From patchwork Mon Jan 11 04:28:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Davidlohr Bueso X-Patchwork-Id: 360802 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, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 117ADC433E0 for ; Mon, 11 Jan 2021 04:30:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D5CCA22527 for ; Mon, 11 Jan 2021 04:30:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726029AbhAKE3p (ORCPT ); Sun, 10 Jan 2021 23:29:45 -0500 Received: from mx2.suse.de ([195.135.220.15]:42110 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725797AbhAKE3p (ORCPT ); Sun, 10 Jan 2021 23:29:45 -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 60140AC95; Mon, 11 Jan 2021 04:29:03 +0000 (UTC) From: Davidlohr Bueso To: balbi@kernel.org Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, dave@stgolabs.net, Takashi Iwai , Davidlohr Bueso Subject: [PATCH] usb/gadget: f_midi: Replace tasklet with work Date: Sun, 10 Jan 2021 20:28:55 -0800 Message-Id: <20210111042855.73289-1-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 Currently a tasklet is used to transmit input substream buffer data. However, 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. Deferring work to a workqueue and executing in process context should be fine considering the callback already does f_midi_do_transmit() under the transmit_lock and thus changes in semantics are ok regarding concurrency - tasklets being serialized against itself. Cc: Takashi Iwai Signed-off-by: Davidlohr Bueso Reviewed-by: Takashi Iwai --- drivers/usb/gadget/function/f_midi.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c index 8fff995b8dd5..71a1a26e85c7 100644 --- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -87,7 +87,7 @@ struct f_midi { struct snd_rawmidi_substream *out_substream[MAX_PORTS]; unsigned long out_triggered; - struct tasklet_struct tasklet; + struct work_struct work; unsigned int in_ports; unsigned int out_ports; int index; @@ -698,9 +698,11 @@ static void f_midi_transmit(struct f_midi *midi) f_midi_drop_out_substreams(midi); } -static void f_midi_in_tasklet(struct tasklet_struct *t) +static void f_midi_in_work(struct work_struct *work) { - struct f_midi *midi = from_tasklet(midi, t, tasklet); + struct f_midi *midi; + + midi = container_of(work, struct f_midi, work); f_midi_transmit(midi); } @@ -737,7 +739,7 @@ static void f_midi_in_trigger(struct snd_rawmidi_substream *substream, int up) VDBG(midi, "%s() %d\n", __func__, up); midi->in_ports_array[substream->number].active = up; if (up) - tasklet_hi_schedule(&midi->tasklet); + queue_work(system_highpri_wq, &midi->work); } static int f_midi_out_open(struct snd_rawmidi_substream *substream) @@ -875,7 +877,7 @@ static int f_midi_bind(struct usb_configuration *c, struct usb_function *f) int status, n, jack = 1, i = 0, endpoint_descriptor_index = 0; midi->gadget = cdev->gadget; - tasklet_setup(&midi->tasklet, f_midi_in_tasklet); + INIT_WORK(&midi->work, f_midi_in_work); status = f_midi_register_card(midi); if (status < 0) goto fail_register;