From patchwork Fri Sep 4 01:33:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tom Yan X-Patchwork-Id: 274564 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 79C9EC43461 for ; Fri, 4 Sep 2020 01:34:50 +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 3BC6820716 for ; Fri, 4 Sep 2020 01:34:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="kej30fI+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3BC6820716 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]:43630 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kE0cr-00054t-F7 for qemu-devel@archiver.kernel.org; Thu, 03 Sep 2020 21:34:49 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57690) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kE0bQ-0003m6-Ta; Thu, 03 Sep 2020 21:33:20 -0400 Received: from mail-pj1-x1043.google.com ([2607:f8b0:4864:20::1043]:34037) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kE0bP-00063O-CU; Thu, 03 Sep 2020 21:33:20 -0400 Received: by mail-pj1-x1043.google.com with SMTP id n3so4477254pjq.1; Thu, 03 Sep 2020 18:33:18 -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=kej30fI+TFjB/ZAxcFVAjiZ2pVbW2AkwM2esVyhKxt/wEPeAxpMfcLBS3lss2he04i 89mu4m5OaOWX1OkHU3Rju0yZGegaNPvNZSmLe2sklMDYTPU/uWQLSVU3xvAdGNMz+/2w hZ9oRFP2xC+RYUoMkY8Fs7KGN3Ikto9YL+Qe5kJnZ8DcuIguLMirac6h4KvhaRyWyWtK XdzEGnY4SEnR6Zpfy3o0GKIV8WYlre1RYL69E2SPdeRZJ6fJyQ0jAp05yOwhtt1oKCeD Z1oafhlYmVwNeR60VLSCl7qZEXlZdmIGkQWYeZuZMp87AZ2a9bjb8op/eRNzyjnk4Tu8 +CeA== 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=T07fH/pRk8HtBLyrFlqmANlM9QkOEw8Fzs9pRGkzl19OSqTFkoDngr/3uYD6n4hmDu zPLhB0cXSLcLwEKOQMtiAMYN5Ws+OyED9YiRcfaHFa8F+XwQ13mPjsKUe4RPUp/jTb+t OuP9xCNRtWeKhtroNdaOjTinHh6q0j5CJpshacjbwu/JLBOOG7Y6veNUcjwi38J720hc zCyUTULvP7GoCzdDPyDIHcAAwC9dfrOjR7/oo6Wo3iWsROiru8EV6FsDIvX3Y9BlB/k1 62mp+dWYDsW13zqq0hLHH097f8RNstRGFgi9VBVskf0axYtwcJnXE5hsfeO/HU8GdDKr 4hIg== X-Gm-Message-State: AOAM5303RkmQk8cEpc0CZZX+SIPr3Srjhw1oD2ScqGBQCPn9tSFeyymG vcIdWe/46g73/4JCdKIZnYg1WbMUpy8= X-Google-Smtp-Source: ABdhPJxJXCXXuYXkl7nY88SAMwHzen6bD9OkvfoYcMgfN4pOQ+FIf2xkCRnRZJIFj5RXBvxEGhw53w== X-Received: by 2002:a17:90a:4382:: with SMTP id r2mr5636473pjg.144.1599183197261; Thu, 03 Sep 2020 18:33:17 -0700 (PDT) Received: from localhost.localdomain ([161.81.62.213]) by smtp.gmail.com with ESMTPSA id gj16sm3643158pjb.13.2020.09.03.18.33.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Sep 2020 18:33:16 -0700 (PDT) From: Tom Yan To: qemu-block@nongnu.org, kwolf@redhat.com, mreitz@redhat.com, qemu-devel@nongnu.org Subject: [PATCH RESEND v2 2/2] file-posix: add sg_get_max_segments that actually works with sg Date: Fri, 4 Sep 2020 09:33:04 +0800 Message-Id: <20200904013304.220336-2-tom.ty89@gmail.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200904013304.220336-1-tom.ty89@gmail.com> References: <20200904013304.220336-1-tom.ty89@gmail.com> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::1043; envelope-from=tom.ty89@gmail.com; helo=mail-pj1-x1043.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);