From patchwork Thu Apr 16 20:36:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 11493741 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E16606CA for ; Thu, 16 Apr 2020 20:38:33 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B4B53206A2 for ; Thu, 16 Apr 2020 20:38:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="S9eJX6KF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B4B53206A2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:39094 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jPBHM-00024H-RT for patchwork-qemu-devel@patchwork.kernel.org; Thu, 16 Apr 2020 16:38:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60490) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jPBFX-00080d-N0 for qemu-devel@nongnu.org; Thu, 16 Apr 2020 16:36:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jPBFW-00042d-PU for qemu-devel@nongnu.org; Thu, 16 Apr 2020 16:36:39 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:37706 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jPBFW-00042N-MH for qemu-devel@nongnu.org; Thu, 16 Apr 2020 16:36:38 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1587069398; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ap+Pt4fSPMW5Snij4O6Cep7cm0g2WkDrl1yiJWCRlzk=; b=S9eJX6KF2jmkb95LUUTgsN9tgIS+Io4dhsHttQEEwrDZ7sJLZ+CLRvTZH3h+Ooq+zIOdB7 YsBCorlP7FVjMrbqz2H+WOwOitAzyzttct89OO8DWqY3Cs+TrzXIAPb+3Y/guk2uHmy0Y7 4KNei1cG1SB5fDnwH1oym+jxfrCUss8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-51-77ki8K5WNXmGOUm74Y_f4A-1; Thu, 16 Apr 2020 16:36:34 -0400 X-MC-Unique: 77ki8K5WNXmGOUm74Y_f4A-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CC57018C43C0; Thu, 16 Apr 2020 20:36:33 +0000 (UTC) Received: from maximlenovopc.usersys.redhat.com (unknown [10.35.206.56]) by smtp.corp.redhat.com (Postfix) with ESMTP id C165CA099C; Thu, 16 Apr 2020 20:36:31 +0000 (UTC) From: Maxim Levitsky To: qemu-devel@nongnu.org Subject: [PATCH 1/4] scsi/scsi_bus: switch search direction in scsi_device_find Date: Thu, 16 Apr 2020 23:36:21 +0300 Message-Id: <20200416203624.32366-2-mlevitsk@redhat.com> In-Reply-To: <20200416203624.32366-1-mlevitsk@redhat.com> References: <20200416203624.32366-1-mlevitsk@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Fam Zheng , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost , "Michael S. Tsirkin" , Maxim Levitsky , Paolo Bonzini Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" This change will allow us to convert the bus children list to RCU, while not changing the logic of this function Signed-off-by: Maxim Levitsky --- hw/scsi/scsi-bus.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c index 1c980cab38..7bbc37acec 100644 --- a/hw/scsi/scsi-bus.c +++ b/hw/scsi/scsi-bus.c @@ -1584,7 +1584,7 @@ SCSIDevice *scsi_device_find(SCSIBus *bus, int channel, int id, int lun) BusChild *kid; SCSIDevice *target_dev = NULL; - QTAILQ_FOREACH_REVERSE(kid, &bus->qbus.children, sibling) { + QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) { DeviceState *qdev = kid->child; SCSIDevice *dev = SCSI_DEVICE(qdev); @@ -1592,7 +1592,15 @@ SCSIDevice *scsi_device_find(SCSIBus *bus, int channel, int id, int lun) if (dev->lun == lun) { return dev; } - target_dev = dev; + + /* + * If we don't find exact match (channel/bus/lun), + * we will return the first device which matches channel/bus + */ + + if (!target_dev) { + target_dev = dev; + } } } return target_dev;