From patchwork Fri Oct 26 13:48:09 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Saenz Julienne X-Patchwork-Id: 10657399 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 83A5B13BF for ; Fri, 26 Oct 2018 14:04:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6E2A62C6A5 for ; Fri, 26 Oct 2018 14:04:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5F01B2C6B9; Fri, 26 Oct 2018 14:04:51 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id E275F2C6A5 for ; Fri, 26 Oct 2018 14:04:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=AWGGJXbSs/s6X1zw3KBDhDEJBX+5UF3HTiBSpNH8DQE=; b=YgbK8Nk27KRtYb tced/hUPI4LyqWmyPTJiRvEYC0DLtgPcgjZxcdTPSLh4SLCKHeWauqPiMowAAVxadh9bMkfZP8RiN iC2r/OFuyz+Eh489ZdzqD2FZgwLa+5qeCHKarECR6w767/S3tjbVRU3m0JQSlxr0dPMzUZ47TNGBa FaMJP8rleMrHTtEaB7jWqJX6Xm96KfcVrlWHiRX8lWfSPEMo568Rezb/Pn0UTZJbBW0HbplkSJVUn tTkvN6Wne3Ud9THSwCdrYTNzErponzH9bmC4NRwD+wpsge8EdsuIwy/xBjG0rYwz338w6IRD+baNF xRcCdQd509onkZnbf1YA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gG2jE-0004rS-N2; Fri, 26 Oct 2018 14:04:44 +0000 Received: from mx2.suse.de ([195.135.220.15] helo=mx1.suse.de) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gG2Tu-0002Za-Gy; Fri, 26 Oct 2018 13:49:09 +0000 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 46287B054; Fri, 26 Oct 2018 13:48:38 +0000 (UTC) From: Nicolas Saenz Julienne To: stefan.wahren@i2se.com, eric@anholt.net, dave.stevenson@raspberrypi.org Subject: [PATCH RFC 14/18] staging: vchiq_util: get rid of unneeded memory barriers Date: Fri, 26 Oct 2018 15:48:09 +0200 Message-Id: <20181026134813.7775-15-nsaenzjulienne@suse.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181026134813.7775-1-nsaenzjulienne@suse.de> References: <20181026134813.7775-1-nsaenzjulienne@suse.de> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181026_064854_755638_D626F67D X-CRM114-Status: UNSURE ( 9.53 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devel@driverdev.osuosl.org, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, nsaenzjulienne@suse.de, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP All the memory operations featured in this file modify/access memory that is only accessed by the CPU. So we can assume that all the memory barrier handling done by the completion routines is good enough for us. Signed-off-by: Nicolas Saenz Julienne --- .../interface/vchiq_arm/vchiq_util.c | 32 ------------------- 1 file changed, 32 deletions(-) diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_util.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_util.c index 44b954daa74a..4b8554bc647e 100644 --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_util.c +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_util.c @@ -84,20 +84,7 @@ void vchiu_queue_push(VCHIU_QUEUE_T *queue, VCHIQ_HEADER_T *header) flush_signals(current); } - /* - * Write to queue->storage must be visible after read from - * queue->read - */ - smp_mb(); - queue->storage[queue->write & (queue->size - 1)] = header; - - /* - * Write to queue->storage must be visible before write to - * queue->write - */ - smp_wmb(); - queue->write++; complete(&queue->push); @@ -112,12 +99,6 @@ VCHIQ_HEADER_T *vchiu_queue_peek(VCHIU_QUEUE_T *queue) complete(&queue->push); // We haven't removed anything from the queue. - /* - * Read from queue->storage must be visible after read from - * queue->write - */ - smp_rmb(); - return queue->storage[queue->read & (queue->size - 1)]; } @@ -130,20 +111,7 @@ VCHIQ_HEADER_T *vchiu_queue_pop(VCHIU_QUEUE_T *queue) flush_signals(current); } - /* - * Read from queue->storage must be visible after read from - * queue->write - */ - smp_rmb(); - header = queue->storage[queue->read & (queue->size - 1)]; - - /* - * Read from queue->storage must be visible before write to - * queue->read - */ - smp_mb(); - queue->read++; complete(&queue->pop);