dmaengine: sh: don't use dynamic static allocation

dynamic stack allocation in kernel is considered bad as kernel stack is low and we get warns on few archs as reported by kbuild test robot >> drivers/dma/sh/shdma-base.c:671:32: sparse: Variable length array is used. >> drivers/dma/sh/shdma-base.c:701:1: warning: 'shdma_prep_dma_cyclic' uses >> dynamic stack allocation [enabled by default] Fix this by making a static array of 32 which should be sufficient for shdma_prep_dma_cyclic which only user in kernel is audio and 32 periods for audio seems quite sufficient atm Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: sh: don't use dynamic static allocation
dynamic stack allocation in kernel is considered bad as kernel stack is low and we get warns on few archs as reported by kbuild test robot >> drivers/dma/sh/shdma-base.c:671:32: sparse: Variable length array is used. >> drivers/dma/sh/shdma-base.c:701:1: warning: 'shdma_prep_dma_cyclic' uses >> dynamic stack allocation [enabled by default] Fix this by making a static array of 32 which should be sufficient for shdma_prep_dma_cyclic which only user in kernel is audio and 32 periods for audio seems quite sufficient atm Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Vinod Koul
1 parent 9d9f71a804
Showing 1 changed file with 9 additions and 1 deletions Side-by-side Diff
drivers/dma/sh/shdma-base.c
@@ -657,6 +657,8 @@
 			     direction, flags, false);
 }
  
+#define SHDMA_MAX_SG_LEN 32
+
 static struct dma_async_tx_descriptor *shdma_prep_dma_cyclic(
 	struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
 	size_t period_len, enum dma_transfer_direction direction,
  
@@ -668,13 +670,19 @@
 	unsigned int sg_len = buf_len / period_len;
 	int slave_id = schan->slave_id;
 	dma_addr_t slave_addr;
-	struct scatterlist sgl[sg_len];
+	struct scatterlist sgl[SHDMA_MAX_SG_LEN];
 	int i;
  
 	if (!chan)
 		return NULL;
  
 	BUG_ON(!schan->desc_num);
+
+	if (sg_len > SHDMA_MAX_SG_LEN) {
+		dev_err(schan->dev, "sg length %d exceds limit %d",
+				sg_len, SHDMA_MAX_SG_LEN);
+		return NULL;
+	}
  
 	/* Someone calling slave DMA on a generic channel? */
 	if (slave_id < 0 || (buf_len < period_len)) {
...	...	@@ -657,6 +657,8 @@
657	657	direction, flags, false);
658	658	}
659	659
	660	+#define SHDMA_MAX_SG_LEN 32
	661	+
660	662	static struct dma_async_tx_descriptor *shdma_prep_dma_cyclic(
661	663	struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
662	664	size_t period_len, enum dma_transfer_direction direction,
663	665
...	...	@@ -668,13 +670,19 @@
668	670	unsigned int sg_len = buf_len / period_len;
669	671	int slave_id = schan->slave_id;
670	672	dma_addr_t slave_addr;
671		- struct scatterlist sgl[sg_len];
	673	+ struct scatterlist sgl[SHDMA_MAX_SG_LEN];
672	674	int i;
673	675
674	676	if (!chan)
675	677	return NULL;
676	678
677	679	BUG_ON(!schan->desc_num);
	680	+
	681	+ if (sg_len > SHDMA_MAX_SG_LEN) {
	682	+ dev_err(schan->dev, "sg length %d exceds limit %d",
	683	+ sg_len, SHDMA_MAX_SG_LEN);
	684	+ return NULL;
	685	+ }
678	686
679	687	/* Someone calling slave DMA on a generic channel? */
680	688	if (slave_id < 0 \|\| (buf_len < period_len)) {