Re: [PATCH] usb: r8a66597-hcd: fix buffer overflow on odd-length FIFO reads

[Karl Mehltretter <kmehltretter@gmail.com>]

Hi Geert,

On Sat, Oct 03, 2026 at 02:42:48PM +0100, Geert Uytterhoeven wrote:
> > +               count = len / 2;
> > +               ioread16_rep(fifoaddr, buf, count);
> 
> Or just:
> 
>     ioread16_rep(fifoaddr, buf, len / 2);
> 
> > +
> > +               if (len & 0x00000001) {
> 
> "len & 1"?
> 

Thanks for suggesting that! I will use len / 2 and len & 1, and a
plain byte store instead of the memcpy().

> 
> Seriously: a *_rep() function for a single iteration?
> 

I'd like to keep this one. ioread16_rep() does not byte swap.
ioread16() goes through readw(), which swaps on big endian on most
architectures.

The words before the last one are read with ioread16_rep(), so reading
the last word the same way puts its first FIFO byte first in memory on
every architecture.

Thanks,
Karl