From c75300b5c64b013a6a04c8385094eeff849595ba Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Tue, 5 Apr 2022 23:03:34 +0200 Subject: [PATCH] fbcon: untangle fbcon_exit There's a bunch of confusions going on here: - The deferred fbcon setup notifier should only be cleaned up from fb_console_exit(), to be symmetric with fb_console_init() - We also need to make sure we don't race with the work, which means temporarily dropping the console lock (or we can deadlock) - That also means no point in clearing deferred_takeover, we are unloading everything anyway. - Finally rename fbcon_exit to fbcon_release_all and move it, since that's what's it doing when being called from consw->con_deinit through fbcon_deinit. To answer a question from Sam just quoting my own reply: > We loose the call to fbcon_release_all() here [in fb_console_exit()]. > We have part of the old fbcon_exit() above, but miss the release parts. Ah yes that's the entire point of this change. The release_all in the fbcon exit path was only needed when fbcon was a separate module indepedent from core fb.ko. Which means it was possible to unload fbcon while having fbdev drivers registered. But since we've merged them that has become impossible, so by the time the fb.ko module can be unloaded, there's guaranteed to be no fbdev drivers left. And hence removing them is pointless. v2: Explain the why better (Sam) Acked-by: Sam Ravnborg Signed-off-by: Daniel Vetter Cc: Daniel Vetter Cc: Greg Kroah-Hartman Cc: Claudio Suarez Cc: Du Cheng Cc: Tetsuo Handa Link: https://patchwork.freedesktop.org/patch/msgid/20220405210335.3434130-17-daniel.vetter@ffwll.ch --- drivers/video/fbdev/core/fbcon.c | 63 ++++++++++++++++++++-------------------- 1 file changed, 32 insertions(+), 31 deletions(-) diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c index 685b4a9..944f514 100644 --- a/drivers/video/fbdev/core/fbcon.c +++ b/drivers/video/fbdev/core/fbcon.c @@ -187,7 +187,6 @@ static void fbcon_redraw_move(struct vc_data *vc, struct fbcon_display *p, int line, int count, int dy); static void fbcon_modechanged(struct fb_info *info); static void fbcon_set_all_vcs(struct fb_info *info); -static void fbcon_exit(void); static struct device *fbcon_device; @@ -1146,6 +1145,27 @@ static void fbcon_free_font(struct fbcon_display *p, bool freefont) static void set_vc_hi_font(struct vc_data *vc, bool set); +static void fbcon_release_all(void) +{ + struct fb_info *info; + int i, j, mapped; + + for_each_registered_fb(i) { + mapped = 0; + info = registered_fb[i]; + + for (j = first_fb_vc; j <= last_fb_vc; j++) { + if (con2fb_map[j] == i) { + mapped = 1; + con2fb_map[j] = -1; + } + } + + if (mapped) + fbcon_release(info); + } +} + static void fbcon_deinit(struct vc_data *vc) { struct fbcon_display *p = &fb_display[vc->vc_num]; @@ -1185,7 +1205,7 @@ finished: set_vc_hi_font(vc, false); if (!con_is_bound(&fb_con)) - fbcon_exit(); + fbcon_release_all(); if (vc->vc_num == logo_shown) logo_shown = FBCON_LOGO_CANSHOW; @@ -3296,34 +3316,6 @@ static void fbcon_start(void) #endif } -static void fbcon_exit(void) -{ - struct fb_info *info; - int i, j, mapped; - -#ifdef CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER - if (deferred_takeover) { - dummycon_unregister_output_notifier(&fbcon_output_nb); - deferred_takeover = false; - } -#endif - - for_each_registered_fb(i) { - mapped = 0; - info = registered_fb[i]; - - for (j = first_fb_vc; j <= last_fb_vc; j++) { - if (con2fb_map[j] == i) { - mapped = 1; - con2fb_map[j] = -1; - } - } - - if (mapped) - fbcon_release(info); - } -} - void __init fb_console_init(void) { int i; @@ -3363,10 +3355,19 @@ static void __exit fbcon_deinit_device(void) void __exit fb_console_exit(void) { +#ifdef CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER + console_lock(); + if (deferred_takeover) + dummycon_unregister_output_notifier(&fbcon_output_nb); + console_unlock(); + + cancel_work_sync(&fbcon_deferred_takeover_work); +#endif + console_lock(); fbcon_deinit_device(); device_destroy(fb_class, MKDEV(0, 0)); - fbcon_exit(); + do_unregister_con_driver(&fb_con); console_unlock(); } -- 2.7.4