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@xxxxxxxxx>
Signed-off-by: Vinod Koul <vinod.koul@xxxxxxxxx>
---
drivers/dma/sh/shdma-base.c | 10 +++++++++-
1 files changed, 9 insertions(+), 1 deletions(-)
diff --git a/drivers/dma/sh/shdma-base.c b/drivers/dma/sh/shdma-base.c
index 591b9d8..b35007e 100644
--- a/drivers/dma/sh/shdma-base.c
+++ b/drivers/dma/sh/shdma-base.c
@@ -657,6 +657,8 @@ static struct dma_async_tx_descriptor *shdma_prep_slave_sg(
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,
@@ -668,7 +670,7 @@ static struct dma_async_tx_descriptor *shdma_prep_dma_cyclic(
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)
@@ -676,6 +678,12 @@ static struct dma_async_tx_descriptor *shdma_prep_dma_cyclic(
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)) {
dev_warn(schan->dev,
--
1.7.0.4
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