dma: dmatest: fix potential sign bug

'cnt' is unsigned, so this code may become wrong in future as
dmatest_add_threads() can return error code:

	cnt = dmatest_add_threads(dtc, DMA_MEMCPY);
	thread_count += cnt > 0 ? cnt : 0;
		        ^^^^^^^

Now it can return only -EINVAL if and only if second argument of
dmatest_add_threads() is not one of DMA_MEMCPY, DMA_XOR, DMA_PQ.
So, now it is not wrong but may become wrong in future.

The semantic patch that finds this problem (many false-positive results):
(http://coccinelle.lip6.fr/)

// <smpl>
@ r1 @
identifier f;
@@
int f(...) { ... }

@@
identifier r1.f;
type T;
unsigned T x;
@@

*x = f(...)
 ...
*x > 0

Signed-off-by: Kulikov Vasiliy <segooon@gmail.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
index 68d58c4..5589358 100644 (file)
--- a/drivers/dma/dmatest.c
+++ b/drivers/dma/dmatest.c
@@ -540,7 +540,7 @@ static int dmatest_add_channel(struct dma_chan *chan)
        struct dmatest_chan     *dtc;
        struct dma_device       *dma_dev = chan->device;
        unsigned int            thread_count = 0;
-       unsigned int            cnt;
+       int cnt;
 
        dtc = kmalloc(sizeof(struct dmatest_chan), GFP_KERNEL);
        if (!dtc) {