From patchwork Sun Jan 10 14:21:39 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 7996931 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 0E6CBBEEE5 for ; Sun, 10 Jan 2016 14:38:13 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2F0FD20204 for ; Sun, 10 Jan 2016 14:38:12 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4AA96201FA for ; Sun, 10 Jan 2016 14:38:11 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1aIH6p-0003Fr-Ew; Sun, 10 Jan 2016 14:36:43 +0000 Received: from mx1.redhat.com ([209.132.183.28]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1aIGsh-0004Ph-Dm for linux-arm-kernel@lists.infradead.org; Sun, 10 Jan 2016 14:22:40 +0000 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (Postfix) with ESMTPS id 9F410C09FA81; Sun, 10 Jan 2016 14:21:47 +0000 (UTC) Received: from redhat.com (vpn1-5-155.ams2.redhat.com [10.36.5.155]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id u0AELdA4032639; Sun, 10 Jan 2016 09:21:40 -0500 Date: Sun, 10 Jan 2016 16:21:39 +0200 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Subject: [PATCH v3 37/41] xenbus: use virt_xxx barriers Message-ID: <1452426622-4471-38-git-send-email-mst@redhat.com> References: <1452426622-4471-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1452426622-4471-1-git-send-email-mst@redhat.com> X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160110_062208_269709_9D217B3A X-CRM114-Status: GOOD ( 14.35 ) X-Spam-Score: -6.9 (------) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-mips@linux-mips.org, linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra , virtualization@lists.linux-foundation.org, "H. Peter Anvin" , sparclinux@vger.kernel.org, Boris Ostrovsky , linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, Russell King - ARM Linux , Arnd Bergmann , x86@kernel.org, xen-devel@lists.xenproject.org, Ingo Molnar , linux-xtensa@linux-xtensa.org, user-mode-linux-devel@lists.sourceforge.net, Stefano Stabellini , adi-buildroot-devel@lists.sourceforge.net, Thomas Gleixner , linux-metag@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Konrad Rzeszutek Wilk , Andrew Cooper , David Vrabel , Joe Perches , linuxppc-dev@lists.ozlabs.org, David Miller Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP drivers/xen/xenbus/xenbus_comms.c uses full memory barriers to communicate with the other side. For guests compiled with CONFIG_SMP, smp_wmb and smp_mb would be sufficient, so mb() and wmb() here are only needed if a non-SMP guest runs on an SMP host. Switch to virt_xxx barriers which serve this exact purpose. Signed-off-by: Michael S. Tsirkin Acked-by: David Vrabel --- drivers/xen/xenbus/xenbus_comms.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/xen/xenbus/xenbus_comms.c b/drivers/xen/xenbus/xenbus_comms.c index fdb0f33..ecdecce 100644 --- a/drivers/xen/xenbus/xenbus_comms.c +++ b/drivers/xen/xenbus/xenbus_comms.c @@ -123,14 +123,14 @@ int xb_write(const void *data, unsigned len) avail = len; /* Must write data /after/ reading the consumer index. */ - mb(); + virt_mb(); memcpy(dst, data, avail); data += avail; len -= avail; /* Other side must not see new producer until data is there. */ - wmb(); + virt_wmb(); intf->req_prod += avail; /* Implies mb(): other side will see the updated producer. */ @@ -180,14 +180,14 @@ int xb_read(void *data, unsigned len) avail = len; /* Must read data /after/ reading the producer index. */ - rmb(); + virt_rmb(); memcpy(data, src, avail); data += avail; len -= avail; /* Other side must not see free space until we've copied out */ - mb(); + virt_mb(); intf->rsp_cons += avail; pr_debug("Finished read of %i bytes (%i to go)\n", avail, len);