ALSA: seq: Fix assignment in if condition

There are lots of places doing assignments in if condition in ALSA
sequencer core, which is a bad coding style that may confuse readers
and occasionally lead to bugs.

This patch is merely for coding-style fixes, no functional changes.

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Takashi Iwai <[e-mail]>

sound/core/seq/oss/seq_oss.c

···
 {
 	int rc;
 
-	if ((rc = register_device()) < 0)
+	rc = register_device();
+	if (rc < 0)
 		goto error;
-	if ((rc = register_proc()) < 0) {
+	rc = register_proc();
+	if (rc < 0) {
 		unregister_device();
 		goto error;
 	}
-	if ((rc = snd_seq_oss_create_client()) < 0) {
+	rc = snd_seq_oss_create_client();
+	if (rc < 0) {
 		unregister_proc();
 		unregister_device();
 		goto error;
···
 {
 	struct seq_oss_devinfo *dp;
 
-	if ((dp = file->private_data) == NULL)
+	dp = file->private_data;
+	if (!dp)
 		return 0;
 
 	mutex_lock(&register_mutex);
···
 	int rc;
 
 	mutex_lock(&register_mutex);
-	if ((rc = snd_register_oss_device(SNDRV_OSS_DEVICE_TYPE_SEQUENCER,
-					  NULL, 0,
-					  &seq_oss_f_ops, NULL)) < 0) {
+	rc = snd_register_oss_device(SNDRV_OSS_DEVICE_TYPE_SEQUENCER,
+				     NULL, 0,
+				     &seq_oss_f_ops, NULL);
+	if (rc < 0) {
 		pr_err("ALSA: seq_oss: can't register device seq\n");
 		mutex_unlock(&register_mutex);
 		return rc;
 	}
-	if ((rc = snd_register_oss_device(SNDRV_OSS_DEVICE_TYPE_MUSIC,
-					  NULL, 0,
-					  &seq_oss_f_ops, NULL)) < 0) {
+	rc = snd_register_oss_device(SNDRV_OSS_DEVICE_TYPE_MUSIC,
+				     NULL, 0,
+				     &seq_oss_f_ops, NULL);
+	if (rc < 0) {
 		pr_err("ALSA: seq_oss: can't register device music\n");
 		snd_unregister_oss_device(SNDRV_OSS_DEVICE_TYPE_SEQUENCER, NULL, 0);
 		mutex_unlock(&register_mutex);

sound/core/seq/oss/seq_oss_init.c

···
 	port->kernel = &port_callback;
 	
 	call_ctl(SNDRV_SEQ_IOCTL_CREATE_PORT, port);
-	if ((system_port = port->addr.port) >= 0) {
+	system_port = port->addr.port;
+	if (system_port >= 0) {
 		struct snd_seq_port_subscribe subs;
 
 		memset(&subs, 0, sizeof(subs));
···
 	qinfo.owner = system_client;
 	qinfo.locked = 1;
 	strcpy(qinfo.name, "OSS Sequencer Emulation");
-	if ((rc = call_ctl(SNDRV_SEQ_IOCTL_CREATE_QUEUE, &qinfo)) < 0)
+	rc = call_ctl(SNDRV_SEQ_IOCTL_CREATE_QUEUE, &qinfo);
+	if (rc < 0)
 		return rc;
 	dp->queue = qinfo.queue;
 	return 0;
···
 	snd_iprintf(buf, "\nNumber of applications: %d\n", num_clients);
 	for (i = 0; i < num_clients; i++) {
 		snd_iprintf(buf, "\nApplication %d: ", i);
-		if ((dp = client_table[i]) == NULL) {
+		dp = client_table[i];
+		if (!dp) {
 			snd_iprintf(buf, "*empty*\n");
 			continue;
 		}

sound/core/seq/oss/seq_oss_midi.c

···
 	/*
 	 * look for the identical slot
 	 */
-	if ((mdev = find_slot(pinfo->addr.client, pinfo->addr.port)) != NULL) {
+	mdev = find_slot(pinfo->addr.client, pinfo->addr.port);
+	if (mdev) {
 		/* already exists */
 		snd_use_lock_free(&mdev->use_lock);
 		return 0;
···
 	unsigned long flags;
 	int index;
 
