RE: [PATCH] dmaengine: dw-edma: fix unnecessary stack usage

From: Gustavo Pimentel
Date: Fri Jun 21 2019 - 04:21:40 EST


Hi,

On Mon, Jun 17, 2019 at 14:16:45, Arnd Bergmann <arnd@xxxxxxxx> wrote:

> Putting large constant data on the stack causes unnecessary overhead
> and stack usage:
>
> drivers/dma/dw-edma/dw-edma-v0-debugfs.c:285:6: error: stack frame size of 1376 bytes in function 'dw_edma_v0_debugfs_on' [-Werror,-Wframe-larger-than=]

I had that warning at the beginning of the development, that's why I
divided the debugfs entries into several subfunctions. Perhaps my
configuration has configured a bigger stack frame size than your
configuration.

>
> Mark the variable 'static const' in order for the compiler to move it
> into the .rodata section where it does no such harm.

Ok, sounds good.
Thanks.

>
> Fixes: 305aebeff879 ("dmaengine: Add Synopsys eDMA IP version 0 debugfs support")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> drivers/dma/dw-edma/dw-edma-v0-debugfs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
> index affa1ccaf7a0..42739508c0d8 100644
> --- a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
> +++ b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
> @@ -48,7 +48,7 @@ static struct {
> } lim[2][EDMA_V0_MAX_NR_CH];
>
> struct debugfs_entries {
> - char name[24];
> + const char *name;
> dma_addr_t *reg;
> };
>
> --
> 2.20.0