On Saturday 19 October 2019 16:24:43 CEST Dan Carpenter wrote:
> On Sat, Oct 19, 2019 at 03:07:15PM +0100, Jules Irenge wrote:
> > diff --git a/drivers/staging/wfx/bh.c b/drivers/staging/wfx/bh.c
> > index 3355183fc86c..573216b08042 100644
> > --- a/drivers/staging/wfx/bh.c
> > +++ b/drivers/staging/wfx/bh.c
> > @@ -69,13 +69,13 @@ static int rx_helper(struct wfx_dev *wdev, size_t read_len, int *is_cnf)
> > if (wfx_data_read(wdev, skb->data, alloc_len))
> > goto err;
> >
> > - piggyback = le16_to_cpup((u16 *) (skb->data + alloc_len - 2));
> > + piggyback = le16_to_cpup((u16 *)(skb->data + alloc_len - 2));
> > _trace_piggyback(piggyback, false);
> >
> > - hif = (struct hif_msg *) skb->data;
> > + hif = (struct hif_msg *)skb->data;
> > WARN(hif->encrypted & 0x1, "unsupported encryption type");
> > if (hif->encrypted == 0x2) {
> > - if (wfx_sl_decode(wdev, (void *) hif)) {
> > + if (wfx_sl_decode(wdev, (void *)hif)) {
>
> In the future you may want to go through and remove the (void *) casts.
> It's not required here.
>
> > diff --git a/drivers/staging/wfx/bus_spi.c b/drivers/staging/wfx/bus_spi.c
> > index f65f7d75e731..effd07957753 100644
> > --- a/drivers/staging/wfx/bus_spi.c
> > +++ b/drivers/staging/wfx/bus_spi.c
> > @@ -90,7 +90,7 @@ static int wfx_spi_copy_to_io(void *priv, unsigned int addr,
> > struct wfx_spi_priv *bus = priv;
> > u16 regaddr = (addr << 12) | (count / 2);
> > // FIXME: use a bounce buffer
> > - u16 *src16 = (void *) src;
> > + u16 *src16 = (void *)src;
>
> Here we are just getting rid of the constness. Apparently we are doing
> that so we can modify it without GCC pointing out the bug!! I don't
> know the code but this seems very wrong.
Hello Dan, Jules,
Indeed, this code should be improved.
Each u16 from src is byte-swapped before to be sent to SPI and restored
before to return from the function:
for (i = 0; i < count / 2; i++)
swab16s(&src16[i]);
[...]
spi_sync(bus->func, &m);
[...]
for (i = 0; i < count / 2; i++)
swab16s(&src16[i]);
So, src is same than original, but it is not const.
This is exactly the purpose of the FIXME just before the cast: "use a
bounce buffer". However, I did not yet make this change because I worry
about a possible performance penalty.
--
Jérôme Pouiller
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