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Commit ddde3c18 authored by Daniel Vetter's avatar Daniel Vetter
Browse files

vt: More locking checks 



I honestly have no idea what the subtle differences between
con_is_visible, con_is_fg (internal to vt.c) and con_is_bound are. But
it looks like both vc->vc_display_fg and con_driver_map are protected
by the console_lock, so probably better if we hold that when checking
this.

To do that I had to deinline the con_is_visible function.

Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Reviewed-by: default avatarSam Ravnborg <sam@ravnborg.org>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Martin Hostettler <textshell@uchuujin.de>
Cc: Adam Borowski <kilobyte@angband.pl>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190528090304.9388-5-daniel.vetter@ffwll.ch
parent a135513c

drivers/tty/vt/vt.c

+16 −0
Original line number Diff line number Diff line
@@ -3822,6 +3822,8 @@ int con_is_bound(const struct consw *csw) 
{

	int i, bound = 0;



	WARN_CONSOLE_UNLOCKED();



	for (i = 0; i < MAX_NR_CONSOLES; i++) {

		if (con_driver_map[i] == csw) {

			bound = 1;
@@ -3833,6 +3835,20 @@ int con_is_bound(const struct consw *csw) 
}

EXPORT_SYMBOL(con_is_bound);



/**

 * con_is_visible - checks whether the current console is visible

 * @vc: virtual console

 *

 * RETURNS: zero if not visible, nonzero if visible

 */

bool con_is_visible(const struct vc_data *vc)

{

	WARN_CONSOLE_UNLOCKED();



	return *vc->vc_display_fg == vc;

}

EXPORT_SYMBOL(con_is_visible);



/**

 * con_debug_enter - prepare the console for the kernel debugger

 * @sw: console driver

include/linux/console_struct.h

+1 −4
Original line number Diff line number Diff line
@@ -168,9 +168,6 @@ extern void vc_SAK(struct work_struct *work); 


#define CUR_DEFAULT CUR_UNDERLINE



static inline bool con_is_visible(const struct vc_data *vc)

{

	return *vc->vc_display_fg == vc;

}

bool con_is_visible(const struct vc_data *vc);



#endif /* _LINUX_CONSOLE_STRUCT_H */