From mboxrd@z Thu Jan 1 00:00:00 1970 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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 1CA62C47088 for ; Wed, 26 May 2021 18:12:32 +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 AD95E613D8 for ; Wed, 26 May 2021 18:12:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AD95E613D8 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]:52588 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lly18-0000iO-Ib for qemu-devel@archiver.kernel.org; Wed, 26 May 2021 14:12:30 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:52386) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1llxbs-0003Zy-4B for qemu-devel@nongnu.org; Wed, 26 May 2021 13:46:25 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:54302) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1llxbm-0008Tu-93 for qemu-devel@nongnu.org; Wed, 26 May 2021 13:46:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1622051177; 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=8/ZCBza/TJxM/WPXTdZDWfK95h1Zn3I9JZbEie5sy1c=; b=VT6pJVlGWwf+nx3ay9d5ZDdCuLGJ8cGZ2m9lE6KGSHcX2VMXkKA/oTOvhaFBt2nGCRF7+E hxmKA+iVmdN+YaCEIHQqH9BnfxHmrTyCvfsB226NcGrwSvGmfSzWIK9V7G+F5Q2eT6Jz52 GDn9/0/76b4wo9DfYlrEIIfeJIAsG9o= 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-10-HA2vlz3zMgOvMwnce_I1bw-1; Wed, 26 May 2021 13:46:15 -0400 X-MC-Unique: HA2vlz3zMgOvMwnce_I1bw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6C80A1005D55; Wed, 26 May 2021 17:46:14 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-114-247.ams2.redhat.com [10.36.114.247]) by smtp.corp.redhat.com (Postfix) with ESMTP id 834885D9C6; Wed, 26 May 2021 17:46:06 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, kwolf@redhat.com, vgoyal@redhat.com, ma.mandourr@gmail.com, lizhijian@cn.fujitsu.com Subject: [PULL 06/15] virtiofsd: Simplify skip byte logic Date: Wed, 26 May 2021 18:45:31 +0100 Message-Id: <20210526174540.290588-7-dgilbert@redhat.com> In-Reply-To: <20210526174540.290588-1-dgilbert@redhat.com> References: <20210526174540.290588-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=170.10.133.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.371, 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: peterx@redhat.com, stefanha@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Vivek Goyal 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. Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Connor Kuehl Signed-off-by: Vivek Goyal Message-Id: <20210518213538.693422-6-vgoyal@redhat.com> Signed-off-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 ed5146d7a6..49c7dd788a 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; -- 2.31.1