-	if ((mdev = find_slot(client, port)) != NULL) {
+	mdev = find_slot(client, port);
+	if (mdev) {
 		spin_lock_irqsave(&register_lock, flags);
 		midi_devs[mdev->seq_device] = NULL;
 		spin_unlock_irqrestore(&register_lock, flags);
···
 
 	spin_lock_irqsave(&register_lock, flags);
 	for (i = 0; i < max_midi_devs; i++) {
-		if ((mdev = midi_devs[i]) != NULL) {
+		mdev = midi_devs[i];
+		if (mdev) {
 			snd_midi_event_free(mdev->coder);
 			kfree(mdev);
 			midi_devs[i] = NULL;
···
 	struct seq_oss_midi *mdev;
 	struct snd_seq_port_subscribe subs;
 
-	if ((mdev = get_mididev(dp, dev)) == NULL)
+	mdev = get_mididev(dp, dev);
+	if (!mdev)
 		return -ENODEV;
 
 	/* already used? */
···
 	struct seq_oss_midi *mdev;
 	struct snd_seq_port_subscribe subs;
 
-	if ((mdev = get_mididev(dp, dev)) == NULL)
+	mdev = get_mididev(dp, dev);
+	if (!mdev)
 		return -ENODEV;
 	if (! mdev->opened || mdev->devinfo != dp) {
 		snd_use_lock_free(&mdev->use_lock);
···
 	struct seq_oss_midi *mdev;
 	int mode;
 
-	if ((mdev = get_mididev(dp, dev)) == NULL)
+	mdev = get_mididev(dp, dev);
+	if (!mdev)
 		return 0;
 
 	mode = 0;
···
 {
 	struct seq_oss_midi *mdev;
 
-	if ((mdev = get_mididev(dp, dev)) == NULL)
+	mdev = get_mididev(dp, dev);
+	if (!mdev)
 		return;
 	if (! mdev->opened) {
 		snd_use_lock_free(&mdev->use_lock);
···
 {
 	struct seq_oss_midi *mdev;
 
-	if ((mdev = get_mididev(dp, dev)) == NULL)
+	mdev = get_mididev(dp, dev);
+	if (!mdev)
 		return;
 	addr->client = mdev->client;
 	addr->port = mdev->port;
···
 
 	if (dp->readq == NULL)
 		return 0;
-	if ((mdev = find_slot(ev->source.client, ev->source.port)) == NULL)
+	mdev = find_slot(ev->source.client, ev->source.port);
+	if (!mdev)
 		return 0;
 	if (! (mdev->opened & PERM_READ)) {
 		snd_use_lock_free(&mdev->use_lock);
···
 {
 	struct seq_oss_midi *mdev;
 
-	if ((mdev = get_mididev(dp, dev)) == NULL)
+	mdev = get_mididev(dp, dev);
+	if (!mdev)
 		return -ENODEV;
 	if (snd_midi_event_encode_byte(mdev->coder, c, ev)) {
 		snd_seq_oss_fill_addr(dp, ev, mdev->client, mdev->port);
···
 {
 	struct seq_oss_midi *mdev;
 
-	if ((mdev = get_mididev(dp, dev)) == NULL)
+	mdev = get_mididev(dp, dev);
+	if (!mdev)
 		return -ENXIO;
 	inf->device = dev;
 	inf->dev_type = 0; /* FIXME: ?? */

sound/core/seq/oss/seq_oss_rw.c

···
 		}
 
 		/* insert queue */
-		if ((err = insert_queue(dp, &rec, opt)) < 0)
+		err = insert_queue(dp, &rec, opt);
+		if (err < 0)
 			break;
 
 		result += ev_size;

sound/core/seq/oss/seq_oss_synth.c

···
 
 	if (info->is_midi)
 		return 0;
-	if ((rec = get_synthdev(dp, dev)) == NULL)
+	rec = get_synthdev(dp, dev);
+	if (!rec)
 		return -ENXIO;
 
