[PATCH 4/5] drivers/net/ethernet/ti/davinci_cpdma.c: Remove potential NULL dereference

From: Julia Lawall
Date: Tue Aug 14 2012 - 11:50:36 EST


From: Julia Lawall <Julia.Lawall@xxxxxxx>

If the NULL test is necessary, the initialization involving a dereference of
the tested value should be moved after the NULL test.

The sematic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
type T;
expression E;
identifier i,fld;
statement S;
@@

- T i = E->fld;
+ T i;
... when != E
when != i
if (E == NULL) S
+ i = E->fld;
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxx>

---
drivers/net/ethernet/ti/davinci_cpdma.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c b/drivers/net/ethernet/ti/davinci_cpdma.c
index 3b5c457..d15c888 100644
--- a/drivers/net/ethernet/ti/davinci_cpdma.c
+++ b/drivers/net/ethernet/ti/davinci_cpdma.c
@@ -538,11 +538,12 @@ EXPORT_SYMBOL_GPL(cpdma_chan_create);

int cpdma_chan_destroy(struct cpdma_chan *chan)
{
- struct cpdma_ctlr *ctlr = chan->ctlr;
+ struct cpdma_ctlr *ctlr;
unsigned long flags;

if (!chan)
return -EINVAL;
+ ctlr = chan->ctlr;

spin_lock_irqsave(&ctlr->lock, flags);
if (chan->state != CPDMA_STATE_IDLE)

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