Messages in this thread | | | Date | Fri, 23 Mar 2018 13:04:18 -0400 (EDT) | Subject | Re: [PATCH v5 3/5] bnx2x: Eliminate duplicate barriers on weakly-ordered archs | From | David Miller <> |
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From: Sinan Kaya <okaya@codeaurora.org> Date: Fri, 23 Mar 2018 12:51:47 -0400
> It could if txdata->tx_db was not a union. There is a data dependency > between txdata->tx_db.data.prod and txdata->tx_db.raw. > > So, no reordering.
I don't see it that way, the code requires that:
txdata->tx_db.data.prod += nbd;
is visible before the doorbell update.
barrier() doesn't provide that.
Neither does writel_relaxed(). However plain writel() does.
Therefore the code is only correct as-is, and your change potentially adds a reordering problem.
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