Found using smatch: drivers/dma/at_hdmac.c:299 atc_get_bytes_left() warn: unsigned 'atchan->remain_desc' is never less than zero. Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx> --- drivers/dma/at_hdmac.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index c13a3bb0f594..9ec84ee2fa25 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -294,14 +294,16 @@ static int atc_get_bytes_left(struct dma_chan *chan) ret = -EINVAL; goto out; } - atchan->remain_desc -= (desc_cur->lli.ctrla & ATC_BTSIZE_MAX) - << (desc_first->tx_width); - if (atchan->remain_desc < 0) { + + count = (desc_cur->lli.ctrla & ATC_BTSIZE_MAX) + << (desc_first->tx_width); + if (atchan->remain_desc < count) { ret = -EINVAL; goto out; - } else { - ret = atchan->remain_desc; } + + atchan->remain_desc -= count; + ret = atchan->remain_desc; } else { /* * Get residual bytes when current -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html