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Subject[PATCH 2/3] drivers/dma: Remove potential NULL dereference
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In each case, it appears that the NULL test is not necessary.  In the first
case, the function pl08x_fill_llis_for_desc is only called in a case where
its argument is computed using container_of. In the second case, the
function pl08x_tasklet is only used as the second argument of tasklet_init,
from which its argument should be the third argument of tasklet_init. But
that value is not NULL at the point of calling tasklet_init, in
pl08x_dma_init_virtual_channels.

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@diku.dk>

---
drivers/dma/amba-pl08x.c | 8 --------
1 file changed, 8 deletions(-)

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index fc5aaeb..ac675d2 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -626,11 +626,6 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
struct lli *llis_va;
struct lli *llis_bus;

- if (!txd) {
- dev_err(&pl08x->adev->dev, "%s no descriptor\n", __func__);
- return 0;
- }
-
txd->llis_va = dma_pool_alloc(pl08x->pool, GFP_KERNEL,
&txd->llis_bus);
if (!txd->llis_va) {
@@ -1033,9 +1028,6 @@ static void pl08x_tasklet(unsigned long data)
struct pl08x_driver_data *pl08x = plchan->host;
unsigned long flags;

- if (!plchan)
- BUG();
-
spin_lock_irqsave(&plchan->lock, flags);

if (plchan->at) {


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