[PATCH 1/2] dmaengine: xilinx: xdma: Fix operator precedence in xdma_prep_interleaved_dma()
Nathan Chancellor
nathan at kernel.org
Fri Dec 22 10:06:44 PST 2023
Clang warns (or errors with CONFIG_WERROR=y):
drivers/dma/xilinx/xdma.c:757:68: error: operator '?:' has lower precedence than '+'; '+' will be evaluated first [-Werror,-Wparentheses]
757 | src_addr += dmaengine_get_src_icg(xt, &xt->sgl[i]) + xt->src_inc ?
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^
drivers/dma/xilinx/xdma.c:757:68: note: place parentheses around the '+' expression to silence this warning
757 | src_addr += dmaengine_get_src_icg(xt, &xt->sgl[i]) + xt->src_inc ?
| ^
| ( )
drivers/dma/xilinx/xdma.c:757:68: note: place parentheses around the '?:' expression to evaluate it first
757 | src_addr += dmaengine_get_src_icg(xt, &xt->sgl[i]) + xt->src_inc ?
| ^
| (
758 | xt->sgl[i].size : 0;
|
| )
drivers/dma/xilinx/xdma.c:759:68: error: operator '?:' has lower precedence than '+'; '+' will be evaluated first [-Werror,-Wparentheses]
759 | dst_addr += dmaengine_get_dst_icg(xt, &xt->sgl[i]) + xt->dst_inc ?
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^
drivers/dma/xilinx/xdma.c:759:68: note: place parentheses around the '+' expression to silence this warning
759 | dst_addr += dmaengine_get_dst_icg(xt, &xt->sgl[i]) + xt->dst_inc ?
| ^
| ( )
drivers/dma/xilinx/xdma.c:759:68: note: place parentheses around the '?:' expression to evaluate it first
759 | dst_addr += dmaengine_get_dst_icg(xt, &xt->sgl[i]) + xt->dst_inc ?
| ^
| (
760 | xt->sgl[i].size : 0;
|
| )
The src_inc and dst_inc members of 'struct dma_interleaved_template' are
booleans, so it does not make sense for the addition to happen first.
Wrap the conditional operator in parantheses so it is evaluated first.
Closes: https://github.com/ClangBuiltLinux/linux/issues/1971
Fixes: 2f8f90cd2f8d ("dmaengine: xilinx: xdma: Implement interleaved DMA transfers")
Signed-off-by: Nathan Chancellor <nathan at kernel.org>
---
drivers/dma/xilinx/xdma.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/dma/xilinx/xdma.c b/drivers/dma/xilinx/xdma.c
index 4ebc90b41bdb..d5b9fc3fd955 100644
--- a/drivers/dma/xilinx/xdma.c
+++ b/drivers/dma/xilinx/xdma.c
@@ -754,10 +754,10 @@ xdma_prep_interleaved_dma(struct dma_chan *chan,
dst_addr = xt->dst_start;
for (i = 0; i < xt->frame_size; ++i) {
desc_num += xdma_fill_descs(sw_desc, src_addr, dst_addr, xt->sgl[i].size, desc_num);
- src_addr += dmaengine_get_src_icg(xt, &xt->sgl[i]) + xt->src_inc ?
- xt->sgl[i].size : 0;
- dst_addr += dmaengine_get_dst_icg(xt, &xt->sgl[i]) + xt->dst_inc ?
- xt->sgl[i].size : 0;
+ src_addr += dmaengine_get_src_icg(xt, &xt->sgl[i]) + (xt->src_inc ?
+ xt->sgl[i].size : 0);
+ dst_addr += dmaengine_get_dst_icg(xt, &xt->sgl[i]) + (xt->dst_inc ?
+ xt->sgl[i].size : 0);
period_size += xt->sgl[i].size;
}
sw_desc->period_size = period_size;
--
2.43.0
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