Re: [PATCH 7/7] libata: Add 32bit PIO support

[Elias Oltmanns <eo@nebensachen.de>]

Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> From: Alan Cox <alan@redhat.com>
>
> This matters for some controllers and in one or two cases almost doubles
> PIO performance. Add a bmdma32 operations set we can inherit and activate
> it for some controllers
>
> Signed-off-by: Alan Cox <alan@redhat.com>
> ---
[...]
> diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
> index 61b1fb4..5c93377 100644
> --- a/drivers/ata/libata-sff.c
> +++ b/drivers/ata/libata-sff.c
[...]
> +	if (unlikely(slop)) {
> +		__le32 pad;
> +		if (rw == READ) {
> +			pad = cpu_to_le32(ioread32(ap->ioaddr.data_addr));
> +			memcpy(buf + buflen - slop, &pad, slop);
> +		} else {
> +			memcpy(&pad, buf + buflen - slop, slop);
> +			iowrite32(le32_to_cpu(pad), ap->ioaddr.data_addr);

Shouldn't the rest of pad be initialised to zero or something before it
is written?

Regards,

Elias