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Date:   Fri, 23 Mar 2018 12:43:26 -0400 (EDT)
Message-Id: <20180323.124326.2170503491903886041.davem@davemloft.net>
To:     okaya@codeaurora.org
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Subject: Re: [PATCH v5 3/5] bnx2x: Eliminate duplicate barriers on
 weakly-ordered archs
From:   David Miller <davem@davemloft.net>
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From: Sinan Kaya <okaya@codeaurora.org>
Date: Fri, 23 Mar 2018 12:31:12 -0400

> Sorry, you got me confused now.
> 
> If you look at the code closer, you'll see this.
> 
> 	wmb();
> 
> 	txdata->tx_db.data.prod += nbd;
> 	barrier();
> 
> 	DOORBELL(bp, txdata->cid, txdata->tx_db.raw);
> 
> and you also asked me to rename DOORBELL to DOORBELL_RELAXED() to make
> it obvious that we have a relaxed operator inside the macro.

This still doesn't match the stated pattern.

	wmb();
	/* no other memory or I/O or IOMEM operation */
	writel();

There is a write to a producer index there and then no non-compiler
barrier or any kind before the writel().

So, in fact, it might really need that implicit writel() barrier here!