From mboxrd@z Thu Jan 1 00:00:00 1970 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 C998CC00A8F for ; Tue, 24 Oct 2023 12:34:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233752AbjJXMeD (ORCPT ); Tue, 24 Oct 2023 08:34:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58482 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231876AbjJXMeC (ORCPT ); Tue, 24 Oct 2023 08:34:02 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 18A6190 for ; Tue, 24 Oct 2023 05:33:59 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 6C55A21BC6; 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Tue, 24 Oct 2023 12:33:58 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 1D1dB7a5N2U+aQAAMHmgww (envelope-from ); Tue, 24 Oct 2023 12:33:58 +0000 Date: Tue, 24 Oct 2023 14:33:57 +0200 Message-ID: <87ttqgurm2.wl-tiwai@suse.de> From: Takashi Iwai To: Matias Ezequiel Vara Larsen Cc: anton.yakovlev@opensynergy.com, mst@redhat.com, perex@perex.cz, tiwai@suse.com, virtualization@lists.linux-foundation.org, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com, stefanha@redhat.com, sgarzare@redhat.com, manos.pitsidianakis@linaro.org, mripard@redhat.com Subject: Re: [PATCH v3] ALSA: virtio: use ack callback In-Reply-To: References: <87edhlwd7b.wl-tiwai@suse.de> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/27.2 Mule/6.0 MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII Authentication-Results: smtp-out1.suse.de; none X-Spamd-Result: default: False [-10.10 / 50.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; NEURAL_HAM_LONG(-3.00)[-1.000]; MIME_GOOD(-0.10)[text/plain]; REPLY(-4.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-1.00)[-1.000]; RCPT_COUNT_TWELVE(0.00)[13]; MID_CONTAINS_FROM(1.00)[]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[]; BAYES_HAM(-3.00)[99.98%] Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 24 Oct 2023 13:12:35 +0200, Matias Ezequiel Vara Larsen wrote: > > On Mon, Oct 23, 2023 at 05:50:00PM +0200, Takashi Iwai wrote: > > On Mon, 23 Oct 2023 17:06:57 +0200, > > Matias Ezequiel Vara Larsen wrote: > > > > > > +static int virtsnd_pcm_ack(struct snd_pcm_substream *substream) > > > +{ > > > + struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream); > > > + struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss); > > > + unsigned long flags; > > > + struct snd_pcm_runtime *runtime = vss->substream->runtime; > > > + ssize_t appl_pos = frames_to_bytes(runtime, runtime->control->appl_ptr); > > > + ssize_t buf_size = frames_to_bytes(runtime, runtime->buffer_size); > > > + int rc; > > > + > > > + spin_lock_irqsave(&queue->lock, flags); > > > + spin_lock(&vss->lock); > > > + > > > + ssize_t bytes = (appl_pos - vss->appl_ptr) % buf_size; > > > > The variable declaration should be moved to the beginning of the > > function. > > > > Also, there can be a overlap beyond runtime->boundary (which easily > > happens for 32bit apps), so the calculation can be a bit more complex > > with conditional. > > > > Should I use as an example `cs46xx_playback/capture_transfer()` which relies on > the `snd_pcm_indirect_playback/capture_transfer()`? It looks like it > does already that calculation. Yes, using the existing helper is a good idea. The only problem is that this helper isn't well documented ;-< thanks, Takashi