vt: selection, introduce vc_is_sel

BugLink: https://bugs.launchpad.net/bugs/1873852

commit dce05aa6 upstream.

Avoid global variables (namely sel_cons) by introducing vc_is_sel. It
checks whether the parameter is the current selection console. This will
help putting sel_cons to a struct later.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-1-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

drivers/tty/vt/selection.c

@@ -80,6 +80,11 @@ void clear_selection(void)
 	}
 }
 
+bool vc_is_sel(struct vc_data *vc)
+{
+	return vc == sel_cons;
+}
+
 /*
  * User settable table: what characters are to be considered alphabetic?
  * 256 bits. Locked by the console lock.

drivers/tty/vt/vt.c

@@ -604,8 +604,9 @@ static void hide_softcursor(struct vc_data *vc)
 
 static void hide_cursor(struct vc_data *vc)
 {
-	if (vc == sel_cons)
+	if (vc_is_sel(vc))
 		clear_selection();
+
 	vc->vc_sw->con_cursor(vc, CM_ERASE);
 	hide_softcursor(vc);
 }
@@ -616,7 +617,7 @@ static void set_cursor(struct vc_data *vc)
 	    vc->vc_mode == KD_GRAPHICS)
 		return;
 	if (vc->vc_deccm) {
-		if (vc == sel_cons)
+		if (vc_is_sel(vc))
 			clear_selection();
 		add_softcursor(vc);
 		if ((vc->vc_cursor_type & 0x0f) != 1)
@@ -889,7 +890,7 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
 	if (!newscreen)
 		return -ENOMEM;
 
-	if (vc == sel_cons)
+	if (vc_is_sel(vc))
 		clear_selection();
 
 	old_rows = vc->vc_rows;

drivers/tty/vt/vt_ioctl.c

@@ -42,7 +42,7 @@ char vt_dont_switch;
 extern struct tty_driver *console_driver;
 
 #define VT_IS_IN_USE(i)	(console_driver->ttys[i] && console_driver->ttys[i]->count)
-#define VT_BUSY(i)	(VT_IS_IN_USE(i) || i == fg_console || vc_cons[i].d == sel_cons)
+#define VT_BUSY(i)	(VT_IS_IN_USE(i) || i == fg_console || vc_is_sel(vc_cons[i].d))
 
 /*
  * Console (vt and kd) routines, as defined by USL SVR4 manual, and by

include/linux/selection.h

@@ -12,8 +12,8 @@
 
 struct tty_struct;
 
-extern struct vc_data *sel_cons;
 struct tty_struct;
+struct vc_data;
 
 extern void clear_selection(void);
 extern int set_selection(const struct tiocl_selection __user *sel, struct tty_struct *tty);
@@ -22,6 +22,8 @@ extern int sel_loadlut(char __user *p);
 extern int mouse_reporting(void);
 extern void mouse_report(struct tty_struct * tty, int butt, int mrx, int mry);
 
+bool vc_is_sel(struct vc_data *vc);
+
 extern int console_blanked;
 
 extern unsigned char color_table[];