	queue_kthread_work(&port->worker, &buf->work);
+	buf->tail->commit = buf->tail->used;
+	schedule_work(&buf->work);
 }
 EXPORT_SYMBOL(tty_schedule_flip);
 
@@ -444,7 +439,7 @@ receive_buf(struct tty_struct *tty, struct tty_buffer *head, int count)
  *		 'consumer'
  */
 
-static void flush_to_ldisc(struct kthread_work *work)
+static void flush_to_ldisc(struct work_struct *work)
 {
 	struct tty_port *port = container_of(work, struct tty_port, buf.work);
 	struct tty_bufhead *buf = &port->buf;
@@ -508,7 +503,7 @@ static void flush_to_ldisc(struct kthread_work *work)
  */
 void tty_flush_to_ldisc(struct tty_struct *tty)
 {
-	flush_kthread_work(&tty->port->buf.work);
+	flush_work(&tty->port->buf.work);
 }
 
 /**
@@ -547,18 +542,8 @@ void tty_buffer_init(struct tty_port *port)
 	init_llist_head(&buf->free);
 	atomic_set(&buf->mem_used, 0);
 	atomic_set(&buf->priority, 0);
+	INIT_WORK(&buf->work, flush_to_ldisc);
 	buf->mem_limit = TTYB_DEFAULT_MEM_LIMIT;
-	init_kthread_work(&buf->work, flush_to_ldisc);
-	init_kthread_worker(&port->worker);
-	port->worker_thread = kthread_run(kthread_worker_fn, &port->worker,
-					  "tty_worker_thread");
-	if (IS_ERR(port->worker_thread)) {
-		/*
-		 * Not good, we can't unwind, this tty is going to be really
-		 * sad...
-		 */
-		pr_err("Unable to start tty_worker_thread\n");
-	}
 }
 
 /**
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 08a587b6564..7b308d2b83a 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1635,7 +1635,7 @@ static void release_tty(struct tty_struct *tty, int idx)
 	tty->port->itty = NULL;
 	if (tty->link)
 		tty->link->port->itty = NULL;
-	flush_kthread_work(&tty->port->buf.work);
+	cancel_work_sync(&tty->port->buf.work);
 
 	if (tty->link)
 		tty_kref_put(tty->link);
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 222534b9cf1..6a34d7d0d45 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -599,10 +599,9 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
 
 	/* Restart the work queue in case no characters kick it off. Safe if
 	   already running */
-	queue_kthread_work(&tty->port->worker, &tty->port->buf.work);
+	schedule_work(&tty->port->buf.work);
 	if (o_tty)
-		queue_kthread_work(&o_tty->port->worker,
-				   &o_tty->port->buf.work);
+		schedule_work(&o_tty->port->buf.work);
 
 	tty_unlock(tty);
 	return retval;
diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index d8778d4aa34..1b9335796da 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -16,7 +16,6 @@
 #include <linux/bitops.h>
 #include <linux/delay.h>
 #include <linux/module.h>
-#include <uapi/linux/sched.h>
 
 void tty_port_init(struct tty_port *port)
 {
@@ -132,7 +131,7 @@ EXPORT_SYMBOL(tty_port_free_xmit_buf);
  */
 void tty_port_destroy(struct tty_port *port)
 {
-	flush_kthread_work(&port->buf.work);
+	cancel_work_sync(&port->buf.work);
 	tty_buffer_free_all(port);
 }
 EXPORT_SYMBOL(tty_port_destroy);
@@ -621,12 +620,3 @@ int tty_port_open(struct tty_port *port, struct tty_struct *tty,
 }
 
 EXPORT_SYMBOL(tty_port_open);
-
-int tty_port_set_policy(struct tty_port *port, int policy, int sched_priority)
-{
-	struct sched_param param = { .sched_priority = sched_priority };
-
-	return sched_setscheduler(port->worker_thread, policy, &param);
-}
-EXPORT_SYMBOL_GPL(tty_port_set_policy);
-
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 9a50ffac2b2..47d0bfa536e 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -12,7 +12,6 @@
 #include <uapi/linux/tty.h>
 #include <linux/rwsem.h>
 #include <linux/llist.h>
-#include <linux/kthread.h>
 
 
 
@@ -60,7 +59,7 @@ static inline char *flag_buf_ptr(struct tty_buffer *b, int ofs)
 
 struct tty_bufhead {
 	struct tty_buffer *head;	/* Queue head */
-	struct kthread_work work;
+	struct work_struct work;
 	struct mutex	   lock;
 	atomic_t	   priority;
 	struct tty_buffer sentinel;
@@ -219,8 +218,6 @@ struct tty_port {
 						   based drain is needed else
 						   set to size of fifo */
 	struct kref		kref;		/* Ref counter */
-	struct kthread_worker   worker;         /* worker thread */
-	struct task_struct      *worker_thread; /* worker thread */
 };
 
 /*
@@ -560,8 +557,6 @@ static inline int tty_port_users(struct tty_port *port)
 {
 	return port->count + port->blocked_open;
 }
-extern int tty_port_set_policy(struct tty_port *port, int policy,
-			       int sched_priority);
 
 extern int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc);
 extern int tty_unregister_ldisc(int disc);
-- 
2.23.0