From patchwork Fri Oct 2 17:35:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 272162 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=-12.6 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,USER_AGENT_GIT 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 7C461C4363D for ; Fri, 2 Oct 2020 17:45:59 +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 1F38C206A5 for ; Fri, 2 Oct 2020 17:45:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="oOdc85EI" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1F38C206A5 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]:50146 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kOP82-0001Nw-7j for qemu-devel@archiver.kernel.org; Fri, 02 Oct 2020 13:45:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45068) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kOOyY-0000Yi-3l for qemu-devel@nongnu.org; Fri, 02 Oct 2020 13:36:10 -0400 Received: from mail-wm1-x32f.google.com ([2a00:1450:4864:20::32f]:35657) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kOOyW-0003KN-04 for qemu-devel@nongnu.org; Fri, 02 Oct 2020 13:36:09 -0400 Received: by mail-wm1-x32f.google.com with SMTP id y15so2574517wmi.0 for ; Fri, 02 Oct 2020 10:36:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ZPbac6yldkPR9wbmEuvA0p1poWNownh7RtPwmzH/4gc=; b=oOdc85EI4W3FKST0yJcry7ZwPq6+GyCFzwdhbEYAbPTD7qBEFSQMh6v1exLLslLdws XXb7sPuZg36mEynvdTSHIIU6TUII2uK6rDAC0sEf712nptOtQpfuz6m9Qe0rEoneZi6n rbUyvRYOJM7iJ0wsy5G9sCRqhRCkPKPZit5K9yuLXgAnDiaXTbULfhA9USP597fIPZ64 McM4+xAmFf6ucANeQwYsWoahxosCLfK1Rz2q+oXgHRk873dCGd5oudMDvLTwlwcdcXQu dG5T97boaTktihbaf3C2Rmg8jWmhzuNeu5yU4c5Z823K7Vf9P+DfBqickqBiUhTsMljn k9tQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; bh=ZPbac6yldkPR9wbmEuvA0p1poWNownh7RtPwmzH/4gc=; b=UnKRb4tcEQ3gfYW84/pyedvZwE/073YYLD8M2zGpbi+qfaqGfehDZ6NJzb1Y7pCsPi tH2d4WZBw2b8mkKuZBP121xk6i1djEKQdIdhgesfDF1H29jLyzh/5Qf1FCcRiX1wz4Oh zIlmkTMrlzCZDEJ/CiCLz5ekmmn12qiYtM26JILVLGF+OK1+phf8VwQz7SAyWsKJIr+i egvEQwIX+9WpH5NEbo/5y7SHh/IRFiLee3cniyJCGbtBKAWMDNrnun5JFTCv8acRjI5m Ty86jBivPkSGjCRAqczQkuzk5/OfLUGd7Ody8nGU7CUXcrZpMGJzBX68JQj8QqUIK78A OWEg== X-Gm-Message-State: AOAM5323NBPhpwWh0DNJ9vmq5qtGC/m5D26uqOjjfh9pFAcyjDcnHooi oCQXPNkOCy7SKIW0zK2gJDHpV2ghbls= X-Google-Smtp-Source: ABdhPJzw6ONK159SmQaIfdjsJfS6cXvrlj2imZg/u7eq/eC/9ut8EDwVnWFwcye/do752nsplh2Wqg== X-Received: by 2002:a1c:9c8c:: with SMTP id f134mr4033591wme.27.1601660166396; Fri, 02 Oct 2020 10:36:06 -0700 (PDT) Received: from donizetti.redhat.com ([2001:b07:6468:f312:47e0:e742:75ba:b84d]) by smtp.gmail.com with ESMTPSA id l8sm2516454wrx.22.2020.10.02.10.36.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Oct 2020 10:36:05 -0700 (PDT) From: Paolo Bonzini To: qemu-devel@nongnu.org Subject: [PATCH v6 07/10] scsi/scsi-bus: scsi_device_find: don't return unrealized devices Date: Fri, 2 Oct 2020 19:35:55 +0200 Message-Id: <20201002173558.232960-8-pbonzini@redhat.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201002173558.232960-1-pbonzini@redhat.com> References: <20201002173558.232960-1-pbonzini@redhat.com> MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::32f; envelope-from=paolo.bonzini@gmail.com; helo=mail-wm1-x32f.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FORGED_FROMDOMAIN=0.001, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.25, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no 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: Stefan Hajnoczi , Maxim Levitsky Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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,