From patchwork Sat Nov 27 15:19:26 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Wilck X-Patchwork-Id: 12642347 X-Patchwork-Delegate: christophe.varoqui@free.fr Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C4AEDC433FE for ; Sat, 27 Nov 2021 15:21:00 +0000 (UTC) Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-150-yr0hUdrVPXaNNlYxxL_gHg-1; Sat, 27 Nov 2021 10:20:56 -0500 X-MC-Unique: yr0hUdrVPXaNNlYxxL_gHg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C396C10168C0; Sat, 27 Nov 2021 15:20:50 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A99875C3DF; Sat, 27 Nov 2021 15:20:50 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 8552E4A710; Sat, 27 Nov 2021 15:20:50 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 1ARFJv8H000417 for ; Sat, 27 Nov 2021 10:19:57 -0500 Received: by smtp.corp.redhat.com (Postfix) id A26592026D69; Sat, 27 Nov 2021 15:19:57 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast03.extmail.prod.ext.rdu2.redhat.com [10.11.55.19]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9E5EF2026D65 for ; Sat, 27 Nov 2021 15:19:57 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 860A7811E76 for ; Sat, 27 Nov 2021 15:19:57 +0000 (UTC) Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-382-PCt1c1_OOlGQgoyx5hVj8g-1; Sat, 27 Nov 2021 10:19:55 -0500 X-MC-Unique: PCt1c1_OOlGQgoyx5hVj8g-1 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 318AD1FC9E; Sat, 27 Nov 2021 15:19:54 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id D915713AAD; Sat, 27 Nov 2021 15:19:53 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id SCH/MplMomErFgAAMHmgww (envelope-from ); Sat, 27 Nov 2021 15:19:53 +0000 From: mwilck@suse.com To: Christophe Varoqui , Benjamin Marzinski Date: Sat, 27 Nov 2021 16:19:26 +0100 Message-Id: <20211127151929.7727-34-mwilck@suse.com> In-Reply-To: <20211127151929.7727-1-mwilck@suse.com> References: <20211127151929.7727-1-mwilck@suse.com> MIME-Version: 1.0 X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-MIME-Autoconverted: from quoted-printable to 8bit by lists01.pubmisc.prod.ext.phx2.redhat.com id 1ARFJv8H000417 X-loop: dm-devel@redhat.com Cc: lixiaokeng@huawei.com, Chongyun Wu , dm-devel@redhat.com, Martin Wilck Subject: [dm-devel] [PATCH v3 32/35] multipathd: uxlsnr: use poll loop for sending, too X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com From: Martin Wilck send_packet() may busy-loop. By polling for POLLOUT, we can avoid that, even if it's very unlikely in practice. Signed-off-by: Martin Wilck Reviewed-by: Benjamin Marzinski --- multipathd/uxlsnr.c | 41 ++++++++++++++++++++++++++++++----------- 1 file changed, 30 insertions(+), 11 deletions(-) diff --git a/multipathd/uxlsnr.c b/multipathd/uxlsnr.c index 1ebcf10..c5da569 100644 --- a/multipathd/uxlsnr.c +++ b/multipathd/uxlsnr.c @@ -447,7 +447,6 @@ static int client_state_machine(struct client *c, struct vectors *vecs, short revents) { ssize_t n; - const char *buf; condlog(4, "%s: cli[%d] poll=%x state=%d cmd=\"%s\" repl \"%s\"", __func__, c->fd, revents, c->state, c->cmd, get_strbuf_str(&c->reply)); @@ -527,7 +526,8 @@ static int client_state_machine(struct client *c, struct vectors *vecs, free_keys(c->cmdvec); c->cmdvec = NULL; set_client_state(c, CLT_SEND); - return STM_CONT; + /* Wait for POLLOUT */ + return STM_BREAK; } else { condlog(4, "%s: cli[%d] waiting for lock", __func__, c->fd); return STM_BREAK; @@ -538,22 +538,38 @@ static int client_state_machine(struct client *c, struct vectors *vecs, free_keys(c->cmdvec); c->cmdvec = NULL; set_client_state(c, CLT_SEND); - return STM_CONT; + /* Wait for POLLOUT */ + return STM_BREAK; case CLT_SEND: if (get_strbuf_len(&c->reply) == 0) default_reply(c, c->error); - buf = get_strbuf_str(&c->reply); + if (c->cmd_len == 0) { + size_t len = get_strbuf_len(&c->reply) + 1; - if (send_packet(c->fd, buf) != 0) - dead_client(c); - else - condlog(4, "cli[%d]: Reply [%zu bytes]", c->fd, - get_strbuf_len(&c->reply) + 1); - reset_strbuf(&c->reply); + if (send(c->fd, &len, sizeof(len), MSG_NOSIGNAL) + != sizeof(len)) + c->error = -ECONNRESET; + c->cmd_len = len; + return STM_BREAK; + } - set_client_state(c, CLT_RECV); + if (c->len < c->cmd_len) { + const char *buf = get_strbuf_str(&c->reply); + + n = send(c->fd, buf + c->len, c->cmd_len, MSG_NOSIGNAL); + if (n == -1) { + if (!(errno == EAGAIN || errno == EINTR)) + c->error = -ECONNRESET; + } else + c->len += n; + } + + if (c->len >= c->cmd_len) { + condlog(4, "cli[%d]: Reply [%zu bytes]", c->fd, c->cmd_len); + set_client_state(c, CLT_RECV); + } return STM_BREAK; default: @@ -687,6 +703,9 @@ void *uxsock_listen(long ux_sock, void *trigger_data) case CLT_RECV: polls[i].events = POLLIN; break; + case CLT_SEND: + polls[i].events = POLLOUT; + break; default: /* don't poll for this client */ continue;