linux-kernel - [PATCH v5 7/7] console: Introduce ->exit() callback

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Date:   Mon,  3 Feb 2020 15:31:30 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Petr Mladek <pmladek@...e.com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        linux-kernel@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: [PATCH v5 7/7] console: Introduce ->exit() callback

Some consoles might require special operations on unregistering.
For instance, serial console, when registered in the kernel,
keeps power on for entire time, until it gets unregistered.
Example of use:

	->setup(console):
		pm_runtime_get(...);

	->exit(console):
		pm_runtime_put(...);

For such cases to have a balance we would provide ->exit() callback.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
v5: Return error code from ->exit() (Sergey)

 include/linux/console.h | 1 +
 kernel/printk/printk.c  | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/include/linux/console.h b/include/linux/console.h
index f33016b3a401..7a140f4e5d0c 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -148,6 +148,7 @@ struct console {
 	struct tty_driver *(*device)(struct console *, int *);
 	void	(*unblank)(void);
 	int	(*setup)(struct console *, char *);
+	int	(*exit)(struct console *);
 	int	(*match)(struct console *, char *name, int idx, char *options);
 	short	flags;
 	short	index;
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index abd9b92ae0e3..43b5cb88c607 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2860,6 +2860,9 @@ int unregister_console(struct console *console)
 	console_unlock();
 	console_sysfs_notify();
 
+	if (console->exit)
+		res = console->exit(console);
+
 	return res;
 
 out_disable_unlock:
-- 
2.24.1