 	if (rec->oper.load_patch == NULL)
···
 	info = get_synthinfo_nospec(dp, dev);
 	if (!info || info->is_midi)
 		return -ENXIO;
-	if ((rec = get_synthdev(dp, dev)) == NULL)
+	rec = get_synthdev(dp, dev);
+	if (!rec)
 		return -ENXIO;
 	if (rec->oper.ioctl == NULL)
 		rc = -ENXIO;
···
 		inf->device = dev;
 		strscpy(inf->name, minf.name, sizeof(inf->name));
 	} else {
-		if ((rec = get_synthdev(dp, dev)) == NULL)
+		rec = get_synthdev(dp, dev);
+		if (!rec)
 			return -ENXIO;
 		inf->synth_type = rec->synth_type;
 		inf->synth_subtype = rec->synth_subtype;

sound/core/seq/oss/seq_oss_writeq.c

···
 	struct seq_oss_writeq *q;
 	struct snd_seq_client_pool pool;
 
-	if ((q = kzalloc(sizeof(*q), GFP_KERNEL)) == NULL)
+	q = kzalloc(sizeof(*q), GFP_KERNEL);
+	if (!q)
 		return NULL;
 	q->dp = dp;
 	q->maxlen = maxlen;

sound/core/seq/seq_clientmgr.c

···
 	if (snd_BUG_ON(!client))
 		return -ENXIO;
 
-	if (!client->accept_input || (fifo = client->data.user.fifo) == NULL)
+	if (!client->accept_input)
+		return -ENXIO;
+	fifo = client->data.user.fifo;
+	if (!fifo)
 		return -ENXIO;
 
 	if (atomic_read(&fifo->overflow) > 0) {
···
 		int nonblock;
 
 		nonblock = (file->f_flags & O_NONBLOCK) || result > 0;
-		if ((err = snd_seq_fifo_cell_out(fifo, &cell, nonblock)) < 0) {
+		err = snd_seq_fifo_cell_out(fifo, &cell, nonblock);
+		if (err < 0)
 			break;
-		}
 		if (snd_seq_ev_is_variable(&cell->event)) {
 			struct snd_seq_event tmpev;
 			tmpev = cell->event;
···
 		return err;
 
 	/* we got a cell. enqueue it. */
-	if ((err = snd_seq_enqueue_event(cell, atomic, hop)) < 0) {
+	err = snd_seq_enqueue_event(cell, atomic, hop);
+	if (err < 0) {
 		snd_seq_cell_free(cell);
 		return err;
 	}
···
 		return -EINVAL;
 	}
 	if (client->type == KERNEL_CLIENT) {
-		if ((callback = info->kernel) != NULL) {
+		callback = info->kernel;
+		if (callback) {
 			if (callback->owner)
 				port->owner = callback->owner;
 			port->private_data = callback->private_data;
···
 	struct snd_seq_client *receiver = NULL, *sender = NULL;
 	struct snd_seq_client_port *sport = NULL, *dport = NULL;
 
-	if ((receiver = snd_seq_client_use_ptr(subs->dest.client)) == NULL)
+	receiver = snd_seq_client_use_ptr(subs->dest.client);
+	if (!receiver)
 		goto __end;
-	if ((sender = snd_seq_client_use_ptr(subs->sender.client)) == NULL)
+	sender = snd_seq_client_use_ptr(subs->sender.client);
+	if (!sender)
 		goto __end;
-	if ((sport = snd_seq_port_use_ptr(sender, subs->sender.port)) == NULL)
+	sport = snd_seq_port_use_ptr(sender, subs->sender.port);
+	if (!sport)
 		goto __end;
-	if ((dport = snd_seq_port_use_ptr(receiver, subs->dest.port)) == NULL)
+	dport = snd_seq_port_use_ptr(receiver, subs->dest.port);
+	if (!dport)
 		goto __end;
 
 	result = check_subscription_permission(client, sport, dport, subs);
···
 	struct snd_seq_client *receiver = NULL, *sender = NULL;
 	struct snd_seq_client_port *sport = NULL, *dport = NULL;
 
