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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5043BC3DA7D for ; Tue, 3 Jan 2023 06:11:06 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8151210E038; Tue, 3 Jan 2023 06:11:05 +0000 (UTC) Received: from msg-4.mailo.com (msg-4.mailo.com [213.182.54.15]) by gabe.freedesktop.org (Postfix) with ESMTPS id B19B010E038; Tue, 3 Jan 2023 06:11:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=mailo.com; s=mailo; t=1672726250; bh=0QiT1nP/zMPKUUDkAaMQ9yUdD8F2H0QNgooG7N7zyYo=; h=X-EA-Auth:Date:From:To:Cc:Subject:Message-ID:References: MIME-Version:Content-Type:In-Reply-To; b=CGYs3/tiizCf+/L3lXkL0NWpc0RhDBAuqvsTgaTwyzT14WUXuzEuZoRfol0zCB+Qw 4exrqcEUM+8ZxNgVz0czUIghW6dOHz87DaS152oVZ5z4bfBDeUqkwegyJxivA7oefq CkWPg3CsS5yg+wqNqkjkLzZy4K9FKL3R7bh9gI8c= Received: by b-4.in.mailobj.net [192.168.90.14] with ESMTP via ip-206.mailobj.net [213.182.55.206] Tue, 3 Jan 2023 07:10:50 +0100 (CET) X-EA-Auth: CzIsRrexWLW7eUEvE38Rmurn8QV0CbPV93zNoPpkz0v0X1ipkUmOKjGxx7AZJk/AO0tNh0AGIiqB5iQKzPzEPAcyxOzDhIDX Date: Tue, 3 Jan 2023 11:40:44 +0530 From: Deepak R Varma To: Rodrigo Vivi , Nicolai Stange , Julia Lawall Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Intel-gfx] [PATCH] drm/i915/fbc: Avoid full proxy f_ops for FBC debug attributes X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Saurabh Singh Sengar , Praveen Kumar , intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, Deepak R Varma , dri-devel@lists.freedesktop.org, Daniel Vetter , David Airlie Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Wed, Dec 28, 2022 at 06:18:12AM -0500, Rodrigo Vivi wrote: > On Tue, Dec 27, 2022 at 11:36:13PM +0530, Deepak R Varma wrote: > > On Tue, Dec 27, 2022 at 12:13:56PM -0500, Rodrigo Vivi wrote: > > > On Tue, Dec 27, 2022 at 01:30:53PM +0530, Deepak R Varma wrote: > > > > Using DEFINE_SIMPLE_ATTRIBUTE macro with the debugfs_create_file() > > > > function adds the overhead of introducing a proxy file operation > > > > functions to wrap the original read/write inside file removal protection > > > > functions. This adds significant overhead in terms of introducing and > > > > managing the proxy factory file operations structure and function > > > > wrapping at runtime. > > > > As a replacement, a combination of DEFINE_DEBUGFS_ATTRIBUTE macro paired > > > > with debugfs_create_file_unsafe() is suggested to be used instead. The > > > > DEFINE_DEBUGFS_ATTRIBUTE utilises debugfs_file_get() and > > > > debugfs_file_put() wrappers to protect the original read and write > > > > function calls for the debug attributes. There is no need for any > > > > runtime proxy file operations to be managed by the debugfs core. > > > > > > > > This Change is reported by the debugfs_simple_attr.cocci Coccinelle > > > > semantic patch. > > > > > > I just checked here with > > > $ make coccicheck M=drivers/gpu/drm/i915/ MODE=context COCCI=./scripts/coccinelle/api/debugfs/debugfs_simple_attr.cocci > > > > Hello Rodrigo, > > Thank you so much for your review and feedback on the patch proposal. > > > > > > > > The part reported by the this script is the s/SIMPLE/DEBUGFS > > > but the change to the unsafe option is not. > > > > If you look at the original commit of this coccinelle file, it calls out the > > need for pairing debugfs_create_file_unsafe() as well. Please review this > > > > commitID: 5103068eaca2: ("debugfs, coccinelle: check for obsolete DEFINE_SIMPLE_ATTRIBUTE() usage") > > +Nicolai and Julia. > > It looks like coccinelle got right the > - DEFINE_SIMPLE_ATTRIBUTE(dsa_fops, dsa_get, dsa_set, dsa_fmt); > + DEFINE_DEBUGFS_ATTRIBUTE(dsa_fops, dsa_get, dsa_set, dsa_fmt); > > but