From patchwork Tue May 11 21:37:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vivek Goyal X-Patchwork-Id: 1477316 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=IXgI/f08; dkim-atps=neutral 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 ozlabs.org (Postfix) with ESMTPS id 4Ffrry22fHz9sWp for ; Wed, 12 May 2021 07:38:40 +1000 (AEST) Received: from localhost ([::1]:46134 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lga5O-0007OP-Pa for incoming@patchwork.ozlabs.org; Tue, 11 May 2021 17:38:38 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51058) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lga4f-0007MR-Od for qemu-devel@nongnu.org; Tue, 11 May 2021 17:37:53 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:29509) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lga4d-0005tO-B7 for qemu-devel@nongnu.org; Tue, 11 May 2021 17:37:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1620769070; 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=CijRO4JS5NXE0airXkt/GzHEVDw5bRvQGeBh4XaQ974=; b=IXgI/f083wReZGDd4knT46f/1j835PKASciOV74viKNqkqjFf3twc/bYNiJzpAGhO4rtgM NWk1oYd/xWi2d2I19pJHRA5oZps+4ztQ9XE/Xp5g0tZXwqiaE/Tj8TCyy3flMGqUmNVe3O aDxtSGHXYK/yfm/NfH9Cwep6BulAqsI= 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-566-70EycKckPISiDnHSG90tmA-1; Tue, 11 May 2021 17:37:48 -0400 X-MC-Unique: 70EycKckPISiDnHSG90tmA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B21F0106BAAA for ; Tue, 11 May 2021 21:37:47 +0000 (UTC) Received: from horse.redhat.com (ovpn-115-221.rdu2.redhat.com [10.10.115.221]) by smtp.corp.redhat.com (Postfix) with ESMTP id 96D2D60938; Tue, 11 May 2021 21:37:47 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id 514CA225FD1; Tue, 11 May 2021 17:37:43 -0400 (EDT) From: Vivek Goyal To: qemu-devel@nongnu.org, virtio-fs@redhat.com Subject: [PATCH 5/7] virtiofsd: Simplify skip byte logic Date: Tue, 11 May 2021 17:37:34 -0400 Message-Id: <20210511213736.281016-6-vgoyal@redhat.com> In-Reply-To: <20210511213736.281016-1-vgoyal@redhat.com> References: <20210511213736.281016-1-vgoyal@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=vgoyal@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.133.124; envelope-from=vgoyal@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.699, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=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: dgilbert@redhat.com, vgoyal@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" We need to skip bytes in two cases. a. Before we start reading into in_sg, we need to skip iov_len bytes in the beginning which typically will have fuse_out_header. b. If preadv() does a short read, then we need to retry preadv() with remainig bytes and skip the bytes preadv() read in short read. For case a, there is no reason that skipping logic be inside the while loop. Move it outside. And only retain logic "b" inside while loop. Also get rid of variable "skip_size". Looks like we can do without it. Signed-off-by: Vivek Goyal Reviewed-by: Dr. David Alan Gilbert --- tools/virtiofsd/fuse_virtio.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c index ccad2b3f8a..434fe401cf 100644 --- a/tools/virtiofsd/fuse_virtio.c +++ b/tools/virtiofsd/fuse_virtio.c @@ -392,17 +392,11 @@ int virtio_send_data_iov(struct fuse_session *se, struct fuse_chan *ch, unsigned int in_sg_cpy_count = in_num; /* skip over parts of in_sg that contained the header iov */ - size_t skip_size = iov_len; + iov_discard_front(&in_sg_ptr, &in_sg_cpy_count, iov_len); do { - if (skip_size != 0) { - iov_discard_front(&in_sg_ptr, &in_sg_cpy_count, skip_size); - } - - fuse_log(FUSE_LOG_DEBUG, - "%s: after skip skip_size=%zd in_sg_cpy_count=%d " - "len remaining=%zd\n", __func__, skip_size, in_sg_cpy_count, - len); + fuse_log(FUSE_LOG_DEBUG, "%s: in_sg_cpy_count=%d len remaining=%zd\n", + __func__, in_sg_cpy_count, len); ret = preadv(buf->buf[0].fd, in_sg_ptr, in_sg_cpy_count, buf->buf[0].pos); @@ -421,7 +415,7 @@ int virtio_send_data_iov(struct fuse_session *se, struct fuse_chan *ch, if (ret < len && ret) { fuse_log(FUSE_LOG_DEBUG, "%s: ret < len\n", __func__); /* Skip over this much next time around */ - skip_size = ret; + iov_discard_front(&in_sg_ptr, &in_sg_cpy_count, ret); buf->buf[0].pos += ret; len -= ret;