[alsa-devel] [PATCH 2/4] ALSA: rawmidi: Simplify error paths

17 Jul 2018

Apply the standard idiom: rewrite the multiple unlocks in error paths
in the goto-error-and-single-unlock way.
Just a code refactoring, and no functional changes.
Signed-off-by: Takashi Iwai tiwai@suse.de
---
 sound/core/rawmidi.c | 76 +++++++++++++++++++++++---------------------
 1 file changed, 39 insertions(+), 37 deletions(-)

diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index 14dec13ecde9..6b24c2d2dae6 100644
--- a/sound/core/rawmidi.c
+++ b/sound/core/rawmidi.c
@@ -338,22 +338,20 @@ int snd_rawmidi_kernel_open(struct snd_card *card, int device, int subdevice,
    		    int mode, struct snd_rawmidi_file *rfile)
 {
    struct snd_rawmidi *rmidi;
-	int err;
+	int err = 0;
if (snd_BUG_ON(!rfile))
    	return -EINVAL;
mutex_lock(&register_mutex);
    rmidi = snd_rawmidi_search(card, device);
-	if (rmidi == NULL) {
-		mutex_unlock(&register_mutex);
-		return -ENODEV;
-	}
-	if (!try_module_get(rmidi->card->module)) {
-		mutex_unlock(&register_mutex);
-		return -ENXIO;
-	}
+	if (!rmidi)
+		err = -ENODEV;
+	else if (!try_module_get(rmidi->card->module))
+		err = -ENXIO;
    mutex_unlock(&register_mutex);
+	if (err < 0)
+		return err;
mutex_lock(&rmidi->open_mutex);
    err = rawmidi_open_priv(rmidi, subdevice, mode, rfile);
@@ -1581,26 +1579,25 @@ int snd_rawmidi_new(struct snd_card *card, char *id, int device,
    				   &rmidi->streams[SNDRV_RAWMIDI_STREAM_INPUT],
    				   SNDRV_RAWMIDI_STREAM_INPUT,
    				   input_count);
-	if (err < 0) {
-		snd_rawmidi_free(rmidi);
-		return err;
-	}
+	if (err < 0)
+		goto error;
    err = snd_rawmidi_alloc_substreams(rmidi,
    				   &rmidi->streams[SNDRV_RAWMIDI_STREAM_OUTPUT],
    				   SNDRV_RAWMIDI_STREAM_OUTPUT,
    				   output_count);
-	if (err < 0) {
-		snd_rawmidi_free(rmidi);
-		return err;
-	}
+	if (err < 0)
+		goto error;
    err = snd_device_new(card, SNDRV_DEV_RAWMIDI, rmidi, &ops);
-	if (err < 0) {
-		snd_rawmidi_free(rmidi);
-		return err;
-	}
+	if (err < 0)
+		goto error;
+
    if (rrawmidi)
    	*rrawmidi = rmidi;
    return 0;
+
+ error:
+	snd_rawmidi_free(rmidi);
+	return err;
 }
 EXPORT_SYMBOL(snd_rawmidi_new);
@@ -1660,30 +1657,27 @@ static int snd_rawmidi_dev_register(struct snd_device *device)
if (rmidi->device >= SNDRV_RAWMIDI_DEVICES)
    	return -ENOMEM;
+	err = 0;
    mutex_lock(&register_mutex);
-	if (snd_rawmidi_search(rmidi->card, rmidi->device)) {
-		mutex_unlock(&register_mutex);
-		return -EBUSY;
-	}
-	list_add_tail(&rmidi->list, &snd_rawmidi_devices);
+	if (snd_rawmidi_search(rmidi->card, rmidi->device))
+		err = -EBUSY;
+	else
+		list_add_tail(&rmidi->list, &snd_rawmidi_devices);
    mutex_unlock(&register_mutex);
+	if (err < 0)
+		return err;
+
    err = snd_register_device(SNDRV_DEVICE_TYPE_RAWMIDI,
    			  rmidi->card, rmidi->device,
    			  &snd_rawmidi_f_ops, rmidi, &rmidi->dev);
    if (err < 0) {
    	rmidi_err(rmidi, "unable to register\n");
-		mutex_lock(&register_mutex);
-		list_del(&rmidi->list);
-		mutex_unlock(&register_mutex);
-		return err;
+		goto error;
    }
-	if (rmidi->ops && rmidi->ops->dev_register &&
-	    (err = rmidi->ops->dev_register(rmidi)) < 0) {
-		snd_unregister_device(&rmidi->dev);
-		mutex_lock(&register_mutex);
-		list_del(&rmidi->list);
-		mutex_unlock(&register_mutex);
-		return err;
+	if (rmidi->ops && rmidi->ops->dev_register) {
+		err = rmidi->ops->dev_register(rmidi);
+		if (err < 0)
+			goto error_unregister;
    }
 #ifdef CONFIG_SND_OSSEMUL
    rmidi->ossreg = 0;
@@ -1735,6 +1729,14 @@ static int snd_rawmidi_dev_register(struct snd_device *device)
    }
 #endif
    return 0;
+
+ error_unregister:
+	snd_unregister_device(&rmidi->dev);
+ error:
+	mutex_lock(&register_mutex);
+	list_del(&rmidi->list);
+	mutex_unlock(&register_mutex);
+	return err;
 }
static int snd_rawmidi_dev_disconnect(struct snd_device *device)
-- 
2.18.0


    