it failed badly on > - debugfs_create_file(name, mode, parent, data, &dsa_fops) > + debugfs_create_file_unsafe(name, mode, parent, data, &dsa_fops) > > > > > Based on my review of the code, the functions debugfs_create_file() and > > debugfs_create_file_unsafe(), both internally call __debugfs_create_file(). > > However, they pass debugfs_full_proxy_file_operations and > > debugfs_open_proxy_file_operations respectively to it. The former represents the > > full proxy factory, where as the later one is lightweight open proxy > > implementation of the file operations structure. > > > > > > > > This commit message is not explaining why the unsafe is the suggested > > > or who suggested it. > > > > If you find the response above accurate, I will include these details about > > the _unsafe() function in my commit message in v2. > > > > > > > > If you remove the unsafe part feel free to resend adding: > > > > Please confirm you still believe switching to _unsafe() is not necessary. > > Based on the coccinelle commit it looks like you are right, but cocinelle > just failed to detect the case. Let's see what Nicolai and Julia respond > before we move with any patch here. Hello Nicolai and Julia, Can you please review this proposed patch and the feedback comments from Rodrigo please? Thank you, ./drv > > > > > > > > > Reviewed-by: Rodrigo Vivi > > > (to both patches, this and the drrs one. > > > > > > Also, it looks like you could contribute with other 2 patches: > > > drivers/gpu/drm/i915/pxp/intel_pxp_debugfs.c:64:0-23: WARNING: pxp_terminate_fops should be defined with DEFINE_DEBUGFS_ATTRIBUTE > > > drivers/gpu/drm/i915/gvt/debugfs.c:150:0-23: WARNING: vgpu_scan_nonprivbb_fops should be defined with DEFINE_DEBUGFS_ATTRIBUTE > > > > Yes, these are on my list. Was waiting for a feedback on the first submission > > before I send more similar patches. > > > > Appreciate your time and the feedback. > > > > > > Regards, > > ./drv > > > > > > > > > > > > > Signed-off-by: Deepak R Varma > > > > --- > > > > drivers/gpu/drm/i915/display/intel_fbc.c | 12 ++++++------ > > > > 1 file changed, 6 insertions(+), 6 deletions(-) > > > > > > > > diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c > > > > index b5ee5ea0d010..4b481e2f908b 100644 > > > > --- a/drivers/gpu/drm/i915/display/intel_fbc.c > > > > +++ b/drivers/gpu/drm/i915/display/intel_fbc.c > > > > @@ -1809,10 +1809,10 @@ static int intel_fbc_debugfs_false_color_set(void *data, u64 val) > > > > return 0; > > > > } > > > > > > > > -DEFINE_SIMPLE_ATTRIBUTE(intel_fbc_debugfs_false_color_fops, > > > > - intel_fbc_debugfs_false_color_get, > > > > - intel_fbc_debugfs_false_color_set, > > > > - "%llu\n"); > > > > +DEFINE_DEBUGFS_ATTRIBUTE(intel_fbc_debugfs_false_color_fops, > > > > + intel_fbc_debugfs_false_color_get, > > > > + intel_fbc_debugfs_false_color_set, > > > > + "%llu\n"); > > > > > > > > static void intel_fbc_debugfs_add(struct intel_fbc *fbc, > > > > struct dentry *parent) > > > > @@ -1821,8 +1821,8 @@ static void intel_fbc_debugfs_add(struct intel_fbc *fbc, > > > > fbc, &intel_fbc_debugfs_status_fops); > > > > > > > > if (fbc->funcs->set_false_color) > > > > - debugfs_create_file("i915_fbc_false_color", 0644, parent, > > > > - fbc, &intel_fbc_debugfs_false_color_fops); > > > > + debugfs_create_file_unsafe("i915_fbc_false_color", 0644, parent, > > > > + fbc, &intel_fbc_debugfs_false_color_fops); > > > > } > > > > > > > > void intel_fbc_crtc_debugfs_add(struct intel_crtc *crtc) > > > > -- > > > > 2.34.1 > > > > > > > > > > > > > > > > >