From patchwork Fri Sep 4 02:09:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tom Yan X-Patchwork-Id: 274562 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=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 CC67DC43461 for ; Fri, 4 Sep 2020 02:10:56 +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 8497F2067C for ; Fri, 4 Sep 2020 02:10:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="sxTL1221" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8497F2067C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:57742 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kE1Bn-0006p5-Mg for qemu-devel@archiver.kernel.org; Thu, 03 Sep 2020 22:10:55 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37884) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kE1AI-0005Qf-1p; Thu, 03 Sep 2020 22:09:22 -0400 Received: from mail-pj1-x1042.google.com ([2607:f8b0:4864:20::1042]:34226) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kE1AG-0002cp-KG; Thu, 03 Sep 2020 22:09:21 -0400 Received: by mail-pj1-x1042.google.com with SMTP id n3so4513248pjq.1; Thu, 03 Sep 2020 19:09:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=wwJlpHbGqD6yuQffmEe6pHXUpY2gNY6RxukEHADyMls=; b=sxTL1221iQ0izLkA4qRYFJwMdEgyruNyoxF/WWqwN36w3TxBK4g9GZCb7HoUuZW0H/ g/p/9m71w5SUvKImfOQfmmAFREWyeuQlP0d3TTfm07SLdNOfbGyB8pxElRDAwTuTpD/S IUGhX6F4FqBsVJD+E9+QxNYso2TPCNhXO+9t3NIHlItOQkfZ1hCUdr48SDUoVmf5Z4uL kaHcNkYVHPyPxS7xoy3TuXXl6c1wso3DiXocxRsY/VvKWLf93IdIt72TCq6Jm+MAybOd 5aRX2HMGmmGZmlwwRpslGTrVyq4B/NwFfIotIYgnM0E0GVAxinvVHjpAqz1NEN/arlQu sVxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=wwJlpHbGqD6yuQffmEe6pHXUpY2gNY6RxukEHADyMls=; b=PCnar7+Dz3GLlx8s8HYBPVN4LcR93uC+xuVFz8AISItvYn18WsyK3SEWO5RWB+H85n ekDgoPv9U3TwKnNp3+tXzLOJo8QFMacaaqehdevncWTiddZYPU+B0siw/IEs32tYdwWx K5svRih2vcxvNaBWGJvDxGunR2BfGyvXYxYoCoqcVjbFvNfnIrgmjuLbR+A3iH4BLlNQ XNVqbSrOJ+c3g9Gf3b/SpPt+Qoe92FEAIOrItMQ0rAejApzi/97wETVY73+UlKfClUDA ME2wffKfXPXZOEc5ZiAb9FYmh4WpWU1AbEVnLgekZpRgS+1D+HDhTv0TUe57wa1rMaj5 LqMg== X-Gm-Message-State: AOAM531M5nNV5nqhDNtFdFHeAT8PVDCiutqvv3foJCOdTB7al/bmZa6K Nxvc1c8L3s6aFxq+BbebPoqbHxD8GwU= X-Google-Smtp-Source: ABdhPJwu4B+FOu3m8jKtnikiZn4GvH3fE0Tj3jgN7ulW5sVUhPsYdGhptK9LfuTbtiOxDA6j5LijTQ== X-Received: by 2002:a17:90b:1256:: with SMTP id gx22mr6083420pjb.47.1599185358494; Thu, 03 Sep 2020 19:09:18 -0700 (PDT) Received: from localhost.localdomain ([161.81.62.213]) by smtp.gmail.com with ESMTPSA id n11sm4047178pgd.2.2020.09.03.19.09.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Sep 2020 19:09:17 -0700 (PDT) From: Tom Yan To: qemu-block@nongnu.org, kwolf@redhat.com, mreitz@redhat.com, qemu-devel@nongnu.org Subject: [PATCH v4 2/2] file-posix: add sg_get_max_segments that actually works with sg Date: Fri, 4 Sep 2020 10:09:07 +0800 Message-Id: <20200904020907.241550-2-tom.ty89@gmail.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200904020907.241550-1-tom.ty89@gmail.com> References: <20200904020907.241550-1-tom.ty89@gmail.com> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::1042; envelope-from=tom.ty89@gmail.com; helo=mail-pj1-x1042.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: -17 X-Spam_score: -1.8 X-Spam_bar: - X-Spam_report: (-1.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_ENVFROM_END_DIGIT=0.25, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, 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: Tom Yan Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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 --- block/file-posix.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/block/file-posix.c b/block/file-posix.c index 411a23cf99..9e37594145 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -1178,6 +1178,21 @@ static int sg_get_max_transfer_length(int fd) #endif } +static int sg_get_max_segments(int fd) +{ +#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) @@ -1268,7 +1283,7 @@ 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);