[PATCH 4.9 156/191] ALSA: usb-audio: Clean up mixer element list traverse

Sasha Levin
2020-06-29T20:22:36Z

From: Takashi Iwai <tiwai@suse.de>

[ Upstream commit 8c558076c740e8009a96c6fdc3d4245dde62be77 ]

Introduce a new macro for iterating over mixer element list for
avoiding the open codes in many places. Also the open-coded
container_of() and the forced cast to struct usb_mixer_elem_info are
replaced with another simple macro, too.

No functional changes but just readability improvement.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
sound/usb/mixer.c | 20 +++++++++-----------
sound/usb/mixer.h | 6 ++++++
sound/usb/mixer_quirks.c | 2 +-
sound/usb/mixer_scarlett.c | 6 ++----
4 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 60423d2572c7d..97ce7b7269847 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -2397,9 +2397,9 @@ void snd_usb_mixer_notify_id(struct usb_mixer_interface *mixer, int unitid)
{
struct usb_mixer_elem_list *list;

- for (list = mixer->id_elems[unitid]; list; list = list->next_id_elem) {
+ for_each_mixer_elem(list, mixer, unitid) {
struct usb_mixer_elem_info *info =
- (struct usb_mixer_elem_info *)list;
+ mixer_elem_list_to_info(list);
/* invalidate cache, so the value is read from the device */
info->cached = 0;
snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
@@ -2410,7 +2410,7 @@ void snd_usb_mixer_notify_id(struct usb_mixer_interface *mixer, int unitid)
static void snd_usb_mixer_dump_cval(struct snd_info_buffer *buffer,
struct usb_mixer_elem_list *list)
{
- struct usb_mixer_elem_info *cval = (struct usb_mixer_elem_info *)list;
+ struct usb_mixer_elem_info *cval = mixer_elem_list_to_info(list);
static char *val_types[] = {"BOOLEAN", "INV_BOOLEAN",
"S8", "U8", "S16", "U16"};
snd_iprintf(buffer, " Info: id=%i, control=%i, cmask=0x%x, "
@@ -2436,8 +2436,7 @@ static void snd_usb_mixer_proc_read(struct snd_info_entry *entry,
mixer->ignore_ctl_error);
snd_iprintf(buffer, "Card: %s\n", chip->card->longname);
for (unitid = 0; unitid < MAX_ID_ELEMS; unitid++) {
- for (list = mixer->id_elems[unitid]; list;
- list = list->next_id_elem) {
+ for_each_mixer_elem(list, mixer, unitid) {
snd_iprintf(buffer, " Unit: %i\n", list->id);
if (list->kctl)
snd_iprintf(buffer,
@@ -2467,19 +2466,19 @@ static void snd_usb_mixer_interrupt_v2(struct usb_mixer_interface *mixer,
return;
}

- for (list = mixer->id_elems[unitid]; list; list = list->next_id_elem)
+ for_each_mixer_elem(list, mixer, unitid)
count++;

if (count == 0)
return;

- for (list = mixer->id_elems[unitid]; list; list = list->next_id_elem) {
+ for_each_mixer_elem(list, mixer, unitid) {
struct usb_mixer_elem_info *info;

if (!list->kctl)
continue;

- info = (struct usb_mixer_elem_info *)list;
+ info = mixer_elem_list_to_info(list);
if (count > 1 && info->control != control)
continue;

@@ -2699,7 +2698,7 @@ int snd_usb_mixer_suspend(struct usb_mixer_interface *mixer)

static int restore_mixer_value(struct usb_mixer_elem_list *list)
{
- struct usb_mixer_elem_info *cval = (struct usb_mixer_elem_info *)list;
+ struct usb_mixer_elem_info *cval = mixer_elem_list_to_info(list);
int c, err, idx;

if (cval->cmask) {
@@ -2735,8 +2734,7 @@ int snd_usb_mixer_resume(struct usb_mixer_interface *mixer, bool reset_resume)
if (reset_resume) {
/* restore cached mixer values */
for (id = 0; id < MAX_ID_ELEMS; id++) {
- for (list = mixer->id_elems[id]; list;
- list = list->next_id_elem) {
+ for_each_mixer_elem(list, mixer, id) {
if (list->resume) {
err = list->resume(list);
if (err < 0)
diff --git a/sound/usb/mixer.h b/sound/usb/mixer.h
index 545d99b09706b..004d99037210f 100644
--- a/sound/usb/mixer.h
+++ b/sound/usb/mixer.h
@@ -52,6 +52,12 @@ struct usb_mixer_elem_list {
usb_mixer_elem_resume_func_t resume;
};

+/* iterate over mixer element list of the given unit id */
+#define for_each_mixer_elem(list, mixer, id) \
+ for ((list) = (mixer)->id_elems[id]; (list); (list) = (list)->next_id_elem)
+#define mixer_elem_list_to_info(list) \
+ container_of(list, struct usb_mixer_elem_info, head)
+
struct usb_mixer_elem_info {
struct usb_mixer_elem_list head;
unsigned int control; /* CS or ICN (high byte) */
diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
index 723b535ca2ec5..5d6af9c861ad9 100644
--- a/sound/usb/mixer_quirks.c
+++ b/sound/usb/mixer_quirks.c
@@ -1170,7 +1170,7 @@ void snd_emuusb_set_samplerate(struct snd_usb_audio *chip,
int unitid = 12; /* SamleRate ExtensionUnit ID */

list_for_each_entry(mixer, &chip->mixer_list, list) {
- cval = (struct usb_mixer_elem_info *)mixer->id_elems[unitid];
+ cval = mixer_elem_list_to_info(mixer->id_elems[unitid]);
if (cval) {
snd_usb_mixer_set_ctl_value(cval, UAC_SET_CUR,
cval->control << 8,
diff --git a/sound/usb/mixer_scarlett.c b/sound/usb/mixer_scarlett.c
index 7438e7c4a842d..2876cd9b35b38 100644
--- a/sound/usb/mixer_scarlett.c
+++ b/sound/usb/mixer_scarlett.c
@@ -287,8 +287,7 @@ static int scarlett_ctl_switch_put(struct snd_kcontrol *kctl,

static int scarlett_ctl_resume(struct usb_mixer_elem_list *list)
{
- struct usb_mixer_elem_info *elem =
- container_of(list, struct usb_mixer_elem_info, head);
+ struct usb_mixer_elem_info *elem = mixer_elem_list_to_info(list);
int i;

for (i = 0; i < elem->channels; i++)
@@ -447,8 +446,7 @@ static int scarlett_ctl_enum_put(struct snd_kcontrol *kctl,

static int scarlett_ctl_enum_resume(struct usb_mixer_elem_list *list)
{
- struct usb_mixer_elem_info *elem =
- container_of(list, struct usb_mixer_elem_info, head);
+ struct usb_mixer_elem_info *elem = mixer_elem_list_to_info(list);

if (elem->cached)
snd_usb_set_cur_mix_value(elem, 0, 0, *elem->cache_val);
--
2.25.1