{"id":810257,"url":"http://patchwork.ozlabs.org/api/patches/810257/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20170905191114.5959-2-eblake@redhat.com/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":"","list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20170905191114.5959-2-eblake@redhat.com>","list_archive_url":null,"date":"2017-09-05T19:11:12","name":"[1/3] io: Yield rather than wait when already in coroutine","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"fd045d3d9bf99b04b70911b125668107c392763e","submitter":{"id":6591,"url":"http://patchwork.ozlabs.org/api/people/6591/?format=json","name":"Eric Blake","email":"eblake@redhat.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20170905191114.5959-2-eblake@redhat.com/mbox/","series":[{"id":1634,"url":"http://patchwork.ozlabs.org/api/series/1634/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=1634","date":"2017-09-05T19:11:12","name":"nbd: Use common read/write-all qio functions","version":1,"mbox":"http://patchwork.ozlabs.org/series/1634/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/810257/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/810257/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@bilbo.ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=2001:4830:134:3::11; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=)","ext-mx10.extmail.prod.ext.phx2.redhat.com;\n\tdmarc=none (p=none dis=none) header.from=redhat.com","ext-mx10.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=eblake@redhat.com"],"Received":["from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xmxFP67Fmz9s7g\n\tfor ;\n\tWed, 6 Sep 2017 05:13:13 +1000 (AEST)","from localhost ([::1]:60901 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t)\n\tid 1dpJHb-0001Dw-JX\n\tfor incoming@patchwork.ozlabs.org; Tue, 05 Sep 2017 15:13:11 -0400","from eggs.gnu.org ([2001:4830:134:3::10]:33226)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from ) id 1dpJG5-0000UI-BO\n\tfor qemu-devel@nongnu.org; Tue, 05 Sep 2017 15:11:42 -0400","from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from ) id 1dpJG0-0005aD-IU\n\tfor qemu-devel@nongnu.org; Tue, 05 Sep 2017 15:11:37 -0400","from mx1.redhat.com ([209.132.183.28]:36808)\n\tby eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)\n\t(Exim 4.71) (envelope-from )\n\tid 1dpJFn-0005Q7-Th; Tue, 05 Sep 2017 15:11:20 -0400","from smtp.corp.redhat.com\n\t(int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13])\n\t(using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby mx1.redhat.com (Postfix) with ESMTPS id 0FF88753A2;\n\tTue, 5 Sep 2017 19:11:19 +0000 (UTC)","from red.redhat.com (ovpn-120-228.rdu2.redhat.com [10.10.120.228])\n\tby smtp.corp.redhat.com (Postfix) with ESMTP id DA9F57EF97;\n\tTue, 5 Sep 2017 19:11:17 +0000 (UTC)"],"DMARC-Filter":"OpenDMARC Filter v1.3.2 mx1.redhat.com 0FF88753A2","From":"Eric Blake ","To":"qemu-devel@nongnu.org","Date":"Tue, 5 Sep 2017 14:11:12 -0500","Message-Id":"<20170905191114.5959-2-eblake@redhat.com>","In-Reply-To":"<20170905191114.5959-1-eblake@redhat.com>","References":"<20170905191114.5959-1-eblake@redhat.com>","X-Scanned-By":"MIMEDefang 2.79 on 10.5.11.13","X-Greylist":"Sender IP whitelisted, not delayed by milter-greylist-4.5.16\n\t(mx1.redhat.com [10.5.110.39]);\n\tTue, 05 Sep 2017 19:11:19 +0000 (UTC)","X-detected-operating-system":"by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic]\n\t[fuzzy]","X-Received-From":"209.132.183.28","Subject":"[Qemu-devel] [PATCH 1/3] io: Yield rather than wait when already in\n\tcoroutine","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.21","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"pbonzini@redhat.com, qemu-block@nongnu.org","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"\"Qemu-devel\"\n\t"},"content":"The new qio_channel_{read,write}{,v}_all functions are documented\nas yielding until data is available. When used on a blocking\nchannel, this yield is done via qio_channel_wait() which spawns\na new coroutine under the hood (so it is the new entry point that\nyields as needed); but if we are already in a coroutine (at which\npoint QIO_CHANNEL_ERR_BLOCK is only possible if we are a\nnon-blocking channel), we want to yield the current coroutine\ninstead of spawning a new one.\n\nSigned-off-by: Eric Blake \n---\n io/channel.c | 12 ++++++++++--\n 1 file changed, 10 insertions(+), 2 deletions(-)","diff":"diff --git a/io/channel.c b/io/channel.c\nindex 5e8c2f0a91..9e62794cab 100644\n--- a/io/channel.c\n+++ b/io/channel.c\n@@ -105,7 +105,11 @@ int qio_channel_readv_all(QIOChannel *ioc,\n ssize_t len;\n len = qio_channel_readv(ioc, local_iov, nlocal_iov, errp);\n if (len == QIO_CHANNEL_ERR_BLOCK) {\n- qio_channel_wait(ioc, G_IO_IN);\n+ if (qemu_in_coroutine()) {\n+ qio_channel_yield(ioc, G_IO_IN);\n+ } else {\n+ qio_channel_wait(ioc, G_IO_IN);\n+ }\n continue;\n } else if (len < 0) {\n goto cleanup;\n@@ -143,7 +147,11 @@ int qio_channel_writev_all(QIOChannel *ioc,\n ssize_t len;\n len = qio_channel_writev(ioc, local_iov, nlocal_iov, errp);\n if (len == QIO_CHANNEL_ERR_BLOCK) {\n- qio_channel_wait(ioc, G_IO_OUT);\n+ if (qemu_in_coroutine()) {\n+ qio_channel_yield(ioc, G_IO_OUT);\n+ } else {\n+ qio_channel_wait(ioc, G_IO_OUT);\n+ }\n continue;\n }\n if (len < 0) {\n","prefixes":["1/3"]}