From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 361CCC433F5 for ; Tue, 8 Feb 2022 13:56:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229829AbiBHN4k (ORCPT ); Tue, 8 Feb 2022 08:56:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47608 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376864AbiBHN4j (ORCPT ); Tue, 8 Feb 2022 08:56:39 -0500 Received: from mail-wr1-x430.google.com (mail-wr1-x430.google.com [IPv6:2a00:1450:4864:20::430]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 25060C03FED2 for ; Tue, 8 Feb 2022 05:56:38 -0800 (PST) Received: by mail-wr1-x430.google.com with SMTP id i14so1257360wrc.10 for ; Tue, 08 Feb 2022 05:56:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:cc:subject:message-id:mail-followup-to:references :mime-version:content-disposition:in-reply-to; bh=O/7417wNQCN4SuMaNTwcVKN+ZflwWgOUCIPC+jiRE/o=; b=Ew0LBKyyZZg7bw9TJmpVuYAYXcHmtjfUHDVj7FrAp9ZH8ajDNFW8U6BnR/JiOt4nzW PaCd3vXMwp7M/Dm9bNm/zpuvmivc2iaAFZUv6ZwzFyKlXURnG3XGpJliMBFsWShgVw5j ENO1C8RYNForJhZG+YhFWvcq4hbfLgfhHAbRQ= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id :mail-followup-to:references:mime-version:content-disposition :in-reply-to; bh=O/7417wNQCN4SuMaNTwcVKN+ZflwWgOUCIPC+jiRE/o=; b=KR4aYG4A3PDKPApRYtehKvofU6CED7aq/axyG0yvz/dSAnrjcUBdh61kU9spWKso6n OT8bEQmRx6v7ZBp4l22dUzkfc0M16WI1V2vFqdl0n+2a9xmq4vBHbsqnQZXzakFsxcDn wT/4Jpj9TGQou37vzHf/IERZFIcEC4J1DsK9ZrV+9DCFzn/t1IDMY/VHdVCstluEC6fR wDGLydFIuGGoqPAsGFOKWI1KAltkD+umMmRUHXzeze6unYGfGz3gCy31Uz/P1h6DWWzb H4GeuLFGQ+oGo5ei/3dGQL6axVmsbewIHmbICnEf1xfeLgw6i2WPzYLTk9RYJIvIAcYb uncA== X-Gm-Message-State: AOAM530PvSrl/kSGPao0OjF6H8xivG+eScI5ITAhV5OH6tHpwVkttcSR DG4R49p20Aw6+2M+ciVO/7qha829zSwC1w== X-Google-Smtp-Source: ABdhPJywjPxKkAwnXbVLdTzSYAhDUTqfE7kVbx67xjjQpyqk07POVfshuilESB0J8Up36dslkKnnyA== X-Received: by 2002:a5d:4a06:: with SMTP id m6mr3751562wrq.37.1644328596738; Tue, 08 Feb 2022 05:56:36 -0800 (PST) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id b11sm776039wmq.26.2022.02.08.05.56.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Feb 2022 05:56:35 -0800 (PST) Date: Tue, 8 Feb 2022 14:56:33 +0100 From: Daniel Vetter To: Sam Ravnborg Cc: Daniel Vetter , DRI Development , linux-fbdev@vger.kernel.org, Thomas Zimmermann , Xiyu Yang , Du Cheng , Tetsuo Handa , Intel Graphics Development , Zheyu Ma , LKML , Matthew Wilcox , Claudio Suarez , Greg Kroah-Hartman , Alex Deucher , Daniel Vetter , Zhen Lei , Guenter Roeck Subject: Re: [PATCH 16/21] fbcon: Move console_lock for register/unlink/unregister Message-ID: Mail-Followup-To: Sam Ravnborg , DRI Development , linux-fbdev@vger.kernel.org, Thomas Zimmermann , Xiyu Yang , Du Cheng , Tetsuo Handa , Intel Graphics Development , Zheyu Ma , LKML , Matthew Wilcox , Claudio Suarez , Greg Kroah-Hartman , Alex Deucher , Daniel Vetter , Zhen Lei , Guenter Roeck References: <20220131210552.482606-1-daniel.vetter@ffwll.ch> <20220131210552.482606-17-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: Linux phenom 5.10.0-8-amd64 Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org On Fri, Feb 04, 2022 at 08:54:24PM +0100, Sam Ravnborg wrote: > Hi Daniel. > > On Mon, Jan 31, 2022 at 10:05:47PM +0100, Daniel Vetter wrote: > > 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(). > > > > Signed-off-by: Daniel Vetter > > Cc: Daniel Vetter > > Cc: Thomas Zimmermann > > Cc: Du Cheng > > Cc: Claudio Suarez > > Cc: Greg Kroah-Hartman > > Cc: Tetsuo Handa > > Cc: Matthew Wilcox > > Cc: Sam Ravnborg > > Cc: Zheyu Ma > > Cc: Guenter Roeck > > Cc: Alex Deucher > > Cc: Zhen Lei > > Cc: Xiyu Yang > > Like how lock_console is now almost local to fbcon. > Except the usage outside fbmem + fbcon taht is. Yeah that's the goal. The problem is that moving console_lock for the remaining fb_pan and fb_set_var calls will mean we need to put lock_fbinfo() calls into fbcon.c, and right now that's just not impossible. The FIXME update at the end of the series tries to explain this a bit more. -Daniel > > Acked-by: Sam Ravnborg > > > --- > > drivers/video/fbdev/core/fbcon.c | 33 ++++++++++++++++++++++++++------ > > drivers/video/fbdev/core/fbmem.c | 23 ++-------------------- > > 2 files changed, 29 insertions(+), 27 deletions(-) > > > > diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c > > index 11b9f962af6f..e5e8aaf6f60d 100644 > > --- a/drivers/video/fbdev/core/fbcon.c > > +++ b/drivers/video/fbdev/core/fbcon.c > > @@ -2776,10 +2776,12 @@ 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 && > > @@ -2814,6 +2816,8 @@ void fbcon_fb_unbind(struct fb_info *info) > > } > > fbcon_unbind(); > > } > > + > > + console_unlock(); > > } > > > > /* called with console_lock held */ > > @@ -2821,10 +2825,12 @@ 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++) { > > @@ -2853,6 +2859,7 @@ 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) > > @@ -2910,19 +2917,27 @@ 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) { > > @@ -2942,6 +2957,12 @@ int fbcon_fb_registered(struct fb_info *info) > > } > > } > > > > +out: > > + if (!lockless_register_fb) > > + console_unlock(); > > + else > > + atomic_dec(&ignore_console_lock_warning); > > + > > return ret; > > } > > > > diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c > > index fd51d12f2702..904ef1250677 100644 > > --- a/drivers/video/fbdev/core/fbmem.c > > +++ b/drivers/video/fbdev/core/fbmem.c > > @@ -1573,14 +1573,9 @@ 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)) > > @@ -1649,17 +1644,7 @@ 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) > > @@ -1669,9 +1654,7 @@ 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) > > @@ -1714,9 +1697,7 @@ 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); > > -- > > 2.33.0 -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch