From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754176AbdKFSBj (ORCPT ); Mon, 6 Nov 2017 13:01:39 -0500 Received: from mx1.redhat.com ([209.132.183.28]:33236 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753552AbdKFSBh (ORCPT ); Mon, 6 Nov 2017 13:01:37 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 76C17B5CF Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=cavery@redhat.com Subject: Re: [PATCH] storvsc: Avoid excessive host scan on controller change To: Long Li , "K . Y . Srinivasan" , Haiyang Zhang , Stephen Hemminger , "James E . J . Bottomley" , "Martin K . Petersen" , devel@linuxdriverproject.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org References: <20171031215808.11629-1-longli@exchange.microsoft.com> From: Cathy Avery Message-ID: <5A00A37F.9070601@redhat.com> Date: Mon, 6 Nov 2017 13:01:35 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.0 MIME-Version: 1.0 In-Reply-To: <20171031215808.11629-1-longli@exchange.microsoft.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Mon, 06 Nov 2017 18:01:37 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/31/2017 05:58 PM, Long Li wrote: > From: Long Li > > When there are multiple disks attached to the same SCSI controller, > the host may send several VSTOR_OPERATION_REMOVE_DEVICE or > VSTOR_OPERATION_ENUMERATE_BUS messages in a row, to indicate there is a > change on the SCSI controller. In response, storvsc rescans the SCSI host. > > There is no need to do multiple scans on the same host. Fix the code to do > only one scan. > > Signed-off-by: Long Li > --- > drivers/scsi/storvsc_drv.c | 26 +++++++++++--------------- > 1 file changed, 11 insertions(+), 15 deletions(-) > > diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c > index 6febcdb..b602f52 100644 > --- a/drivers/scsi/storvsc_drv.c > +++ b/drivers/scsi/storvsc_drv.c > @@ -488,6 +488,8 @@ struct hv_host_device { > unsigned char target; > struct workqueue_struct *handle_error_wq; > char work_q_name[20]; > + struct work_struct host_scan_work; > + struct Scsi_Host *host; > }; > > struct storvsc_scan_work { > @@ -516,13 +518,12 @@ static void storvsc_device_scan(struct work_struct *work) > > static void storvsc_host_scan(struct work_struct *work) > { > - struct storvsc_scan_work *wrk; > struct Scsi_Host *host; > struct scsi_device *sdev; > + struct hv_host_device *host_device = > + container_of(work, struct hv_host_device, host_scan_work); > > - wrk = container_of(work, struct storvsc_scan_work, work); > - host = wrk->host; > - > + host = host_device->host; > /* > * Before scanning the host, first check to see if any of the > * currrently known devices have been hot removed. We issue a > @@ -542,8 +543,6 @@ static void storvsc_host_scan(struct work_struct *work) > * Now scan the host to discover LUNs that may have been added. > */ > scsi_scan_host(host); > - > - kfree(wrk); > } > > static void storvsc_remove_lun(struct work_struct *work) > @@ -1119,8 +1118,7 @@ static void storvsc_on_receive(struct storvsc_device *stor_device, > struct vstor_packet *vstor_packet, > struct storvsc_cmd_request *request) > { > - struct storvsc_scan_work *work; > - > + struct hv_host_device *host_dev; > switch (vstor_packet->operation) { > case VSTOR_OPERATION_COMPLETE_IO: > storvsc_on_io_completion(stor_device, vstor_packet, request); > @@ -1128,13 +1126,9 @@ static void storvsc_on_receive(struct storvsc_device *stor_device, > > case VSTOR_OPERATION_REMOVE_DEVICE: > case VSTOR_OPERATION_ENUMERATE_BUS: > - work = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC); > - if (!work) > - return; > - > - INIT_WORK(&work->work, storvsc_host_scan); > - work->host = stor_device->host; > - schedule_work(&work->work); > + host_dev = shost_priv(stor_device->host); > + queue_work( > + host_dev->handle_error_wq, &host_dev->host_scan_work); > break; > > case VSTOR_OPERATION_FCHBA_DATA: > @@ -1747,6 +1741,7 @@ static int storvsc_probe(struct hv_device *device, > > host_dev->port = host->host_no; > host_dev->dev = device; > + host_dev->host = host; > > > stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL); > @@ -1815,6 +1810,7 @@ static int storvsc_probe(struct hv_device *device, > create_singlethread_workqueue(host_dev->work_q_name); > if (!host_dev->handle_error_wq) > goto err_out2; > + INIT_WORK(&host_dev->host_scan_work, storvsc_host_scan); > /* Register the HBA and start the scsi bus scan */ > ret = scsi_add_host(host, &device->device); > if (ret != 0) I've tested this patch with both a multipath failover while running fio and taking hyperV snap shots while luns are being hot added and removed. Tested-by: Cathy Avery