From patchwork Sun Mar 27 00:25:01 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tasos Sahanidis X-Patchwork-Id: 12792700 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E19C0C433F5 for ; Sun, 27 Mar 2022 00:25:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231356AbiC0A0n (ORCPT ); Sat, 26 Mar 2022 20:26:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55722 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231355AbiC0A0m (ORCPT ); Sat, 26 Mar 2022 20:26:42 -0400 Received: from devnull.tasossah.com (devnull.tasossah.com [IPv6:2001:41d0:1:e60e::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4531A6558 for ; Sat, 26 Mar 2022 17:25:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=devnull.tasossah.com; s=vps; h=Content-Transfer-Encoding:Content-Type: Subject:From:Cc:To:MIME-Version:Date:Message-ID:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=J5Tr4CW4pAWnQXKhgmegpJDahYFOkyyMsLhx8253VDw=; b=PHLyMGjd61unvKoE05ryk97jdT k08iGQ/G5tGblZZXK5mU/EDC8I94BX2ZIvWymT9X8OkitFrwxSFZYJ+5VT1K0qbbdi4YpLuCDTagw LmjzGl2JawoYpP13mPIlEaMREkAHkHJYCKwz/yBW/M4rt2eniI5ROw1Vw456ebpRQ0q4=; Received: from [2a02:587:6a16:2a00::298] by devnull.tasossah.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1nYGiL-009RnZ-TK; Sun, 27 Mar 2022 02:25:02 +0200 Message-ID: <2450973f-d665-82b9-6734-4b57f95a2be3@tasossah.com> Date: Sun, 27 Mar 2022 02:25:01 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Content-Language: en-US To: linux-usb@vger.kernel.org Cc: gregkh@linuxfoundation.org, stern@rowland.harvard.edu, tasos@tasossah.com From: Tasos Sahanidis Subject: [PATCH v2] usb: core: Don't block while sleeping in do_proc_control() Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Since commit ae8709b296d8 ("USB: core: Make do_proc_control() and do_proc_bulk() killable") if a device has the USB_QUIRK_DELAY_CTRL_MSG quirk set, it will temporarily block all other URBs (e.g. interrupts) while sleeping due to a control. This results in noticeable delays when, for example, a userspace usbfs application is sending URB interrupts at a high rate to a keyboard and simultaneously updates the lock indicators using controls. Interrupts with direction set to IN are also affected by this, meaning that delivery of HID reports (containing scancodes) to the usbfs application is delayed as well. This patch fixes the regression by calling msleep() while the device mutex is unlocked, as was the case originally with usb_control_msg(). Fixes: ae8709b296d8 ("USB: core: Make do_proc_control() and do_proc_bulk() killable") Signed-off-by: Tasos Sahanidis Acked-by: Alan Stern --- drivers/usb/core/devio.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index 6abb7294e919..b5b85bf80329 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -1209,12 +1209,16 @@ static int do_proc_control(struct usb_dev_state *ps, usb_unlock_device(dev); i = usbfs_start_wait_urb(urb, tmo, &actlen); + + /* Linger a bit, prior to the next control message. */ + if (dev->quirks & USB_QUIRK_DELAY_CTRL_MSG) + msleep(200); usb_lock_device(dev); snoop_urb(dev, NULL, pipe, actlen, i, COMPLETE, tbuf, actlen); if (!i && actlen) { if (copy_to_user(ctrl->data, tbuf, actlen)) { ret = -EFAULT; - goto recv_fault; + goto done; } } } else { @@ -1231,6 +1235,10 @@ static int do_proc_control(struct usb_dev_state *ps, usb_unlock_device(dev); i = usbfs_start_wait_urb(urb, tmo, &actlen); + + /* Linger a bit, prior to the next control message. */ + if (dev->quirks & USB_QUIRK_DELAY_CTRL_MSG) + msleep(200); usb_lock_device(dev); snoop_urb(dev, NULL, pipe, actlen, i, COMPLETE, NULL, 0); } @@ -1242,10 +1250,6 @@ static int do_proc_control(struct usb_dev_state *ps, } ret = (i < 0 ? i : actlen); - recv_fault: - /* Linger a bit, prior to the next control message. */ - if (dev->quirks & USB_QUIRK_DELAY_CTRL_MSG) - msleep(200); done: kfree(dr); usb_free_urb(urb);