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SubjectRe: [PATCH net] sfc: Reduce RX scatter buffer size to multiple of 256
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On Mon, May 13, 2013 at 9:11 PM, Ben Hutchings
<bhutchings@solarflare.com> wrote:
>> error: BUILD_BUG_ON failed: sizeof(struct efx_rx_page_state) +
>> EFX_PAGE_IP_ALIGN + EFX_RX_USR_BUF_SIZE > PAGE_SIZE / 2
>> make[4]: *** [drivers/net/ethernet/sfc/efx.o] Error 1
>
> OK, this doesn't work because on s390 EFX_PAGE_IP_ALIGN == 2 (this macro

Yeah, that's what I just discovered, too.

#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
#define EFX_PAGE_IP_ALIGN 0
#else
#define EFX_PAGE_IP_ALIGN NET_IP_ALIGN
#endif

> is equivalent to NET_IP_ALIGN, though that wasn't always true). So DMA
> is going to be misaligned on s390 anyway.

Hmm, so it's making the choice between misaligned CPU and misaligned
DMA? Sounds fishy...

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds


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