ALSA: seq: virmidi: Use guard() for locking

We can simplify the code gracefully with new guard() macro and co for
automatic cleanup of locks.

Only the code refactoring, and no functional changes.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20240227085306.9764-20-tiwai@suse.de

Author: tiwai

sound/core/seq/seq_virmidi.c

@@ -199,11 +199,10 @@ static int snd_virmidi_input_open(struct snd_rawmidi_substream *substream)
 	vmidi->client = rdev->client;
 	vmidi->port = rdev->port;	
 	runtime->private_data = vmidi;
-	down_write(&rdev->filelist_sem);
-	write_lock_irq(&rdev->filelist_lock);
-	list_add_tail(&vmidi->list, &rdev->filelist);
-	write_unlock_irq(&rdev->filelist_lock);
-	up_write(&rdev->filelist_sem);
+	scoped_guard(rwsem_write, &rdev->filelist_sem) {
+		guard(write_lock_irq)(&rdev->filelist_lock);
+		list_add_tail(&vmidi->list, &rdev->filelist);
+	}
 	vmidi->rdev = rdev;
 	return 0;
 }
@@ -243,11 +242,10 @@ static int snd_virmidi_input_close(struct snd_rawmidi_substream *substream)
 	struct snd_virmidi_dev *rdev = substream->rmidi->private_data;
 	struct snd_virmidi *vmidi = substream->runtime->private_data;
 
-	down_write(&rdev->filelist_sem);
-	write_lock_irq(&rdev->filelist_lock);
-	list_del(&vmidi->list);
-	write_unlock_irq(&rdev->filelist_lock);
-	up_write(&rdev->filelist_sem);
+	scoped_guard(rwsem_write, &rdev->filelist_sem) {
+		guard(write_lock_irq)(&rdev->filelist_lock);
+		list_del(&vmidi->list);
+	}
 	snd_midi_event_free(vmidi->parser);
 	substream->runtime->private_data = NULL;
 	kfree(vmidi);