-	if ((receiver = snd_seq_client_use_ptr(subs->dest.client)) == NULL)
+	receiver = snd_seq_client_use_ptr(subs->dest.client);
+	if (!receiver)
 		goto __end;
-	if ((sender = snd_seq_client_use_ptr(subs->sender.client)) == NULL)
+	sender = snd_seq_client_use_ptr(subs->sender.client);
+	if (!sender)
 		goto __end;
-	if ((sport = snd_seq_port_use_ptr(sender, subs->sender.port)) == NULL)
+	sport = snd_seq_port_use_ptr(sender, subs->sender.port);
+	if (!sport)
 		goto __end;
-	if ((dport = snd_seq_port_use_ptr(receiver, subs->dest.port)) == NULL)
+	dport = snd_seq_port_use_ptr(receiver, subs->dest.port);
+	if (!dport)
 		goto __end;
 
 	result = check_subscription_permission(client, sport, dport, subs);
···
 	struct snd_seq_client_port *sport = NULL;
 
 	result = -EINVAL;
-	if ((sender = snd_seq_client_use_ptr(subs->sender.client)) == NULL)
+	sender = snd_seq_client_use_ptr(subs->sender.client);
+	if (!sender)
 		goto __end;
-	if ((sport = snd_seq_port_use_ptr(sender, subs->sender.port)) == NULL)
+	sport = snd_seq_port_use_ptr(sender, subs->sender.port);
+	if (!sport)
 		goto __end;
 	result = snd_seq_port_get_subscription(&sport->c_src, &subs->dest,
 					       subs);
···
 	struct list_head *p;
 	int i;
 
-	if ((cptr = snd_seq_client_use_ptr(subs->root.client)) == NULL)
+	cptr = snd_seq_client_use_ptr(subs->root.client);
+	if (!cptr)
 		goto __end;
-	if ((port = snd_seq_port_use_ptr(cptr, subs->root.port)) == NULL)
+	port = snd_seq_port_use_ptr(cptr, subs->root.port);
+	if (!port)
 		goto __end;
 
 	switch (subs->type) {

sound/core/seq/seq_dummy.c

···
 	struct snd_seq_port_callback pcb;
 	struct snd_seq_dummy_port *rec;
 
-	if ((rec = kzalloc(sizeof(*rec), GFP_KERNEL)) == NULL)
+	rec = kzalloc(sizeof(*rec), GFP_KERNEL);
+	if (!rec)
 		return NULL;
 
 	rec->client = my_client;

sound/core/seq/seq_fifo.c

···
 {
 	struct snd_seq_event_cell *cell;
 
-	if ((cell = f->head) != NULL) {
+	cell = f->head;
+	if (cell) {
 		f->head = cell->next;
 
 		/* reset tail if this was the last element */

sound/core/seq/seq_memory.c

···
 	int len, err;
 	struct snd_seq_event_cell *cell;
 
-	if ((len = get_var_len(event)) <= 0)
+	len = get_var_len(event);
+	if (len <= 0)
 		return len;
 
 	if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {
···
 	int len, newlen;
 	int err;
 
-	if ((len = get_var_len(event)) < 0)
+	len = get_var_len(event);
+	if (len < 0)
 		return len;
 	newlen = len;
 	if (size_aligned > 0)

sound/core/seq/seq_midi.c

···
 	if (snd_BUG_ON(!substream || !buf))
 		return -EINVAL;
 	runtime = substream->runtime;
-	if ((tmp = runtime->avail) < count) {
+	tmp = runtime->avail;
+	if (tmp < count) {
 		if (printk_ratelimit())
 			pr_err("ALSA: seq_midi: MIDI output buffer overrun\n");
 		return -ENOMEM;
···
 	struct snd_rawmidi_params params;
 
 	/* open midi port */
-	if ((err = snd_rawmidi_kernel_open(msynth->card, msynth->device,
-					   msynth->subdevice,
-					   SNDRV_RAWMIDI_LFLG_INPUT,
-					   &msynth->input_rfile)) < 0) {
+	err = snd_rawmidi_kernel_open(msynth->card, msynth->device,
+				      msynth->subdevice,
+				      SNDRV_RAWMIDI_LFLG_INPUT,
+				      &msynth->input_rfile);
+	if (err < 0) {
 		pr_debug("ALSA: seq_midi: midi input open failed!!!\n");
 		return err;
 	}
···
 	memset(&params, 0, sizeof(params));
 	params.avail_min = 1;
 	params.buffer_size = input_buffer_size;
-	if ((err = snd_rawmidi_input_params(msynth->input_rfile.input, &params)) < 0) {
+	err = snd_rawmidi_input_params(msynth->input_rfile.input, &params);
+	if (err < 0) {
 		snd_rawmidi_kernel_release(&msynth->input_rfile);
 		return err;
 	}
···
 	struct snd_rawmidi_params params;
 
