From patchwork Fri Sep 4 00:51:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tom Yan X-Patchwork-Id: 306231 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 11573C433E2 for ; Fri, 4 Sep 2020 00:52:13 +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 C2A3920716 for ; Fri, 4 Sep 2020 00:52:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="GIhDo6TB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C2A3920716 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]:47242 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kDzxb-00084z-Vi for qemu-devel@archiver.kernel.org; Thu, 03 Sep 2020 20:52:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:52260) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kDzwx-0007DP-Mf for qemu-devel@nongnu.org; Thu, 03 Sep 2020 20:51:31 -0400 Received: from mail-pg1-x543.google.com ([2607:f8b0:4864:20::543]:40065) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kDzww-0001VK-41 for qemu-devel@nongnu.org; Thu, 03 Sep 2020 20:51:31 -0400 Received: by mail-pg1-x543.google.com with SMTP id h12so3438734pgm.7 for ; Thu, 03 Sep 2020 17:51:29 -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=haFiIuZcpa2HR7b3wPU26vJsTkZCNX1fBT9PCrfxrgI=; b=GIhDo6TBVE2vxM0EEF5gA5TnYYd/xjef9BN0fw+iBsgiP21UZ7FKiifXh7eyLNKT/N ZIOIKIK/LQhVOHRR5F/us6nLCWmSt7Fvv9btQ/ua1w023hXKyRG658iZhgZgVaOg9ztA CZUHVTgyczgRjRfQ04lZPbrzghFIOFK5TtLEjca54nRXopBg5iAu07CZDeYJH5u3tn3w jWrE4GiKGH8MELX4x2D0zrZGTJBs+ar8JOzvg777A882N8CEKXx492sIiDM/N05jLrjl yqAESk+zEJCYRj7/vXhzDA+l8Qb2zQR1ALBL+9PpZPpDFdRZpY/tgRKO/vpyrshMKAyl ix4g== 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=haFiIuZcpa2HR7b3wPU26vJsTkZCNX1fBT9PCrfxrgI=; b=cPyF9Rq4wZF+zPmGel/MFCgOSp52f8VvC4UXB+Bje9YZo6fuzeAlsv+RTU74PcMd0Q oFKKqvoR7HZD6Ziunkr923N0u3G3RHyM39C03QGOo09984KMc41xjffhXkPUGBAnpMTo /kPZmAGXJmxpo2z8VQAJQQKvpz6GL6IEGncsiCqctpQLFHUrgnbaPkIZTaEtVzrvrTSc WMOJvqWV9KtMY9EX04yxemle84pI3r3leMP9oiGhGbY0UG1nxsqDeOrgQXjX92gM3kdN URCPjvw9ptmY474QgM46ekZsT0Qq6EMdH6zNfrc7/nwqLW/bzx1JJgJtNzhIBzAXFZ4a LayA== X-Gm-Message-State: AOAM530Bd4dAvbIg5rC0oTZQrOyMyjxeJPuNTlg8o4tUFg4qnTQb4T9s mG5uDr24mVSmQjCXLpARofqebz0uLD0= X-Google-Smtp-Source: ABdhPJytus4rZifRSdNduHuFag0ThASWhmbPg5iU81SMQjKgVX+Td716CWtMulit7xvlTpcv/Sq6BA== X-Received: by 2002:aa7:8645:0:b029:13c:de96:6fde with SMTP id a5-20020aa786450000b029013cde966fdemr3492120pfo.14.1599180688260; Thu, 03 Sep 2020 17:51:28 -0700 (PDT) Received: from localhost.localdomain ([161.81.62.213]) by smtp.gmail.com with ESMTPSA id u22sm3685652pgi.85.2020.09.03.17.51.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Sep 2020 17:51:27 -0700 (PDT) From: Tom Yan To: qemu-devel@nongnu.org Subject: [PATCH v2 2/2] file-posix: add sg_get_max_segments that actually works with sg Date: Fri, 4 Sep 2020 08:51:18 +0800 Message-Id: <20200904005118.151296-2-tom.ty89@gmail.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200904005118.151296-1-tom.ty89@gmail.com> References: <20200904005118.151296-1-tom.ty89@gmail.com> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::543; envelope-from=tom.ty89@gmail.com; helo=mail-pg1-x543.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 0c9124c8aa..d2cd9a3362 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) @@ -1267,7 +1282,7 @@ 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);