From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754904AbcGELSM (ORCPT ); Tue, 5 Jul 2016 07:18:12 -0400 Received: from mout.kundenserver.de ([212.227.126.187]:60950 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754095AbcGELSE (ORCPT ); Tue, 5 Jul 2016 07:18:04 -0400 From: Arnd Bergmann To: linux-arm-kernel@lists.infradead.org Cc: Philipp Zabel , linux-kernel@vger.kernel.org, Chen-Yu Tsai , Dinh Nguyen , Steffen Trumtrar , Maxime Ripard Subject: Re: [PATCH 3/3] reset: socfpga: use readl/writel_relaxed Date: Tue, 05 Jul 2016 13:20:29 +0200 Message-ID: <10266400.9nrl73J4sT@wuerfel> User-Agent: KMail/5.1.3 (Linux/4.4.0-22-generic; KDE/5.18.0; x86_64; ; ) In-Reply-To: <1467713872-4051-3-git-send-email-p.zabel@pengutronix.de> References: <1467713872-4051-1-git-send-email-p.zabel@pengutronix.de> <1467713872-4051-3-git-send-email-p.zabel@pengutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:kAAJpAlSyxki2/TSSDxCjl6cj3AVuxT/UNLo72NtxvejJr7QXoW owbjXoJcgb8Pjf9rbcB0vZTmqmsyigWHs+Vbjr5iyntzlnR5/B6BjCRQbfxes56zNp9BwMZ H4xOYme+8nxStFPtvWTDR9aVgs0QUNPqwK5Bp15hLagG4KlVxrvDYz+6/K/fOpUvs/4q5dm mxtltO9FETzzpxWQx0kwA== X-UI-Out-Filterresults: notjunk:1;V01:K0:rXW1PbqX+jE=:Q3eL24B2Hn1lVLe6jRR6jy 6sW1Xsny+HewqZ4dqV9cAdSjK9TFYlqjw6A5x7bxV4vAfRZRbJCu9V6HFA3S9VqX+cwT1DaBN 7isIB9ASxlTuF/XZ1ILHJdOTwHonZGxWaVWjwp1mGRqO+YHVEicdQQXrxGU6jGqLvKv472Zpb QWyCLG36mQdaRRVjYWrZqDNxWjKWhgA8aElFq6EM3LUj7leIlxUaqYP92xARY6m68Y9lMMqYu aq2sLGvFDb+BVP8f8VbNwBGNvordNmoDFlParmZcuLI7ZJ1nWtYKZ1ffTw5OCJF5sgQOi+Xpt X0/Fhzc65FgjD/QvrGHIAjXqGvukz3bOU+2z6I2v2PbY2EbMWByVnJWDcQPmS/L4t/h7hnKs5 lyDr4v9XI+0Cw/mjusSEsUIaDMflomGohRzYKZGkpDjEnZiUMsT3OlUkk3rgATwZC+w0eqTa/ EU4lLKXBBpQhxTd/SgYNcQhOumfSf+I3kaPi0RgwPBU2q59WfdRBv0zZtDJVuk0BY5/e1ImOt D++HBToo+EmQVjbbyo1bQdAuXjNeg3nSvtmsa/BiGWb5/OfzJbXkkwVpkUtFso5Rj6cfCW8b4 aD4TycE/kWCxmpr/3sEJOP+sTy9/EPbL4DUhSrKnTGgQIwWaKx+8lxoazqrGp6ADOysKVHFaz ym/+TS33XwAB6cATBjqt+rOOHuhMLhpyObkX6L8eDeo7tSwr1vKLoWY1maDPARS6gV+pGbRDk jbV3ZO1tjldWmzcl Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, July 5, 2016 12:17:52 PM CEST Philipp Zabel wrote: > This just removes the rmb()/wmb() pair between register read and > write. Since no relevant reads follow the rmb and no relevant writes > precede the wmb, they should be safe to remove. > > Signed-off-by: Philipp Zabel We should only do this if you are fixing a bug (which you don't mention in the changelog), or if you can show a relevant performance improvement. Is this code ever used in a fast path? If it is, wouldn't that indicate a problem in some driver? Arnd