From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Deucher Subject: Re: [PATCH 03/12] drm: call ->firstopen() before ->open() Date: Thu, 24 Jul 2014 09:47:21 -0400 Message-ID: References: <1406129207-1302-1-git-send-email-dh.herrmann@gmail.com> <1406129207-1302-4-git-send-email-dh.herrmann@gmail.com> <20140723192529.GZ15237@phenom.ffwll.local> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-qa0-f51.google.com (mail-qa0-f51.google.com [209.85.216.51]) by gabe.freedesktop.org (Postfix) with ESMTP id 842246E700 for ; Thu, 24 Jul 2014 06:47:22 -0700 (PDT) Received: by mail-qa0-f51.google.com with SMTP id k15so2937893qaq.10 for ; Thu, 24 Jul 2014 06:47:22 -0700 (PDT) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: David Herrmann Cc: Daniel Vetter , "dri-devel@lists.freedesktop.org" List-Id: dri-devel@lists.freedesktop.org On Thu, Jul 24, 2014 at 5:31 AM, David Herrmann wrote: > Hi > > On Wed, Jul 23, 2014 at 9:25 PM, Daniel Vetter wrote: >> On Wed, Jul 23, 2014 at 05:26:38PM +0200, David Herrmann wrote: >>> Lets order things correctly: >>> ->load() >>> ->fistopen() >>> ->open() >>> ->close() >>> ->lastclose() >>> ->unload() >>> >>> This doesn't change much as only savage and radeon use ->firstopen() and >>> they just do map-initialization. Therefore, the global drm mutex makes >>> sure there cannot be any other f_op between ->open() and ->firstopen(). >>> However, once we get rid of that lock, we really want ->firstopen() to >>> initialize the device before ->open() is called. >>> >>> Furthermore, this fixes the clean-up path in drm_open(). We currently >>> don't cleanup the drm_file object if ->firstopen() fails. >>> >>> Signed-off-by: David Herrmann >>> --- >>> drivers/gpu/drm/drm_fops.c | 139 +++++++++++++++++++++------------------------ >>> include/drm/drmP.h | 2 +- >>> 2 files changed, 66 insertions(+), 75 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c >>> index 021fe5d..8e73519 100644 >>> --- a/drivers/gpu/drm/drm_fops.c >>> +++ b/drivers/gpu/drm/drm_fops.c >>> @@ -45,7 +45,7 @@ EXPORT_SYMBOL(drm_global_mutex); >>> >>> static int drm_open_helper(struct file *filp, struct drm_minor *minor); >>> >>> -static int drm_setup(struct drm_device * dev) >>> +static int drm_firstopen(struct drm_device * dev) >> >> All the stuff in here is only for legacy drivers. Imo we should rename >> this to drm_legacy_setup and hide it harder. >> >> Also touching the init ordering for ums drivers is a bit risky, I'd advise >> against it. firstopen is officially dead for kms driver and really there's >> nothing legit you can do in there. imx abused until they've switched over >> to the component framework. >> >> I'd just drop this one tbh. > > I did a driver audit when writing this patch, there're only 2 drivers > using firstopen: > > * radeon_cp: sets two fields of dev_private and calls drm_addmap() on > those. In lastclose(), it calls drm_rmmap() > * savage: sets several fields in dev_private, calls > arch_phys_wc_add() for some regions and requests a drm-map for those > via drm_addmap(). On lastclose(), it reverts exactly those steps. > > Taking into account that firstopen() just runs with drm_device > context, not with drm_file context, I really think we should be > calling it _before_ doing ->open(). I even think the drivers would > fail horribly if we don't do this patch and some other user-context > sneaks in between both calls (currently impossible thanks to > drm_global_mutex). > > Both ->firstopen() callbacks are fairly trivial. In favor of making > the error-paths work in drm_open() I'd really like to get this in. > This patch is preparing for my drm_file rework that can make > drm_dev_unregister() stop all open files immediately. > > But I honestly don't care much for UMS drivers, so if you NACK this, > I'd just ignore the error code and add a comment that we don't do > error-handling for UMS. Well, radeon UMS support is in the kernel deprecated and hasn't been built by default for a while and I doubt anyone has tested it in years. I'm not sure what the current state of savage is. I'm fine either way. Alex > > Cheers > David > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel