From 97cf56697a31e083c04aa3ec30710f24bbdac86f Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 28 Jan 2015 14:25:10 +0100 Subject: [PATCH] spi/rockchip: avoid uninitialized-use warning We currently get a warning about potentially uninitialized variables in the rockchip spi driver, at least in certain toolchain versions: spi/spi-rockchip.c: In function 'rockchip_spi_prepare_dma': include/linux/dmaengine.h:796:2: warning: 'txdesc' may be used uninitialized in this function include/linux/dmaengine.h:796:2: warning: 'rxdesc' may be used uninitialized in this function The reason seems to be that gcc cannot know whether the value of the rs->rx and rs->tx variables change between the two points these are accessed. The code is actually correct, but to make this clearer to the compiler, this changes the conditionals to test for the local rxdesc/txdesc variables instead, which it knows won't change. Signed-off-by: Arnd Bergmann Signed-off-by: Mark Brown --- drivers/spi/spi-rockchip.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c index daabbabd26b0..1a777dc261d6 100644 --- a/drivers/spi/spi-rockchip.c +++ b/drivers/spi/spi-rockchip.c @@ -437,6 +437,7 @@ static void rockchip_spi_prepare_dma(struct rockchip_spi *rs) rs->state &= ~TXBUSY; spin_unlock_irqrestore(&rs->lock, flags); + rxdesc = NULL; if (rs->rx) { rxconf.direction = rs->dma_rx.direction; rxconf.src_addr = rs->dma_rx.addr; @@ -453,6 +454,7 @@ static void rockchip_spi_prepare_dma(struct rockchip_spi *rs) rxdesc->callback_param = rs; } + txdesc = NULL; if (rs->tx) { txconf.direction = rs->dma_tx.direction; txconf.dst_addr = rs->dma_tx.addr; @@ -470,7 +472,7 @@ static void rockchip_spi_prepare_dma(struct rockchip_spi *rs) } /* rx must be started before tx due to spi instinct */ - if (rs->rx) { + if (rxdesc) { spin_lock_irqsave(&rs->lock, flags); rs->state |= RXBUSY; spin_unlock_irqrestore(&rs->lock, flags); @@ -478,7 +480,7 @@ static void rockchip_spi_prepare_dma(struct rockchip_spi *rs) dma_async_issue_pending(rs->dma_rx.ch); } - if (rs->tx) { + if (txdesc) { spin_lock_irqsave(&rs->lock, flags); rs->state |= TXBUSY; spin_unlock_irqrestore(&rs->lock, flags); -- 2.39.5