Sep 12 2009

ASoC: Clean up error handling in MPC5200 DMA setup 

Author: Julia Lawall <julia@diku.dk>

Error handling code following a kzalloc should free the allocated data.
Error handling code following an ioremap should iounmap the allocated data.

The semantic match that finds the first problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// 
@r exists@
local idexpression x;
statement S;
expression E;
identifier f,f1,l;
position p1,p2;
expression *ptr != NULL;
@@

x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...);
...
if (x == NULL) S
<... when != x
     when != if (...) { <+...x...+> }
(
x->f1 = E
|
 (x->f1 == NULL || ...)
|
 f(...,x->f1,...)
)
...>
(
 return \(0\|<+...x...+>\|ptr\);
|
 return@p2 ...;
)

@script:python@
p1 << r.p1;
p2 << r.p2;
@@

print "* file: %s kmalloc %s return %s" % (p1[0].file,p1[0].line,p2[0].line)
// 

Signed-off-by: Julia Lawall 
Signed-off-by: Mark Brown 

---
 sound/soc/fsl/mpc5200_dma.c | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)
 
diff --git a/sound/soc/fsl/mpc5200_dma.c b/sound/soc/fsl/mpc5200_dma.c
index 9ff62e3..6096d22 100644
--- a/sound/soc/fsl/mpc5200_dma.c
+++ b/sound/soc/fsl/mpc5200_dma.c
@@ -447,6 +447,7 @@ int mpc5200_audio_dma_create(struct of_device *op)
 	int size, irq, rc;
 	const __be32 *prop;
 	void __iomem *regs;
+	int ret;
 
 	/* Fetch the registers and IRQ of the PSC */
 	irq = irq_of_parse_and_map(op->node, 0);
@@ -463,14 +464,16 @@ int mpc5200_audio_dma_create(struct of_device *op)
 	/* Allocate and initialize the driver private data */
 	psc_dma = kzalloc(sizeof *psc_dma, GFP_KERNEL);
 	if (!psc_dma) {
-		iounmap(regs);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto out_unmap;
 	}
 
 	/* Get the PSC ID */
 	prop = of_get_property(op->node, "cell-index", &size);
-	if (!prop || size < sizeof *prop)
-		return -ENODEV;
+	if (!prop || size < sizeof *prop) {
+		ret = -ENODEV;
+		goto out_free;
+	}
 
 	spin_lock_init(&psc_dma->lock);
 	mutex_init(&psc_dma->mutex);
@@ -493,9 +496,8 @@ int mpc5200_audio_dma_create(struct of_device *op)
 	if (!psc_dma->capture.bcom_task ||
 	    !psc_dma->playback.bcom_task) {
 		dev_err(&op->dev, "Could not allocate bestcomm tasks\n");
-		iounmap(regs);
-		kfree(psc_dma);
-		return -ENODEV;
+		ret = -ENODEV;
+		goto out_free;
 	}
 
 	/* Disable all interrupts and reset the PSC */
@@ -537,12 +539,8 @@ int mpc5200_audio_dma_create(struct of_device *op)
 			  &psc_dma_bcom_irq_tx, IRQF_SHARED,
 			  "psc-dma-playback", &psc_dma->playback);
 	if (rc) {
-		free_irq(psc_dma->irq, psc_dma);
-		free_irq(psc_dma->capture.irq,
-			 &psc_dma->capture);
-		free_irq(psc_dma->playback.irq,
-			 &psc_dma->playback);
-		return -ENODEV;
+		ret = -ENODEV;
+		goto out_irq;
 	}
 
 	/* Save what we've done so it can be found again later */
@@ -550,6 +548,15 @@ int mpc5200_audio_dma_create(struct of_device *op)
 
 	/* Tell the ASoC OF helpers about it */
 	return snd_soc_register_platform(&mpc5200_audio_dma_platform);
+out_irq:
+	free_irq(psc_dma->irq, psc_dma);
+	free_irq(psc_dma->capture.irq, &psc_dma->capture);
+	free_irq(psc_dma->playback.irq, &psc_dma->playback);
+out_free:
+	kfree(psc_dma);
+out_unmap:
+	iounmap(regs);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(mpc5200_audio_dma_create);

qlambert