From patchwork Tue Oct 6 12:39:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 303602 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=-9.6 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 30322C4363D for ; Tue, 6 Oct 2020 12:54:01 +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 909C7206F7 for ; Tue, 6 Oct 2020 12:54:00 +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="EJ7cryII" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 909C7206F7 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]:52168 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kPmTf-0008NK-Mu for qemu-devel@archiver.kernel.org; Tue, 06 Oct 2020 08:53:59 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56306) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kPmGS-00026d-AW for qemu-devel@nongnu.org; Tue, 06 Oct 2020 08:40:21 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:37221) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kPmGO-0007zy-9V for qemu-devel@nongnu.org; Tue, 06 Oct 2020 08:40:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1601988015; 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=EuRqn1J7iWSmQV++SBJtIv2nKA/wlFvqIANpH3g4y4M=; b=EJ7cryIIpsVwiCeNX9WmqM9051EaXP9hjJAUjOo7H+IlOkEJn1N9tE8bHpDlPUDBwvD5TI cWs2LO4Q4T0kv8oeL0b8hel4YTyuWPYYrsWm/D6lJjj+VrXAg1A6w2fRUhe7WibVcjV1Lz dnV8I8Qpzw/1ssXEPosRpU2pFigik50= 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-436-_HA_fltfMMCJMIjcVV7fvQ-1; Tue, 06 Oct 2020 08:40:13 -0400 X-MC-Unique: _HA_fltfMMCJMIjcVV7fvQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6429D1084D63; Tue, 6 Oct 2020 12:40:12 +0000 (UTC) Received: from localhost.localdomain (unknown [10.35.206.84]) by smtp.corp.redhat.com (Postfix) with ESMTP id 572C92C31E; Tue, 6 Oct 2020 12:40:05 +0000 (UTC) From: Maxim Levitsky To: qemu-devel@nongnu.org Subject: [PATCH v7 10/13] scsi/scsi-bus: scsi_device_find: don't return unrealized devices Date: Tue, 6 Oct 2020 15:39:01 +0300 Message-Id: <20201006123904.610658-11-mlevitsk@redhat.com> In-Reply-To: <20201006123904.610658-1-mlevitsk@redhat.com> References: <20201006123904.610658-1-mlevitsk@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mlevitsk@redhat.com X-Mimecast-Spam-Score: 0 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 = 2020/10/06 01:55:55 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.733, 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 , Laurent Vivier , Thomas Huth , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost , qemu-block@nongnu.org, "Michael S. Tsirkin" , Jason Wang , Markus Armbruster , =?utf-8?q?Philippe_Mathieu-Dau?= =?utf-8?b?ZMOp?= , Stefan Hajnoczi , Paolo Bonzini , Maxim Levitsky , John Snow , Stefan Berger Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Paolo Bonzini The device core first places a device on the bus and then realizes it. Make scsi_device_find avoid returing such devices to avoid races in drivers that use an iothread (currently virtio-scsi) Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1812399 Suggested-by: Paolo Bonzini Signed-off-by: Maxim Levitsky Reviewed-by: Stefan Hajnoczi Message-Id: <20200913160259.32145-7-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini --- hw/scsi/scsi-bus.c | 83 +++++++++++++++++++++++++++++----------------- 1 file changed, 53 insertions(+), 30 deletions(-) diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c index 4ab9811cd8..7599113efe 100644 --- a/hw/scsi/scsi-bus.c +++ b/hw/scsi/scsi-bus.c @@ -24,6 +24,55 @@ static void scsi_target_free_buf(SCSIRequest *req); static int next_scsi_bus; +static SCSIDevice *do_scsi_device_find(SCSIBus *bus, + int channel, int id, int lun, + bool include_unrealized) +{ + BusChild *kid; + SCSIDevice *retval = NULL; + + QTAILQ_FOREACH_RCU(kid, &bus->qbus.children, sibling) { + DeviceState *qdev = kid->child; + SCSIDevice *dev = SCSI_DEVICE(qdev); + + if (dev->channel == channel && dev->id == id) { + if (dev->lun == lun) { + retval = dev; + break; + } + + /* + * If we don't find exact match (channel/bus/lun), + * we will return the first device which matches channel/bus + */ + + if (!retval) { + retval = dev; + } + } + } + + /* + * This function might run on the IO thread and we might race against + * main thread hot-plugging the device. + * We assume that as soon as .realized is set to true we can let + * the user access the device. + */ + + if (retval && !include_unrealized && + !qatomic_load_acquire(&retval->qdev.realized)) { + retval = NULL; + } + + return retval; +} + +SCSIDevice *scsi_device_find(SCSIBus *bus, int channel, int id, int lun) +{ + RCU_READ_LOCK_GUARD(); + return do_scsi_device_find(bus, channel, id, lun, false); +} + static void scsi_device_realize(SCSIDevice *s, Error **errp) { SCSIDeviceClass *sc = SCSI_DEVICE_GET_CLASS(s); @@ -137,7 +186,10 @@ static bool scsi_bus_is_address_free(SCSIBus *bus, int channel, int target, int lun, SCSIDevice **p_dev) { - SCSIDevice *d = scsi_device_find(bus, channel, target, lun); + SCSIDevice *d; + + RCU_READ_LOCK_GUARD(); + d = do_scsi_device_find(bus, channel, target, lun, true); if (d && d->lun == lun) { if (p_dev) { *p_dev = d; @@ -1570,35 +1622,6 @@ static char *scsibus_get_fw_dev_path(DeviceState *dev) qdev_fw_name(dev), d->id, d->lun); } -SCSIDevice *scsi_device_find(SCSIBus *bus, int channel, int id, int lun) -{ - BusChild *kid; - SCSIDevice *target_dev = NULL; - - RCU_READ_LOCK_GUARD(); - QTAILQ_FOREACH_RCU(kid, &bus->qbus.children, sibling) { - DeviceState *qdev = kid->child; - SCSIDevice *dev = SCSI_DEVICE(qdev); - - if (dev->channel == channel && dev->id == id) { - if (dev->lun == lun) { - return 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; -} - /* SCSI request list. For simplicity, pv points to the whole device */ static int put_scsi_requests(QEMUFile *f, void *pv, size_t size,