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 X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30695C5CFEB for ; Wed, 11 Jul 2018 15:07:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D1A662087C for ; Wed, 11 Jul 2018 15:07:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="Bo4Shqdl" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D1A662087C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388684AbeGKPMK (ORCPT ); Wed, 11 Jul 2018 11:12:10 -0400 Received: from mail-io0-f195.google.com ([209.85.223.195]:44982 "EHLO mail-io0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733215AbeGKPMK (ORCPT ); Wed, 11 Jul 2018 11:12:10 -0400 Received: by mail-io0-f195.google.com with SMTP id q19-v6so23894483ioh.11 for ; Wed, 11 Jul 2018 08:07:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=BzRzKELxpdBJz9/E7dj4w5AVy+a7rjIm2RvxD9VU5I0=; b=Bo4ShqdlPiBc+AGaDjPPRDNlMnXW3HHpIvkUzacIN+PpWEtgFSL6zq6rtZYj8y0d2R RhtvOz+k/f1ZIGv0UIpOhcz9HokQYvAimmZWIC70V0dc7qrXxjgRwDtt1I3AK25mxhvI w8tVe4Z/HLCDKpOpsRoR74pZXOPKWWHepq13c= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=BzRzKELxpdBJz9/E7dj4w5AVy+a7rjIm2RvxD9VU5I0=; b=G2S8ZrVdfCO5x1FB1hOzgj16VjrCVBZel0UujfeQUPSZYmunKdXvwmHQXkfyeBNs0z CdV6XJy3sy8mWsKFBOEHqAwB3OOkBZdFH5a0FMzNbG80qL+FNTG8iTd3rVGzhFi4VOSK G2y+KsKaSJ8Z/ksx/gCPm05MSIdVxl8rfMYcfE/7gCO2UA180gNaBcqAssbHBkFVCQVq ipU7j3a9kHxh4W76XiMfIS7xI1qB98kzApjSUikDVbOavqKB0XM+k2jjazBkVvKSxA5M S6CI43mIRSAuqmeaWB2uRaGMhzsGpfHWy20sMi7dR8cymCU3xCNTH33TzxTQYwtT80rF kDoA== X-Gm-Message-State: AOUpUlE1AyTapTq0Jjfzf0GbFCTxKReYx6TnvI6qzUQ6CUUizbv0oKvJ D5nm01W1Vllz2oZCal6v2sDFjiicdeYPu1kWKdkqfQ== X-Google-Smtp-Source: AAOMgpfzXCIa69CEgIJ1XaHn4enM6hUUY5Jirwtn4nFmVLOcVjc1rb3uibkuw6mqtp/L2O6WFEwyREXHigZUEbzkLOQ= X-Received: by 2002:a6b:f418:: with SMTP id i24-v6mr25735066iog.34.1531321643940; Wed, 11 Jul 2018 08:07:23 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a4f:e492:0:0:0:0:0 with HTTP; Wed, 11 Jul 2018 08:07:23 -0700 (PDT) X-Originating-IP: [212.51.149.109] In-Reply-To: <386d987c-899a-2e98-66ba-6e672dd532ef@redhat.com> References: <20180628090351.15581-1-hdegoede@redhat.com> <20180628090351.15581-3-hdegoede@redhat.com> <717e6337-e7a6-7a92-1c1b-8929a25696b5@suse.de> <20180711105255.32803a3c@gandalf.local.home> <386d987c-899a-2e98-66ba-6e672dd532ef@redhat.com> From: Daniel Vetter Date: Wed, 11 Jul 2018 17:07:23 +0200 X-Google-Sender-Auth: YaBf6XpPKO-h6CQ7Y_erEwCf570 Message-ID: Subject: Re: [PATCH v5 2/3] fbcon: Call WARN_CONSOLE_UNLOCKED() where applicable To: Hans de Goede Cc: Steven Rostedt , Thomas Zimmermann , Petr Mladek , Linux Fbdev development list , Bartlomiej Zolnierkiewicz , Linux Kernel Mailing List , dri-devel , Sergey Senozhatsky Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 11, 2018 at 5:01 PM, Hans de Goede wrote: > Hi, > > On 11-07-18 16:52, Steven Rostedt wrote: >> >> On Wed, 11 Jul 2018 16:46:11 +0200 >> Thomas Zimmermann