From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5E242C433EF for ; Fri, 10 Jun 2022 16:34:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349789AbiFJQei (ORCPT ); Fri, 10 Jun 2022 12:34:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349742AbiFJQd6 (ORCPT ); Fri, 10 Jun 2022 12:33:58 -0400 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 2B69A590BE; Fri, 10 Jun 2022 09:33:50 -0700 (PDT) Received: from linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net (linux.microsoft.com [13.77.154.182]) by linux.microsoft.com (Postfix) with ESMTPSA id C1D2820BE632; Fri, 10 Jun 2022 09:33:49 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com C1D2820BE632 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1654878829; bh=/b3rhCsLk+dR82/EPLL1D6TioCvSqpU+hE4SbKy13BQ=; h=From:To:Subject:Date:From; b=esKR0fKGIjBKjCu22T0Ap88L1UL6DlJf8mLhdNXsQPKzuaxFB9YVh7a2uwUtR/Bj7 gQypSQBNqC601gqM1jlGlI2pe67YLyXVF6yaJNKZCjF6bRc99lpDOd3K0tHGhzmw8R UpYuWjEY0C0pRcnBMPEYJlzTMMf6hemFYyB0+ot0= From: Saurabh Sengar To: kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, ssengar@microsoft.com, mikelley@microsoft.com Subject: [PATCH] scsi: storvsc: Correct sysfs parameters as per Hyper-V storvsc requirement Date: Fri, 10 Jun 2022 09:33:44 -0700 Message-Id: <1654878824-25691-1-git-send-email-ssengar@linux.microsoft.com> X-Mailer: git-send-email 1.8.3.1 Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org This patch corrects 3 parameters: 1. Correct the sysfs entry for maximum hardware transfer limit of single transfer (max_hw_sectors_kb) by setting max_sectors, this was set to default value 512kb before. 2. Correct SGL memory offset alignment as per Hyper-V page size. 3. Correct sg_tablesize which accounts for max SGL segments entries in a single SGL. Signed-off-by: Saurabh Sengar --- drivers/scsi/storvsc_drv.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-) diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index ca3530982e52..3e032660ae36 100644 --- a/drivers/scsi/storvsc_drv.c +++ b/drivers/scsi/storvsc_drv.c @@ -1844,7 +1844,7 @@ static struct scsi_host_template scsi_driver = { .cmd_per_lun = 2048, .this_id = -1, /* Ensure there are no gaps in presented sgls */ - .virt_boundary_mask = PAGE_SIZE-1, + .virt_boundary_mask = HV_HYP_PAGE_SIZE - 1, .no_write_same = 1, .track_queue_depth = 1, .change_queue_depth = storvsc_change_queue_depth, @@ -1969,11 +1969,31 @@ static int storvsc_probe(struct hv_device *device, /* max cmd length */ host->max_cmd_len = STORVSC_MAX_CMD_LEN; + /* max_hw_sectors_kb */ + host->max_sectors = (stor_device->max_transfer_bytes) >> 9; /* - * set the table size based on the info we got - * from the host. + * There are 2 requirements for Hyper-V storvsc sgl segments, + * based on which the below calculation for max segments is + * done: + * + * 1. Except for the first and last sgl segment, all sgl segments + * should be align to HV_HYP_PAGE_SIZE, that also means the + * maximum number of segments in a sgl can be calculated by + * dividing the total max transfer length by HV_HYP_PAGE_SIZE. + * + * 2. Except for the first and last, each entry in the SGL must + * have an offset that is a multiple of HV_HYP_PAGE_SIZE, + * whereas the complete length of transfer may not be aligned + * to HV_HYP_PAGE_SIZE always. This can result in 2 cases: + * Example for unaligned case: Let's say the total transfer + * length is 6 KB, the max segments will be 3 (1,4,1). + * Example for aligned case: Let's say the total transfer length + * is 8KB, then max segments will still be 3(2,4,2) and not 4. + * 4 (read next higher value) segments will only be required + * once the length is at least 2 bytes more then 8KB (read any + * HV_HYP_PAGE_SIZE aligned length). */ - host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT); + host->sg_tablesize = ((stor_device->max_transfer_bytes - 2) >> HV_HYP_PAGE_SHIFT) + 2; /* * For non-IDE disks, the host supports multiple channels. * Set the number of HW queues we are supporting. -- 2.25.1