ALSA: sound: Move dereference after NULL test and drop unnecessary NULL tests

In pcm.c, if the NULL test on pcm is needed, then the dereference should be
after the NULL test.

In dummy.c and ali5451.c, the context of the calls to
snd_card_dummy_new_mixer and snd_ali_free_voice show that dummy and pvoice,
respectively cannot be NULL.

A simplified version of the semantic match that detects this problem is as
follows (http://coccinelle.lip6.fr/):

// <smpl>
@match exists@
expression x, E;
identifier fld;
@@

* x->fld
  ... when != \(x = E\|&x\)
* x == NULL
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index 0c1440121c22c2f4ed8df37615c1241c17c5314e..c69c60b2a48ab9e55f1b90575c92541e0226e849 100644 (file)
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -953,11 +953,12 @@ static int snd_pcm_dev_register(struct snd_device *device)
        struct snd_pcm_substream *substream;
        struct snd_pcm_notify *notify;
        char str[16];
-       struct snd_pcm *pcm = device->device_data;
+       struct snd_pcm *pcm;
        struct device *dev;
 
-       if (snd_BUG_ON(!pcm || !device))
+       if (snd_BUG_ON(!device || !device->device_data))
                return -ENXIO;
+       pcm = device->device_data;
        mutex_lock(&register_mutex);
        err = snd_pcm_add(pcm);
        if (err) {

diff --git a/sound/drivers/dummy.c b/sound/drivers/dummy.c
index 6ba066c41d2e9bd5ab8d7c8e6f1eba438bda62af..146ef00f94a3d31028a919932a688d809f078091 100644 (file)
--- a/sound/drivers/dummy.c
+++ b/sound/drivers/dummy.c
@@ -808,8 +808,6 @@ static int __devinit snd_card_dummy_new_mixer(struct snd_dummy *dummy)
        unsigned int idx;
        int err;
 
-       if (snd_BUG_ON(!dummy))
-               return -EINVAL;
        spin_lock_init(&dummy->mixer_lock);
        strcpy(card->mixername, "Dummy Mixer");
 

diff --git a/sound/pci/ali5451/ali5451.c b/sound/pci/ali5451/ali5451.c
index b458d208720b1c6ac010ab235e122e3dd407f6e5..aaf4da68969c4572c9201e06f8ddc47cbd711f60 100644 (file)
--- a/sound/pci/ali5451/ali5451.c
+++ b/sound/pci/ali5451/ali5451.c
@@ -973,7 +973,7 @@ static void snd_ali_free_voice(struct snd_ali * codec,
        void *private_data;
 
        snd_ali_printk("free_voice: channel=%d\n",pvoice->number);
-       if (pvoice == NULL || !pvoice->use)
+       if (!pvoice->use)
                return;
        snd_ali_clear_voices(codec, pvoice->number, pvoice->number);
        spin_lock_irq(&codec->voice_alloc);