From patchwork Mon Aug 31 15:01:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 275119 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2FBFC433E2 for ; Mon, 31 Aug 2020 15:06:16 +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 64BF5207EA for ; Mon, 31 Aug 2020 15:06:16 +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="O/jWW8W/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 64BF5207EA 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+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44734 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kClNv-0003l2-H4 for qemu-devel@archiver.kernel.org; Mon, 31 Aug 2020 11:06:15 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44176) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kClJX-0006BD-NY for qemu-devel@nongnu.org; Mon, 31 Aug 2020 11:01:45 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:46879) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kClJW-0004VD-2N for qemu-devel@nongnu.org; Mon, 31 Aug 2020 11:01:43 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1598886101; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Z2PpamRG0wqHHnFH6TPqPqum/uJ9JpSRTxMEU5HEr7w=; b=O/jWW8W/0+lsWBp3f423ajdZeh4hMpzvZDcf3OZzplJuZAzoG2KAIcUMUl0kq6P2U9yN41 MOavhpt+4sSTBSnLd37suORtHWfJdu9ER7B6dIK07ESy7K/qM3HXxXe+eV+myt9k4Howek 2aKvHXXDvcaz6vj7CKxXw1SwIIVFe6M= 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-310-5We50y58NeWRRyTG-dG5xg-1; Mon, 31 Aug 2020 11:01:37 -0400 X-MC-Unique: 5We50y58NeWRRyTG-dG5xg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 35D28801ADD; Mon, 31 Aug 2020 15:01:36 +0000 (UTC) Received: from localhost.localdomain (unknown [10.35.206.190]) by smtp.corp.redhat.com (Postfix) with ESMTP id E906D19C4F; Mon, 31 Aug 2020 15:01:30 +0000 (UTC) From: Maxim Levitsky To: qemu-devel@nongnu.org Subject: [PATCH v4 1/9] scsi/scsi_bus: switch search direction in scsi_device_find Date: Mon, 31 Aug 2020 18:01:16 +0300 Message-Id: <20200831150124.206267-2-mlevitsk@redhat.com> In-Reply-To: <20200831150124.206267-1-mlevitsk@redhat.com> References: <20200831150124.206267-1-mlevitsk@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mlevitsk@redhat.com X-Mimecast-Spam-Score: 0.001 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=63.128.21.124; envelope-from=mlevitsk@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/31 03:02:42 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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 , Stefan Hajnoczi , Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.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 Reviewed-by: Stefan Hajnoczi --- 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 df65cc2223..f8adfbc2a5 100644 --- a/hw/scsi/scsi-bus.c +++ b/hw/scsi/scsi-bus.c @@ -1572,7 +1572,7 @@ 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); @@ -1580,7 +1580,15 @@ 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;