linux-kernel - [PATCH] vt: configurable number of console devices

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Date:   Mon, 27 May 2019 21:31:17 -0700
From:   Trevor Bourget <tgb.kernel@...il.com>
To:     jslaby@...e.com, gregkh@...uxfoundation.org
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH] vt: configurable number of console devices

Having 63 vt devices for embedded systems might be overkill,
so provide a configuration MAX_NR_CONSOLES to allow this
consumption to be reduced.

Signed-off-by: Trevor Bourget <tgb.kernel@...il.com>
---
 drivers/tty/Kconfig     | 9 +++++++++
 include/uapi/linux/vt.h | 4 ++++
 2 files changed, 13 insertions(+)

diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index 3b1d312bb175..98e21589f4af 100644
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -42,6 +42,15 @@ config VT
 	  If unsure, say Y, or else you won't be able to do much with your new
 	  shiny Linux system :-)
 
+config MAX_NR_CONSOLES
+	int "Maximum number of consoles to permit"
+	depends on VT
+	range 1 63
+	default "63"
+	---help---
+	  The maximum number of consoles that can be used.
+	  The default is 63.
+
 config CONSOLE_TRANSLATIONS
 	depends on VT
 	default y
diff --git a/include/uapi/linux/vt.h b/include/uapi/linux/vt.h
index e9d39c48520a..3567dd239758 100644
--- a/include/uapi/linux/vt.h
+++ b/include/uapi/linux/vt.h
@@ -8,9 +8,13 @@
  * resizing).
  */
 #define MIN_NR_CONSOLES 1       /* must be at least 1 */
+#ifdef CONFIG_MAX_NR_CONSOLES
+#define MAX_NR_CONSOLES CONFIG_MAX_NR_CONSOLES
+#else
 #define MAX_NR_CONSOLES	63	/* serial lines start at 64 */
 		/* Note: the ioctl VT_GETSTATE does not work for
 		   consoles 16 and higher (since it returns a short) */
+#endif
 
 /* 0x56 is 'V', to avoid collision with termios and kd */
 
-- 
2.22.0.rc1.257.g3120a18244-goog