From patchwork Wed Nov 4 17:32:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 318589 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 8A634C55179 for ; Wed, 4 Nov 2020 17:36:22 +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 E7C072067D for ; Wed, 4 Nov 2020 17:36:21 +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="dxZiQMNz" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E7C072067D 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]:52874 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kaMho-00076g-5w for qemu-devel@archiver.kernel.org; Wed, 04 Nov 2020 12:36:20 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:34442) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kaMeH-0002oz-Mx for qemu-devel@nongnu.org; Wed, 04 Nov 2020 12:32:41 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:43340) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kaMeF-0000eE-8j for qemu-devel@nongnu.org; Wed, 04 Nov 2020 12:32:41 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1604511158; 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=HwFjO0iC2QO9Q3sXzEwRi6E1KuOJkKul953Lgsb1neM=; b=dxZiQMNzIbFkpcgBv1x2syXhirjiE/E+djdNSO21QlfDstmg7TF5wec9fEONGvWiwWvpS0 RzUA2A2cUs3sOxZIi/WPqE4KjxpkVvefmwhMAfNfMCkCkZSFpL0u7keGpEvZquCUDfzEP4 tlZiHD9IobyhJY3IxU23s32LaveE4Kk= 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-278-vIvnZyeOMR2XIoRcmO0IMw-1; Wed, 04 Nov 2020 12:32:35 -0500 X-MC-Unique: vIvnZyeOMR2XIoRcmO0IMw-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 C71D01084D70; Wed, 4 Nov 2020 17:32:33 +0000 (UTC) Received: from localhost.localdomain (unknown [10.35.207.23]) by smtp.corp.redhat.com (Postfix) with ESMTP id E495675128; Wed, 4 Nov 2020 17:32:30 +0000 (UTC) From: Maxim Levitsky To: qemu-devel@nongnu.org Subject: [PATCH 2/5] file-posix: add sg_get_max_segments that actually works with sg Date: Wed, 4 Nov 2020 19:32:14 +0200 Message-Id: <20201104173217.417538-3-mlevitsk@redhat.com> In-Reply-To: <20201104173217.417538-1-mlevitsk@redhat.com> References: <20201104173217.417538-1-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 = 2020/11/03 22:09:52 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 , Kevin Wolf , Stefan Hajnoczi , qemu-block@nongnu.org, Peter Lieven , Tom Yan , Ronnie Sahlberg , Paolo Bonzini , Maxim Levitsky , Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Tom Yan sg devices have different major/minor than their corresponding block devices. Using sysfs to get max segments never really worked for them. Fortunately the sg driver provides an ioctl to get sg_tablesize, which is apparently equivalent to max segments. Signed-off-by: Tom Yan Signed-off-by: Maxim Levitsky --- block/file-posix.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/block/file-posix.c b/block/file-posix.c index 6581f41b2b..c4df757504 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -1181,6 +1181,26 @@ static int sg_get_max_transfer_length(int fd) #endif } +static int sg_get_max_segments(int fd) +{ + /* + * /dev/sg* character devices report 'max_segments' via + * SG_GET_SG_TABLESIZE ioctl + */ + +#ifdef SG_GET_SG_TABLESIZE + long max_segments = 0; + + if (ioctl(fd, SG_GET_SG_TABLESIZE, &max_segments) == 0) { + return max_segments; + } else { + return -errno; + } +#else + return -ENOSYS; +#endif +} + static int get_max_transfer_length(int fd) { #if defined(BLKSECTGET) && defined(BLKSSZGET) @@ -1269,7 +1289,7 @@ static void hdev_refresh_limits(BlockDriverState *bs, Error **errp) bs->bl.max_transfer = pow2floor(ret); } - ret = get_max_segments(s->fd); + ret = bs->sg ? sg_get_max_segments(s->fd) : get_max_segments(s->fd); if (ret > 0) { bs->bl.max_transfer = MIN_NON_ZERO(bs->bl.max_transfer, ret * qemu_real_host_page_size);