From patchwork Tue Feb 26 11:19:46 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikulas Patocka X-Patchwork-Id: 10829925 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2DC7F1575 for ; Tue, 26 Feb 2019 11:29:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1A2BF2A6B3 for ; Tue, 26 Feb 2019 11:29:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0DBD52A7BF; Tue, 26 Feb 2019 11:29:57 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 94FE02A6B3 for ; Tue, 26 Feb 2019 11:29:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725935AbfBZL34 (ORCPT ); Tue, 26 Feb 2019 06:29:56 -0500 Received: from smtp01.tmcz.cz ([93.153.104.112]:39968 "EHLO smtp01.tmcz.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726283AbfBZL34 (ORCPT ); Tue, 26 Feb 2019 06:29:56 -0500 Received: from smtp01.tmcz.cz (localhost [127.0.0.1]) by sagator.hkvnode045 (Postfix) with ESMTP id C9335949FBC; Tue, 26 Feb 2019 12:21:32 +0100 (CET) X-Sagator-Scanner: 1.3.1-1 at hkvnode045; log(status(custom_action(quarantine(clamd()))), status(custom_action(quarantine(SpamAssassinD())))) X-Sagator-ID: 20190226-122132-0001-02459-EbplNO@hkvnode045 Received: from leontynka.twibright.com (unknown [109.183.129.149]) by smtp01.tmcz.cz (Postfix) with ESMTPS; Tue, 26 Feb 2019 12:21:32 +0100 (CET) Received: from root by leontynka.twibright.com with local (Exim 4.89) (envelope-from ) id 1gyana-0002q5-Cc; Tue, 26 Feb 2019 12:21:22 +0100 Message-Id: <20190226112122.160829572@twibright.com> User-Agent: quilt/0.63-1 Date: Tue, 26 Feb 2019 12:19:46 +0100 From: Mikulas Patocka To: Mikulas Patocka , Bernie Thompson , Bartlomiej Zolnierkiewicz , Ladislav Michl Cc: linux-fbdev@vger.kernel.org Subject: [PATCH 2/3] udlfb: fix sleeping inside spinlock References: <20190226111944.505404435@twibright.com> MIME-Version: 1.0 Content-Disposition: inline; filename=dlfb-offload-damage.patch Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If a framebuffer device is used as a console, the rendering calls (copyarea, fillrect, imageblit) may be done with the console spinlock held. On udlfb, these function call dlfb_handle_damage that takes a blocking semaphore before acquiring an URB. In order to fix the bug, this patch changes the calls copyarea, fillrect and imageblit to offload USB work to a workqueue. A side effect of this patch is 3x improvement in console scrolling speed because the device doesn't have to be updated after each copyarea call. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org --- drivers/video/fbdev/udlfb.c | 56 +++++++++++++++++++++++++++++++++++++++++--- include/video/udlfb.h | 6 ++++ 2 files changed, 59 insertions(+), 3 deletions(-) Index: linux-4.19.25/drivers/video/fbdev/udlfb.c =================================================================== --- linux-4.19.25.orig/drivers/video/fbdev/udlfb.c 2019-02-25 16:19:19.000000000 +0100 +++ linux-4.19.25/drivers/video/fbdev/udlfb.c 2019-02-25 16:23:05.000000000 +0100 @@ -657,6 +657,50 @@ error: return 0; } +static void dlfb_init_damage(struct dlfb_data *dlfb) +{ + dlfb->damage_x = INT_MAX; + dlfb->damage_x2 = 0; + dlfb->damage_y = INT_MAX; + dlfb->damage_y2 = 0; +} + +static void dlfb_damage_work(struct work_struct *w) +{ + struct dlfb_data *dlfb = container_of(w, struct dlfb_data, damage_work); + int x, x2, y, y2; + + spin_lock_irq(&dlfb->damage_lock); + x = dlfb->damage_x; + x2 = dlfb->damage_x2; + y = dlfb->damage_y; + y2 = dlfb->damage_y2; + dlfb_init_damage(dlfb); + spin_unlock_irq(&dlfb->damage_lock); + + if (x < x2 && y < y2) + dlfb_handle_damage(dlfb, x, y, x2 - x, y2 - y); +} + +static void dlfb_offload_damage(struct dlfb_data *dlfb, int x, int y, int width, int height) +{ + unsigned long flags; + int x2 = x + width; + int y2 = y + height; + + if (x >= x2 || y >= y2) + return; + + spin_lock_irqsave(&dlfb->damage_lock, flags); + dlfb->damage_x = min(x, dlfb->damage_x); + dlfb->damage_x2 = max(x2, dlfb->damage_x2); + dlfb->damage_y = min(y, dlfb->damage_y); + dlfb->damage_y2 = max(y2, dlfb->damage_y2); + spin_unlock_irqrestore(&dlfb->damage_lock, flags); + + schedule_work(&dlfb->damage_work); +} + /* * Path triggered by usermode clients who write to filesystem * e.g. cat filename > /dev/fb1 @@ -693,7 +737,7 @@ static void dlfb_ops_copyarea(struct fb_ sys_copyarea(info, area); - dlfb_handle_damage(dlfb, area->dx, area->dy, + dlfb_offload_damage(dlfb, area->dx, area->dy, area->width, area->height); } @@ -704,7 +748,7 @@ static void dlfb_ops_imageblit(struct fb sys_imageblit(info, image); - dlfb_handle_damage(dlfb, image->dx, image->dy, + dlfb_offload_damage(dlfb, image->dx, image->dy, image->width, image->height); } @@ -715,7 +759,7 @@ static void dlfb_ops_fillrect(struct fb_ sys_fillrect(info, rect); - dlfb_handle_damage(dlfb, rect->dx, rect->dy, rect->width, + dlfb_offload_damage(dlfb, rect->dx, rect->dy, rect->width, rect->height); } @@ -940,6 +984,8 @@ static void dlfb_ops_destroy(struct fb_i { struct dlfb_data *dlfb = info->par; + cancel_work_sync(&dlfb->damage_work); + if (info->cmap.len != 0) fb_dealloc_cmap(&info->cmap); if (info->monspecs.modedb) @@ -1636,6 +1682,10 @@ static int dlfb_usb_probe(struct usb_int dlfb->ops = dlfb_ops; info->fbops = &dlfb->ops; + dlfb_init_damage(dlfb); + spin_lock_init(&dlfb->damage_lock); + INIT_WORK(&dlfb->damage_work, dlfb_damage_work); + INIT_LIST_HEAD(&info->modelist); if (!dlfb_alloc_urb_list(dlfb, WRITES_IN_FLIGHT, MAX_TRANSFER)) { Index: linux-4.19.25/include/video/udlfb.h =================================================================== --- linux-4.19.25.orig/include/video/udlfb.h 2019-02-25 16:19:19.000000000 +0100 +++ linux-4.19.25/include/video/udlfb.h 2019-02-25 16:19:19.000000000 +0100 @@ -48,6 +48,12 @@ struct dlfb_data { int base8; u32 pseudo_palette[256]; int blank_mode; /*one of FB_BLANK_ */ + int damage_x; + int damage_y; + int damage_x2; + int damage_y2; + spinlock_t damage_lock; + struct work_struct damage_work; struct fb_ops ops; /* blit-only rendering path metrics, exposed through sysfs */ atomic_t bytes_rendered; /* raw pixel-bytes driver asked to render */