From: Linus Torvalds
> Sent: 22 November 2018 18:58
...
> Oh, and I just noticed that on x86 we expressly use our old "safe and
> sane" functions: see __inline_memcpy(), and its use in
> __memcpy_{from,to}io().
>
> So the "falls back to memcpy" was always a red herring. We don't
> actually do that.
>
> Which explains why things work.
It doesn't explain why I've seen single byte PCIe TLP generated
by memcpy_to/fromio().
I've had to change code to use readq/writeq loops because the
byte accesses are so slow - even when PIO performance should
be 'good enough'.
It might have been changed since last time I tested it.
But I don't remember seeing a commit go by.
David
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