linux-kernel - [PATCH v2 1/4] dmaengine: pl330: Remove non-NULL check for pl330_submit

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Date:	Mon, 08 Sep 2014 10:42:47 +0200
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Dan Williams <dan.j.williams@...el.com>,
	Vinod Koul <vinod.koul@...el.com>, dmaengine@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc:	Lars-Peter Clausen <lars@...afoo.de>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>
Subject: [PATCH v2 1/4] dmaengine: pl330: Remove non-NULL check for
 pl330_submit_req parameters

The pl330_submit_req() checked supplied 'struct pl330_thread thrd' and
'struct dma_pl330_desc desc' parameters for non-NULL. However these
checks are useless because supplied arguments won't be NULL.

The pl330_submit_req() is called in only one place and:
1. 'desc' is already dereferenced in fill_queue() before calling
   pl330_submit_req().
2. 'thrd' is always dereferenced after calling
   fill_queue()->pl330_submit_req().

Removing the checks for non-NULL values fixes following warning:
drivers/dma/pl330.c:1376 pl330_submit_req() warn: variable dereferenced before check 'thrd' (see line 1367)

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>

---

Changes since v1:
=================
1. Remove the checks for non-NULL completely instead of moving them
   before dereference. Suggested by Lars-Peter Clausen.
---
 drivers/dma/pl330.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index d5149aacd2fe..57049f84d0c0 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -1372,10 +1372,6 @@ static int pl330_submit_req(struct pl330_thread *thrd,
 	u32 ccr;
 	int ret = 0;
 
-	/* No Req or Unacquired Channel or DMAC */
-	if (!desc || !thrd || thrd->free)
-		return -EINVAL;
-
 	regs = thrd->dmac->base;
 
 	if (pl330->state == DYING
-- 
1.9.1

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