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Thu, 12 Mar 2026 06:34:31 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id Ap8zBHdesmnMcAAAD6G6ig (envelope-from ); Thu, 12 Mar 2026 06:34:31 +0000 Date: Thu, 12 Mar 2026 07:34:30 +0100 Message-ID: <87tsuld095.wl-tiwai@suse.de> From: Takashi Iwai To: Rosen Penev Cc: linux-sound@vger.kernel.org, Jaroslav Kysela , Takashi Iwai , linux-kernel@vger.kernel.org (open list) Subject: Re: [PATCH] ALSA: usb-audio: use kzalloc_flex In-Reply-To: <20260311232748.18697-1-rosenp@gmail.com> References: <20260311232748.18697-1-rosenp@gmail.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/30.2 Mule/6.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-Spam-Score: -3.30 X-Spam-Level: X-Spamd-Result: default: False [-3.30 / 50.00]; BAYES_HAM(-3.00)[100.00%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; FUZZY_RATELIMITED(0.00)[rspamd.com]; RCVD_VIA_SMTP_AUTH(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; TO_DN_SOME(0.00)[]; FREEMAIL_TO(0.00)[gmail.com]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_FIVE(0.00)[5]; FROM_EQ_ENVFROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,suse.de:mid] X-Spam-Flag: NO On Thu, 12 Mar 2026 00:27:48 +0100, Rosen Penev wrote: > > Saves one allocation by using a flexible array member. As it's a fixed size array, it doesn't have to be a flex array at all, so it can be even simpler. thanks, Takashi > > Signed-off-by: Rosen Penev > --- > sound/usb/mixer.c | 22 +++++++--------------- > sound/usb/mixer.h | 5 +++-- > 2 files changed, 10 insertions(+), 17 deletions(-) > > diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c > index 7007e0c9489b..337815b9e72c 100644 > --- a/sound/usb/mixer.c > +++ b/sound/usb/mixer.c > @@ -1393,7 +1393,7 @@ static int mixer_ctl_feature_info(struct snd_kcontrol *kcontrol, > if (!cval->initialized) { > get_min_max_with_quirks(cval, 0, kcontrol); > if (cval->initialized && cval->dBmin >= cval->dBmax) { > - kcontrol->vd[0].access &= > + kcontrol->vd[0].access &= > ~(SNDRV_CTL_ELEM_ACCESS_TLV_READ | > SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK); > snd_ctl_notify(cval->head.mixer->chip->card, > @@ -3006,15 +3006,12 @@ static void snd_usb_mixer_free(struct usb_mixer_interface *mixer) > snd_usb_mixer_disconnect(mixer); > > /* Unregister controls first, snd_ctl_remove() frees the element */ > - if (mixer->id_elems) { > - for (id = 0; id < MAX_ID_ELEMS; id++) { > - for (list = mixer->id_elems[id]; list; list = next) { > - next = list->next_id_elem; > - if (list->kctl) > - snd_ctl_remove(mixer->chip->card, list->kctl); > - } > + for (id = 0; id < MAX_ID_ELEMS; id++) { > + for (list = mixer->id_elems[id]; list; list = next) { > + next = list->next_id_elem; > + if (list->kctl) > + snd_ctl_remove(mixer->chip->card, list->kctl); > } > - kfree(mixer->id_elems); > } > if (mixer->urb) { > kfree(mixer->urb->transfer_buffer); > @@ -3652,16 +3649,11 @@ int snd_usb_create_mixer(struct snd_usb_audio *chip, int ctrlif) > > strscpy(chip->card->mixername, "USB Mixer"); > > - mixer = kzalloc_obj(*mixer); > + mixer = kzalloc_flex(*mixer, id_elems, MAX_ID_ELEMS); > if (!mixer) > return -ENOMEM; > mixer->chip = chip; > mixer->ignore_ctl_error = !!(chip->quirk_flags & QUIRK_FLAG_IGNORE_CTL_ERROR); > - mixer->id_elems = kzalloc_objs(*mixer->id_elems, MAX_ID_ELEMS); > - if (!mixer->id_elems) { > - kfree(mixer); > - return -ENOMEM; > - } > > mixer->hostif = &usb_ifnum_to_if(chip->dev, ctrlif)->altsetting[0]; > switch (get_iface_desc(mixer->hostif)->bInterfaceProtocol) { > diff --git a/sound/usb/mixer.h b/sound/usb/mixer.h > index 167fbfcf01ac..30dd30b925fc 100644 > --- a/sound/usb/mixer.h > +++ b/sound/usb/mixer.h > @@ -19,8 +19,6 @@ struct usb_mixer_interface { > struct list_head list; > unsigned int ignore_ctl_error; > struct urb *urb; > - /* array[MAX_ID_ELEMS], indexed by unit id */ > - struct usb_mixer_elem_list **id_elems; > > /* the usb audio specification version this interface complies to */ > int protocol; > @@ -42,6 +40,9 @@ struct usb_mixer_interface { > void *private_data; > void (*private_free)(struct usb_mixer_interface *mixer); > void (*private_suspend)(struct usb_mixer_interface *mixer); > + > + /* array[MAX_ID_ELEMS], indexed by unit id */ > + struct usb_mixer_elem_list *id_elems[]; > }; > > #define MAX_CHANNELS 16 /* max logical channels */ > -- > 2.53.0 >