 	/* open midi port */
-	if ((err = snd_rawmidi_kernel_open(msynth->card, msynth->device,
-					   msynth->subdevice,
-					   SNDRV_RAWMIDI_LFLG_OUTPUT,
-					   &msynth->output_rfile)) < 0) {
+	err = snd_rawmidi_kernel_open(msynth->card, msynth->device,
+				      msynth->subdevice,
+				      SNDRV_RAWMIDI_LFLG_OUTPUT,
+				      &msynth->output_rfile);
+	if (err < 0) {
 		pr_debug("ALSA: seq_midi: midi output open failed!!!\n");
 		return err;
 	}
···
 	params.avail_min = 1;
 	params.buffer_size = output_buffer_size;
 	params.no_active_sensing = 1;
-	if ((err = snd_rawmidi_output_params(msynth->output_rfile.output, &params)) < 0) {
+	err = snd_rawmidi_output_params(msynth->output_rfile.output, &params);
+	if (err < 0) {
 		snd_rawmidi_kernel_release(&msynth->output_rfile);
 		return err;
 	}

sound/core/seq/seq_queue.c

···
 	struct snd_seq_queue *q;
 
 	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
-		if ((q = queueptr(i)) != NULL) {
+		q = queueptr(i);
+		if (q) {
 			if (strncmp(q->name, name, sizeof(q->name)) == 0)
 				return q;
 			queuefree(q);
···
 	if (queue == NULL)
 		return -EINVAL;
 	tmr = queue->timer;
-	if ((result = snd_seq_timer_open(queue)) < 0) {
+	result = snd_seq_timer_open(queue);
+	if (result < 0) {
 		snd_seq_timer_defaults(tmr);
 		result = snd_seq_timer_open(queue);
 	}
···
 
 	/* delete own queues from queue list */
 	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
-		if ((q = queue_list_remove(i, client)) != NULL)
+		q = queue_list_remove(i, client);
+		if (q)
 			queue_delete(q);
 	}
 
···
 	 * they are not owned by this client
 	 */
 	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
-		if ((q = queueptr(i)) == NULL)
+		q = queueptr(i);
+		if (!q)
 			continue;
 		if (test_bit(client, q->clients_bitmap)) {
 			snd_seq_prioq_leave(q->tickq, client, 0);
···
 	struct snd_seq_queue *q;
 
 	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
-		if ((q = queueptr(i)) == NULL)
+		q = queueptr(i);
+		if (!q)
 			continue;
 		snd_seq_prioq_leave(q->tickq, client, 0);
 		snd_seq_prioq_leave(q->timeq, client, 0);
···
 	struct snd_seq_queue *q;
 
 	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
-		if ((q = queueptr(i)) == NULL)
+		q = queueptr(i);
+		if (!q)
 			continue;
 		if (test_bit(client, q->clients_bitmap) &&
 		    (! (info->remove_mode & SNDRV_SEQ_REMOVE_DEST) ||
···
 	int owner;
 
 	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
-		if ((q = queueptr(i)) == NULL)
+		q = queueptr(i);
+		if (!q)
 			continue;
 
 		tmr = q->timer;

sound/core/seq/seq_virmidi.c

···
 	int err;
 	
 	*rrmidi = NULL;
-	if ((err = snd_rawmidi_new(card, "VirMidi", device,
-				   16,	/* may be configurable */
-				   16,	/* may be configurable */
-				   &rmidi)) < 0)
+	err = snd_rawmidi_new(card, "VirMidi", device,
+			      16,	/* may be configurable */
+			      16,	/* may be configurable */
+			      &rmidi);
+	if (err < 0)
 		return err;
 	strcpy(rmidi->name, rmidi->id);
 	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);