Re: Why is wmb() a no-op on x86_64?

[Bryan O'Sullivan]

On Wed, 2006-01-18 at 12:06 -0500, Jes Sorensen wrote:

> A job for mmiowb() perhaps?

That might be suitable.  It's a no-op on most platforms, but it's only
used by a handful of drivers:

        drivers/scsi/qla1280.c
        drivers/sn/ioc4.c
        drivers/net/bnx2.c
        drivers/net/sky2.c
        drivers/net/s2io.c
        drivers/net/tg3.c

If the semantics were to change so that it really did a write barrier, I
doubt any existing users would notice.  In fact, based on the comments
in some drivers, at least some authors think it does already, when it
typically doesn't.

	<b

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