Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753908AbdCTJya (ORCPT ); Mon, 20 Mar 2017 05:54:30 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:35312 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753019AbdCTJyZ (ORCPT ); Mon, 20 Mar 2017 05:54:25 -0400 Date: Mon, 20 Mar 2017 10:54:15 +0100 From: Daniel Vetter To: Arnd Bergmann Cc: Daniel Vetter , Jani Nikula , David Airlie , Tvrtko Ursulin , intel-gfx@lists.freedesktop.org, Joonas Lahtinen , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Matthew Auld Subject: Re: [PATCH 1/3] drm/i915: allocate mock file pointer dynamically Message-ID: <20170320095415.a5spxvbpknjnmvm7@phenom.ffwll.local> Mail-Followup-To: Arnd Bergmann , Daniel Vetter , Jani Nikula , David Airlie , Tvrtko Ursulin , intel-gfx@lists.freedesktop.org, Joonas Lahtinen , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Matthew Auld References: <20170320094335.1266306-1-arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170320094335.1266306-1-arnd@arndb.de> X-Operating-System: Linux phenom 4.8.0-1-amd64 User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2724 Lines: 72 On Mon, Mar 20, 2017 at 10:40:27AM +0100, Arnd Bergmann wrote: > A struct file is a bit too large to put on the kernel stack in general > and triggers a warning for low settings of CONFIG_FRAME_WARN: > > drivers/gpu/drm/i915/selftests/mock_drm.c: In function 'mock_file': > drivers/gpu/drm/i915/selftests/mock_drm.c:46:1: error: the frame size of 1328 bytes is larger than 1280 bytes [-Werror=frame-larger-than=] > drivers/gpu/drm/i915/selftests/mock_drm.c: In function 'mock_file_free': > drivers/gpu/drm/i915/selftests/mock_drm.c:54:1: error: the frame size of 1312 bytes is larger than 1280 bytes [-Werror=frame-larger-than=] > > It's also slightly dangerous to leave a reference to a stack object > in the drm_file structure after leaving the stack frame. > This changes the code to just allocate the object dynamically > and release it when we are done with it. > > Fixes: 66d9cb5d805a ("drm/i915: Mock the GEM device for self-testing") > Signed-off-by: Arnd Bergmann > --- > drivers/gpu/drm/i915/selftests/mock_drm.c | 12 +++++++----- > 1 file changed, 7 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/i915/selftests/mock_drm.c b/drivers/gpu/drm/i915/selftests/mock_drm.c > index 113dec05c7dc..18514065c93d 100644 > --- a/drivers/gpu/drm/i915/selftests/mock_drm.c > +++ b/drivers/gpu/drm/i915/selftests/mock_drm.c > @@ -32,15 +32,15 @@ static inline struct inode fake_inode(struct drm_i915_private *i915) > struct drm_file *mock_file(struct drm_i915_private *i915) > { > struct inode inode = fake_inode(i915); > - struct file filp = {}; > + struct file *filp = kzalloc(sizeof(struct file), GFP_KERNEL); > struct drm_file *file; > int err; > > - err = drm_open(&inode, &filp); > + err = drm_open(&inode, filp); Aside: We should have a FIXME and/or merge David Herrmanns code to allow a drm_file without a real struct file for kernel-internal use ... -Daniel > if (unlikely(err)) > return ERR_PTR(err); > > - file = filp.private_data; > + file = filp->private_data; > file->authenticated = true; > return file; > } > @@ -48,7 +48,9 @@ struct drm_file *mock_file(struct drm_i915_private *i915) > void mock_file_free(struct drm_i915_private *i915, struct drm_file *file) > { > struct inode inode = fake_inode(i915); > - struct file filp = { .private_data = file }; > + struct file *filp = file->filp; > > - drm_release(&inode, &filp); > + drm_release(&inode, filp); > + > + kfree(filp); > } > -- > 2.9.0 > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch