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From: David Miller <davem@davemloft.net>
To: okaya@codeaurora.org
Cc: netdev@vger.kernel.org, timur@codeaurora.org,
	sulrich@codeaurora.org, linux-arm-msm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, ariel.elior@cavium.com,
	everest-linux-l2@cavium.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 3/5] bnx2x: Eliminate duplicate barriers on weakly-ordered archs
Date: Fri, 23 Mar 2018 12:43:26 -0400 (EDT)	[thread overview]
Message-ID: <20180323.124326.2170503491903886041.davem@davemloft.net> (raw)
In-Reply-To: <cb6a0522-2c53-b252-49db-5779d24963c6@codeaurora.org>

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!

  reply	other threads:[~2018-03-23 16:43 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1521738603-23596-1-git-send-email-okaya@codeaurora.org>
2018-03-22 17:09 ` [PATCH v5 1/5] net: qla3xxx: Eliminate duplicate barriers on weakly-ordered archs Sinan Kaya
2018-03-22 17:09 ` [PATCH v5 2/5] qlcnic: " Sinan Kaya
2018-03-22 17:10 ` [PATCH v5 3/5] bnx2x: " Sinan Kaya
2018-03-23 16:20   ` David Miller
2018-03-23 16:31     ` Sinan Kaya
2018-03-23 16:43       ` David Miller [this message]
2018-03-23 16:51         ` Sinan Kaya
2018-03-23 17:04           ` David Miller
2018-03-23 17:13             ` Sinan Kaya
2018-03-23 17:16               ` David Miller
2018-03-24 14:30               ` Chopra, Manish
2018-03-24 14:57                 ` Sinan Kaya
2018-03-22 17:10 ` [PATCH v5 4/5] net: qlge: " Sinan Kaya
2018-03-22 17:10 ` [PATCH v5 5/5] bnxt_en: " Sinan Kaya

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