From patchwork Tue Jan 19 00:09:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Davidlohr Bueso X-Patchwork-Id: 12028447 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 40841C433DB for ; Tue, 19 Jan 2021 00:10:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0B7E322EBF for ; Tue, 19 Jan 2021 00:10:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390897AbhASAKY (ORCPT ); Mon, 18 Jan 2021 19:10:24 -0500 Received: from mx2.suse.de ([195.135.220.15]:47356 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731557AbhASAKX (ORCPT ); Mon, 18 Jan 2021 19:10:23 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 12CF9AAAE; Tue, 19 Jan 2021 00:09:41 +0000 (UTC) From: Davidlohr Bueso To: gregkh@linuxfoundation.org Cc: mathias.nyman@intel.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, dave@stgolabs.net, Davidlohr Bueso Subject: [PATCH] usb: xhci: Replace tasklet with work Date: Mon, 18 Jan 2021 16:09:30 -0800 Message-Id: <20210119000930.127469-1-dave@stgolabs.net> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Tasklets have long been deprecated as being too heavy on the system by running in irq context - and this is not a performance critical path. If a higher priority process wants to run, it must wait for the tasklet to finish before doing so. dbc_rx_push() will now run in process context and have further concurrency - tasklets being serialized among themselves, but this is done holding the port_lock, so it should be fine. Signed-off-by: Davidlohr Bueso --- drivers/usb/host/xhci-dbgcap.h | 2 +- drivers/usb/host/xhci-dbgtty.c | 19 +++++++++++-------- 2 files changed, 12 insertions(+), 9 deletions(-) diff --git a/drivers/usb/host/xhci-dbgcap.h b/drivers/usb/host/xhci-dbgcap.h index c70b78d504eb..aec66009af51 100644 --- a/drivers/usb/host/xhci-dbgcap.h +++ b/drivers/usb/host/xhci-dbgcap.h @@ -104,7 +104,7 @@ struct dbc_port { struct list_head read_pool; struct list_head read_queue; unsigned int n_read; - struct tasklet_struct push; + struct work_struct push; struct list_head write_pool; struct kfifo write_fifo; diff --git a/drivers/usb/host/xhci-dbgtty.c b/drivers/usb/host/xhci-dbgtty.c index ae4e4ab638b5..50da77d92cf6 100644 --- a/drivers/usb/host/xhci-dbgtty.c +++ b/drivers/usb/host/xhci-dbgtty.c @@ -108,7 +108,7 @@ dbc_read_complete(struct xhci_dbc *dbc, struct dbc_request *req) spin_lock_irqsave(&port->port_lock, flags); list_add_tail(&req->list_pool, &port->read_queue); - tasklet_schedule(&port->push); + schedule_work(&port->push); spin_unlock_irqrestore(&port->port_lock, flags); } @@ -272,7 +272,7 @@ static void dbc_tty_unthrottle(struct tty_struct *tty) unsigned long flags; spin_lock_irqsave(&port->port_lock, flags); - tasklet_schedule(&port->push); + schedule_work(&port->push); spin_unlock_irqrestore(&port->port_lock, flags); } @@ -288,15 +288,18 @@ static const struct tty_operations dbc_tty_ops = { .unthrottle = dbc_tty_unthrottle, }; -static void dbc_rx_push(struct tasklet_struct *t) +static void dbc_rx_push(struct work_struct *work) { struct dbc_request *req; struct tty_struct *tty; unsigned long flags; bool do_push = false; bool disconnect = false; - struct dbc_port *port = from_tasklet(port, t, push); - struct list_head *queue = &port->read_queue; + struct dbc_port *port; + struct list_head *queue; + + port = container_of(work, struct dbc_port, push); + queue = &port->read_queue; spin_lock_irqsave(&port->port_lock, flags); tty = port->port.tty; @@ -349,7 +352,7 @@ static void dbc_rx_push(struct tasklet_struct *t) if (!list_empty(queue) && tty) { if (!tty_throttled(tty)) { if (do_push) - tasklet_schedule(&port->push); + schedule_work(&port->push); else pr_warn("ttyDBC0: RX not scheduled?\n"); } @@ -382,7 +385,7 @@ xhci_dbc_tty_init_port(struct xhci_dbc *dbc, struct dbc_port *port) { tty_port_init(&port->port); spin_lock_init(&port->port_lock); - tasklet_setup(&port->push, dbc_rx_push); + INIT_WORK(&port->push, dbc_rx_push); INIT_LIST_HEAD(&port->read_pool); INIT_LIST_HEAD(&port->read_queue); INIT_LIST_HEAD(&port->write_pool); @@ -394,7 +397,7 @@ xhci_dbc_tty_init_port(struct xhci_dbc *dbc, struct dbc_port *port) static void xhci_dbc_tty_exit_port(struct dbc_port *port) { - tasklet_kill(&port->push); + cancel_work_sync(&port->push); tty_port_destroy(&port->port); }