From patchwork Wed Nov 27 16:31:57 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jani Nikula X-Patchwork-Id: 11264431 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A867314DB for ; Wed, 27 Nov 2019 16:32:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 91E892073F for ; Wed, 27 Nov 2019 16:32:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726926AbfK0Qcp (ORCPT ); Wed, 27 Nov 2019 11:32:45 -0500 Received: from mga03.intel.com ([134.134.136.65]:43789 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726514AbfK0Qcp (ORCPT ); Wed, 27 Nov 2019 11:32:45 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Nov 2019 08:32:43 -0800 X-IronPort-AV: E=Sophos;i="5.69,250,1571727600"; d="scan'208";a="199239647" Received: from jnikula-mobl3.fi.intel.com (HELO localhost) ([10.237.66.161]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Nov 2019 08:32:40 -0800 From: Jani Nikula To: linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org Cc: ville.syrjala@linux.intel.com, intel-gfx@lists.freedesktop.org, jani.nikula@intel.com, Jaya Kumar Subject: [PATCH 01/13] video: fb_defio: preserve user fb_ops Date: Wed, 27 Nov 2019 18:31:57 +0200 Message-Id: <448995ffd954e0cd2287089cb686e351cc095834.1574871797.git.jani.nikula@intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: References: MIME-Version: 1.0 Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org Modifying fb_ops directly to override fb_mmap with fb_deferred_io_mmap and then resetting it to NULL afterwards causes problems all over the place. First, it prevents making the fbops member of struct fb_info a const pointer, which means we can't make struct fb_ops const anywhere. Second, a few places have to go out of their way to restore the original fb_mmap pointer that gets reset to NULL. Preserve the passed in fb_ops by making a copy of it and modifying that instead. Add a deferred_io_private member to struct fb_info to store the pointer to the old fb_ops, and restore that at cleanup. Cc: Jaya Kumar Cc: linux-fbdev@vger.kernel.org Signed-off-by: Jani Nikula --- Note: If the approach is acceptable, we'll also need to handle the error returns on memory allocation failures at fb_deferred_io_init() call sites. There are 13. --- drivers/video/fbdev/core/fb_defio.c | 25 ++++++++++++++++++++++--- include/linux/fb.h | 3 ++- 2 files changed, 24 insertions(+), 4 deletions(-) diff --git a/drivers/video/fbdev/core/fb_defio.c b/drivers/video/fbdev/core/fb_defio.c index 82c20c6047b0..36697844c1e0 100644 --- a/drivers/video/fbdev/core/fb_defio.c +++ b/drivers/video/fbdev/core/fb_defio.c @@ -200,13 +200,23 @@ static void fb_deferred_io_work(struct work_struct *work) mutex_unlock(&fbdefio->lock); } -void fb_deferred_io_init(struct fb_info *info) +int fb_deferred_io_init(struct fb_info *info) { struct fb_deferred_io *fbdefio = info->fbdefio; + struct fb_ops *fbops; BUG_ON(!fbdefio); + + fbops = kmemdup(info->fbops, sizeof(*fbops), GFP_KERNEL); + if (!fbops) + return -ENOMEM; + + fbops->fb_mmap = fb_deferred_io_mmap; + info->deferred_io_private = info->fbops; + info->fbops = fbops; + mutex_init(&fbdefio->lock); - info->fbops->fb_mmap = fb_deferred_io_mmap; + INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work); INIT_LIST_HEAD(&fbdefio->pagelist); if (fbdefio->delay == 0) /* set a default of 1 s */ @@ -229,6 +239,12 @@ void fb_deferred_io_cleanup(struct fb_info *info) int i; BUG_ON(!fbdefio); + + /* sanity check against misuse */ + if (WARN_ON(!info->deferred_io_private || + info->fbops->fb_mmap != fb_deferred_io_mmap)) + return; + cancel_delayed_work_sync(&info->deferred_work); /* clear out the mapping that we setup */ @@ -237,7 +253,10 @@ void fb_deferred_io_cleanup(struct fb_info *info) page->mapping = NULL; } - info->fbops->fb_mmap = NULL; + kfree(info->fbops); + info->fbops = info->deferred_io_private; + info->deferred_io_private = NULL; + mutex_destroy(&fbdefio->lock); } EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup); diff --git a/include/linux/fb.h b/include/linux/fb.h index a6ad528990de..65f2abd47745 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -470,6 +470,7 @@ struct fb_info { #ifdef CONFIG_FB_DEFERRED_IO struct delayed_work deferred_work; struct fb_deferred_io *fbdefio; + void *deferred_io_private; #endif struct fb_ops *fbops; @@ -658,7 +659,7 @@ static inline void __fb_pad_aligned_buffer(u8 *dst, u32 d_pitch, /* drivers/video/fb_defio.c */ int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma); -extern void fb_deferred_io_init(struct fb_info *info); +extern int fb_deferred_io_init(struct fb_info *info); extern void fb_deferred_io_open(struct fb_info *info, struct inode *inode, struct file *file);