Commit 6e7da3af authored by Daniel Vetter's avatar Daniel Vetter
Browse files

fbcon: Move console_lock for register/unlink/unregister 



Ideally console_lock becomes an implementation detail of fbcon.c and
doesn't show up anywhere in fbmem.c. We're still pretty far from that,
but at least the register/unregister code is there now.

With this the do_fb_ioctl() handler is the only code in fbmem.c still
calling console_lock().

Acked-by: default avatarSam Ravnborg <sam@ravnborg.org>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Du Cheng <ducheng2@gmail.com>
Cc: Claudio Suarez <cssk@net-c.es>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Zheyu Ma <zheyuma97@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405210335.3434130-15-daniel.vetter@ffwll.ch
parent 43553559

drivers/video/fbdev/core/fbcon.c

+27 −6
Original line number Diff line number Diff line
@@ -2756,10 +2756,12 @@ void fbcon_fb_unbind(struct fb_info *info) 
	int i, new_idx = -1;

	int idx = info->node;



	WARN_CONSOLE_UNLOCKED();

	console_lock();



	if (!fbcon_has_console_bind)

	if (!fbcon_has_console_bind) {

		console_unlock();

		return;

	}



	for (i = first_fb_vc; i <= last_fb_vc; i++) {

		if (con2fb_map[i] != idx &&
@@ -2794,6 +2796,8 @@ void fbcon_fb_unbind(struct fb_info *info) 
		}

		fbcon_unbind();

	}



	console_unlock();

}



/* called with console_lock held */
@@ -2801,10 +2805,12 @@ void fbcon_fb_unregistered(struct fb_info *info) 
{

	int i, idx;



	WARN_CONSOLE_UNLOCKED();

	console_lock();



	if (deferred_takeover)

	if (deferred_takeover) {

		console_unlock();

		return;

	}



	idx = info->node;

	for (i = first_fb_vc; i <= last_fb_vc; i++) {
@@ -2833,6 +2839,7 @@ void fbcon_fb_unregistered(struct fb_info *info) 


	if (!num_registered_fb)

		do_unregister_con_driver(&fb_con);

	console_unlock();

}



void fbcon_remap_all(struct fb_info *info)
@@ -2890,19 +2897,27 @@ static inline void fbcon_select_primary(struct fb_info *info) 
}

#endif /* CONFIG_FRAMEBUFFER_DETECT_PRIMARY */



static bool lockless_register_fb;

module_param_named_unsafe(lockless_register_fb, lockless_register_fb, bool, 0400);

MODULE_PARM_DESC(lockless_register_fb,

	"Lockless framebuffer registration for debugging [default=off]");



/* called with console_lock held */

int fbcon_fb_registered(struct fb_info *info)

{

	int ret = 0, i, idx;



	WARN_CONSOLE_UNLOCKED();

	if (!lockless_register_fb)

		console_lock();

	else

		atomic_inc(&ignore_console_lock_warning);



	idx = info->node;

	fbcon_select_primary(info);



	if (deferred_takeover) {

		pr_info("fbcon: Deferring console take-over\n");

		return 0;

		goto out;

	}



	if (info_idx == -1) {
@@ -2922,6 +2937,12 @@ int fbcon_fb_registered(struct fb_info *info) 
		}

	}



out:

	if (!lockless_register_fb)

		console_unlock();

	else

		atomic_dec(&ignore_console_lock_warning);



	return ret;

}

drivers/video/fbdev/core/fbmem.c

+2 −21
Original line number Diff line number Diff line
@@ -1590,14 +1590,9 @@ static void do_remove_conflicting_framebuffers(struct apertures_struct *a, 
	}

}



static bool lockless_register_fb;

module_param_named_unsafe(lockless_register_fb, lockless_register_fb, bool, 0400);

MODULE_PARM_DESC(lockless_register_fb,

	"Lockless framebuffer registration for debugging [default=off]");



static int do_register_framebuffer(struct fb_info *fb_info)

{

	int i, ret;

	int i;

	struct fb_videomode mode;



	if (fb_check_foreignness(fb_info))
@@ -1666,17 +1661,7 @@ static int do_register_framebuffer(struct fb_info *fb_info) 
	}

#endif



	if (!lockless_register_fb)

		console_lock();

	else

		atomic_inc(&ignore_console_lock_warning);

	ret = fbcon_fb_registered(fb_info);



	if (!lockless_register_fb)

		console_unlock();

	else

		atomic_dec(&ignore_console_lock_warning);

	return ret;

	return fbcon_fb_registered(fb_info);

}



static void unbind_console(struct fb_info *fb_info)
@@ -1686,9 +1671,7 @@ static void unbind_console(struct fb_info *fb_info) 
	if (WARN_ON(i < 0 || i >= FB_MAX || registered_fb[i] != fb_info))

		return;



	console_lock();

	fbcon_fb_unbind(fb_info);

	console_unlock();

}



static void unlink_framebuffer(struct fb_info *fb_info)
@@ -1731,9 +1714,7 @@ static void do_unregister_framebuffer(struct fb_info *fb_info) 
		fb_notifier_call_chain(FB_EVENT_FB_UNREGISTERED, &event);

	}

#endif

	console_lock();

	fbcon_fb_unregistered(fb_info);

	console_unlock();



	/* this may free fb info */

	put_fb_info(fb_info);