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SubjectRe: [PATCH] NVMe: Fix compilation on architecturs without readq/writeq

* Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:

> > u64 val;
> > val = readl(addr);
> > val |= readl(addr+4) << 32;
> >
> > is well-defined and must read the low word first - both at the C level
> > *and* at the CPU level. Anything else would be a bug in the
> > architecture "readl()" implementation or the hardware.
>
> That doesn't make the access atomic to hardware however as a true 64bit
> readq/writeq would be ?
>
> It seems to me the two are not quite the same semantically

Correct, and that's what the:

#include <asm/io-inatomic.h>

line in the driver would express.

Thanks,

Ingo


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