wrote: >> >>> Hi >>> >>> Am 28.06.2018 um 11:03 schrieb Hans de Goede: >>>> >>>> Replace comments about places where the console lock should be held with >>>> calls to WARN_CONSOLE_UNLOCKED() to assert that it is actually held. >>> >>> >>> Debugging fbcon sometimes requires to not take the console lock. This >>> patch breaks the debugging workaround provided by >>> 'fb.lockless_register_fb'. The dmesg is now filled with warnings about >>> the missing lock. >>> >> >> What if you make lockless_register_fb visible to fbcon, and then we can >> have a macro: >> >> #define WARN_FB_CONSOLE_UNLOCKED() \ >> do { \ >> if (unlikely(!lockless_register_fb)) \ >> WARN_CONSOLE_UNLOCKED(); \ >> } while (0) >> >> And use that instead? > > > Yes I'm already preparing a patch like that :) > > Without the unlikely though, this is not used in hot paths. Note that you don't even need an EXPORT_SYMBOL since this is all in the same module. -Daniel > Regards, > > Hans > > > > >> >> -- Steve >> >> >>> Best regards >>> Thomas >>> >>>> Acked-by: Steven Rostedt (VMware) >>>> Reviewed-by: Daniel Vetter >>>> Reviewed-by: Sergey Senozhatsky >>>> Signed-off-by: Hans de Goede >>>> --- >>>> Changes in v3: >>>> -New patch in v3 of this patchset >>>> >>>> Changes in v4: >>>> -Keep the comments about which fbcon functions need locks in place >>>> --- >>>> drivers/video/fbdev/core/fbcon.c | 11 +++++++++++ >>>> 1 file changed, 11 insertions(+) >>>> >>>> diff --git a/drivers/video/fbdev/core/fbcon.c >>>> b/drivers/video/fbdev/core/fbcon.c >>>> index c910e74d46ff..cd8d52a967aa 100644 >>>> --- a/drivers/video/fbdev/core/fbcon.c >>>> +++ b/drivers/video/fbdev/core/fbcon.c >>>> @@ -828,6 +828,8 @@ static int set_con2fb_map(int unit, int newidx, int >>>> user) >>>> struct fb_info *oldinfo = NULL; >>>> int found, err = 0; >>>> + WARN_CONSOLE_UNLOCKED(); >>>> + >>>> if (oldidx == newidx) >>>> return 0; >>>> @@ -3044,6 +3046,8 @@ static int fbcon_fb_unbind(int idx) >>>> { >>>> int i, new_idx = -1, ret = 0; >>>> + WARN_CONSOLE_UNLOCKED(); >>>> + >>>> if (!fbcon_has_console_bind) >>>> return 0; >>>> @@ -3094,6 +3098,8 @@ static int fbcon_fb_unregistered(struct fb_info >>>> *info) >>>> { >>>> int i, idx; >>>> + WARN_CONSOLE_UNLOCKED(); >>>> + >>>> idx = info->node; >>>> for (i = first_fb_vc; i <= last_fb_vc; i++) { >>>> if (con2fb_map[i] == idx) >>>> @@ -3131,6 +3137,9 @@ static int fbcon_fb_unregistered(struct fb_info >>>> *info) >>>> static void fbcon_remap_all(int idx) >>>> { >>>> int i; >>>> + >>>> + WARN_CONSOLE_UNLOCKED(); >>>> + >>>> for (i = first_fb_vc; i <= last_fb_vc; i++) >>>> set_con2fb_map(i, idx, 0); >>>> @@ -3177,6 +3186,8 @@ static int fbcon_fb_registered(struct fb_info >>>> *info) >>>> { >>>> int ret = 0, i, idx; >>>> + WARN_CONSOLE_UNLOCKED(); >>>> + >>>> idx = info->node; >>>> fbcon_select_primary(info); >>>> >>> >>> >> > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch